Derive

Aversion to History: A PKZIP/Wikipedia Story

Sat, 05 Apr 2025 10:00:00 +0000

A couple of years ago, while sifting through lots of ZIP archives from old Shareware CD-ROMs, I found quite a few that couldn’t be unzipped, either because they were corrupted, encrypted, or used compression methods that were no longer supported by modern ZIP utilities. That took me on a journey of ZIP (and ARC) decompression, and I created some new PCjs decompression tools in the process, including the ability to create disk images directly from ZIP files.

Of course, you can’t go down that rabbit hole without digging into the history of the ZIP file format, or the person who developed it, Phil Katz, or the first program to create ZIP files: PKZIP. There’s a lot of history there, and many other rabbit holes you can go down, but this post is going to focus on one “hole” in particular.

PKZIP Version History

Specifically, I’m talking about the PKZIP Wikipedia Page and the history of its version history.

I remembered visiting that Wikipedia page several years ago and seeing a fairly detailed history of PKZIP and all its versions. But when I visited the page earlier this year, the version history was gone.

At first, I thought perhaps I misremembered where I’d seen that version history, so I searched the web, and one of the top results was “Survey of PKZIP versions for MS-DOS”” from Jason Summer’s Entropymine blog, which, coincidentally, mentioned the same Wikipedia page:

“I wanted to know exactly what versions of the old PKZIP compression software were publicly released for MS-DOS, and some basic characteristics about them, particularly what compression methods they used when compressing files. Sure, Wikipedia has a list, but it wasn’t quite what I wanted, and it omitted at least one version I was pretty sure existed.”

So I wasn’t wrong. In 2019, Wikipedia had a list, and I was pretty sure I’d seen the same list back in 2022. But now it was gone.

It’s not hard to find the old list – once you know it existed – by browsing the page’s history and choosing, for example, this page from January 2018 (that revision caught my eye only because someone had added information about PKZIP versions 1.93a and 2.04c).

The Great Deletion

On December 3, 2022, Wikipedia user Pppery (someone who never before and never again contributed anything substantive to the page) decided to delete the entire “Version history” section, using the citation WP:NOTCHANGELOG.

Here’s what that citation refers to:

Wikipedia is not an indiscriminate collection of information

To provide encyclopedic value, data should be put in context with explanations referenced to independent sources. As explained in § Encyclopedic content above, merely being true, or even verifiable, does not automatically make something suitable for inclusion in the encyclopedia. Wikipedia articles should not be:

…

Exhaustive logs of software updates. Use reliable third-party (not self-published or official) sources in articles dealing with software updates to describe the versions listed or discussed in the article. Common sense must be applied regarding the level of detail to include. A list of every version/beta/patch is inappropriate. Consider a summary of development instead.

That all sounds reasonable to me, and even if it didn’t, I’m not an authority on “encyclopedic values”, so my opinion is pretty irrelevant. Besides, I agree that anyone creating new content should make an effort to abide by Wikipedia’s guidelines. However, guidelines evolve over time, so it’s not always clear whether a contributor simply ignored guidelines or their content later fell victim to evolving standards.

And speaking of standards, there seems to be a “double-standard”, because it’s not hard to find other Wikipedia pages on other popular or significant software packages that have their own detailed version history, such as Microsoft Windows or Adobe Photoshop. In fact, the version histories of DOS and Windows are so important that they have their own dedicated pages (see Timeline of DOS operating systems and List of Microsoft Windows versions).

However, my real quibble is not with the guidelines or how loosely they’re followed. What bothers me is the wholesale act of deleting a large amount of information after it has already been created, without making any effort to first summarize that information (as the guidelines specifically suggest) or even alerting the Wikipedia community that there are issues with it.

I’m always seeing notices on Wikipedia pages about the need to improve content, from small “[citation needed]” notations to large banners, like this very notice on the PKZIP page:

“This article relies excessively on references to primary sources. Please improve this article by adding secondary or tertiary sources.”

Those notices are great ways to engage people to help improve the content. What is not a great way is simply deleting the content.

PKZIP Version History (2007-2022)

PKZIP version history was first added to Wikipedia in October 2007 by Jacob Poon and regularly updated by him through 2009. Here’s what it looked like right before it was deleted in late 2022.

PKZIP 0.8 (released on January 1, 1989) initial version
PKZIP 0.9 (released on February 10, 1989) supported reducing algorithm (from SCRNCH by Graeme McRae)[1] with four compression settings and shrinking. In addition to PKZIP and PKUNZIP, it also included ZIP2EXE, a utility for creating a self-extracting archive which required an external self-extracting executable header created by MAKESFX from the PKZIP executable package.
PKZIP 0.92 (released on March 6, 1989): In addition to bug fixes, PKZIP included an option to automatically choose the best compression method for each file. New tools included with PKZIP include PKZipFix.
PKZIP 1.01 (released on July 21, 1989) added Implode compression, while reduced files can only be extracted from ZIP archive. Imploding was chosen based on the characteristics of the file being compressed.[2] New utility included Thomas Atkinson’s REZIP conversion utility (part of ZIP-KIT). PKZIP’s default compression behavior was changed from fastest (Shrink) to best (Implode). Supported platforms include OS/2, DOS.
PKZIP 1.02 (released on October 1, 1989) includes new utility BIOSFIX.COM, which preserved the entire 80386 register set during any mode switches via INT 15H. OS/2 version added ZIP2EXE and 2 self-extracting archive headers.
PKZIP 1.10 (released on March 15, 1990): New features included authenticity verification, “mini” PKSFX self-extracting module, integrating self-extracting module into ZIP2EXE, ability to save & restore volume labels. Imploding was up to 5X faster and compression ratio was improved over 1.02. EAX register was always saved on 80386 or above CPU. Removed tools included BIOSFIX, REZIP, MAKESFX.
PKZIP 1.93a (released in October 1991): An alpha version that introduced a new compression method which Katz called “deflating”. It was supposed to be quickly followed by a final PKZIP 2 release, but there were numerous delays.
PKZIP 2.04g (released in January 1993): By the time the release was ready, fake 2.x releases were circulating, some of them malware, so an untainted version number was chosen instead of 2.0. This new version dispensed with the miscellaneous compression methods of PKZIP 1.x and replaced them with the deflate algorithm (although several levels of deflation were provided by the program). The resulting file format has since become ubiquitous on Microsoft Windows and on the Internet – almost all files with the .ZIP (or .zip) extension are in PKZIP 2.x format, and utilities to read and write these files are available on all common platforms. PKZIP 2.x also supported spanning archives to multiple disk, which simply split the files into multiple pieces, and using volume label on each drive to differentiate each other. A new Authenticity Verification (AV) signature format was used. Registered version included PKUNZJR, PK Safe ANSI, PKCFG utilities.
PKZIP 2.06 was released in 1994. It was a version of PKZIP 2.04g licensed to IBM.[3]
PKZIP 2.50 (released on April 15, 1998) was the first version released for Windows 3.1, 95, NT platforms. DOS version of PKZIP 2.50 was released on 1999-03-01, as its final MS-DOS product. PKZIP 2.50 supported long file names on all builds, and Deflate64 extraction. DCL Implode extraction was supported on non-DOS ports. A new command-line product was introduced in Windows 95, OS/2, UNIX platforms, called “PKZIP Command Line” (later expanded to “PKZIP Server”), which featured new command line syntax.
PKZIP 2.6 was the last version to support Windows 3.1 and Windows NT for the Alpha and PowerPC platforms.
PKZIP 2.70 added email MAPI (i.e. Send To) support. Registered version included creation of configurable self-extracted archives, added Authenticity Verification (AV) Information. Distribution Licensed versions included enhanced self-extractors. Professional distribution licensed version could create self-extracting patch files, and includes self-extractors for several new platforms.
PKZIP 4.0 was an updated version of PKZIP 2.7. Version 3 was skipped as a result of PKZIP 3.0 Trojan.[4] It supported Deflate64 and DCL Implode compression, and the use of X.509 v3 certificate-based authentication.,[5] creation of Span or Split large .ZIP archives. Old PKZIP command line conversion tools were introduced.
On August 21, 2001, PKWARE announced the availability of PKZIP 4.5.[6] PKZIP 4.5 included ZIP64 archives support, which allowed more than 65535 files per ZIP archives, and storing files larger than 4 gigabytes into .ZIP archive. A version called PKZIP Suite 4.5 also included PKZIP Command Line 4.5, PKZIP Explorer 1.5, PKZIP Attachments 1.1, and PKZIP Plug-In 1.0.
PKZIP 5.0 was announced in 2002,[7] which introduced Strong Encryption Specification (SES) for the Professional version of the product, which initially included DES, 3DES, RC2, RC4 encryption formats, and the use of using X.509 v3 certificate-based encryption.
PKZIP 6.0 (released in 2003) added support for bzip2 (based on Burrows–Wheeler transform) compression, with Professional Edition supporting 256-bit AES.[8]
PKZIP 7.0 changed SES to use non-OAEP key wrapping for compatibility with smart cards and USB tokens. Support of creating AV authenticity verification archives was dropped. PKZIP could now create archives of the following types: ZIP, bzip2, GZIP, tar, UUEncoded, XXEncoded.
PKZIP 8.0 was released on April 27, 2004.[9] In addition, PKWARE renamed its PKZip Professional to SecureZIP.[10] Creation of ZIP archives with encrypted headers was available.
PKZIP 9.0 was the first version to unofficially support Windows Vista (as administrator).[11] Creation of RC2, DES-encrypted ZIP archives are dropped.
PKZIP 10 Enterprise Edition and SecureZIP 10 were released on i5/OS. It offered the ability to create ZIP64 archives for the target platform.[12] Desktop PKZIP version was no longer developed beyond version 9.

And yes, I’m well aware that instead of wasting my time on this “rant”, I could create a Wikipedia account, become a contributor, and fix the PKZIP page myself – or at least try to.

And in fact, I did recently create an account on Wikipedia with that thought in mind, but that was just the first step in a long process. After signing up, Wikipedia wanted me to spend a certain amount of time editing other articles first, learning the ropes, reading the guidelines, etc. Perhaps I could have immediately jumped to the PKZIP page and clicked “undo” on the “Version history” deletion, but even if that had been allowed, that seemed a little too passive-aggressive.

It’s much easier for me to just write whatever I want on my own website – adhering at all times to the strictest of guidelines, of course. ;-)

My Own Limited Survey of PKZIP Versions (1989-1993)

On a tangential note, here’s a summary of what I recently learned about PKZIP versions while working through the ibm-wgam-wbiz-collection, which has now been ingested by DiscMaster.

A few versions were missing from Wikipedia’s list, and even a couple were missing from Jason Summers’ list (1.00ß and 2.01).

In all cases, I tried to find downloads that appeared to be close to, if not actual, distribution copies. I have not tried to enumerate all the differences between the versions, although I have included the various WHATSNEW documents that shipped alongside each PKZIP.EXE below.

Version	Dated	Timestamp	Size	Download	MD5 Hash	Contents
PKZIP 0.80 Beta	Jan 10 1989	1989-01-11 05:55:22	23835	PKZ080.ZIP	d13726356d84956cf05faefa3331d468	Contents
PKZIP 0.90	Feb 01 1989	1989-02-10 00:00:00	26334	PKZ090.EXE	8944c0215e7832c93ff77c8274ce5a94	Contents
PKZIP 0.92	Mar 06 1989	1989-03-06 00:00:00	26796	PKZ092.EXE	38d76628b87c1b84e5dd3c50a2d2e3bf	Contents
PKZIP 1.00ß	Jun 30 1989	1989-06-30 18:47:30	30818	PKZ100B.ZIP	31d14f13d9329b1ad5fbaaf664a0ef93	Contents
PKZIP 1.01	Jul 21 1989	1989-07-21 01:01:00	31342	PKZ101.EXE	36408e97e694cd17b12c3e3bfdac2a71	Contents
PKZIP 1.02	Oct 01 1989	1989-10-01 01:02:00	31408	PKZ102.EXE	6e762ea5460dcaae43b73a6ec51e50cc	Contents
PKZIP 1.10	Mar 15 1990	1990-03-15 01:10:00	34296	PKZ110.EXE	5036d372ac010331a78071a574354cf0	Contents
PKZIP 1.93 Alpha	Oct 15 1991	1991-10-15 19:30:00	24411	PKZ193A.EXE	0ece8648324cafda50549ca040421fc5	Contents
PKZIP 2.01	Mar 15 1992	1992-03-15 02:01:00	24869	PKZ201.ZIP	b2d208014330d764510bdc54de3a51fd	Contents
PKZIP 2.04c	Dec 28 1992	1992-12-28 02:04:12	41462	PKZ204C.EXE	60de53bc608d662f02bf8037e302e337	Contents
PKZIP 2.04e	Jan 25 1993	1993-01-25 02:04:14	42475	PKZ204E.EXE	fe72c498c1012fca65055250d90802e9	Contents
PKZIP 2.04g	Feb 01 1993	1993-02-01 02:04:16	42166	PKZ204G.EXE	e5a48751250ffa94a8cf2ecaf8073098	Contents

Other PKZIP.EXE variations included versions licensed to Microsoft and IBM, such as:

Version	Dated	Timestamp	Size	Download	MD5 Hash	Contents
PKZIP 1.1 [MS]	Nov 10 1990	1990-11-10 00:00:02	23509	PKZIP.EXE	901ddd289e845024511ce19eafb16870	Contents
PKZIP 1.11 [IBM]	Nov 23 1990	1990-11-23 00:00:00	23458	PKZIP.EXE	caf3d28e4e27628a28e97a238780d72a	Contents

PKZIP 0.80 Beta

pc.js v3.00
Copyright © 2012-2026 Jeff Parsons <Jeff@pcjs.org>
Options: --disk=https://harddisks.pcjs.org/pcx86/10mb/MSDOS330-C400.json --diskette=http://cd.textfiles.com/originalsw/25/pkz080.zip
[Press CTRL-D to enter command mode]

A:\>DIR

 Volume in drive A has no label
 Directory of  A:\

ARC2ZIP  EXE    11776   1-25-89   5:32p
BETA     DOC    12420   1-10-89   7:39p
BUGREP   DOC     1270   1-11-89  12:12a
DISCLAIM DOC     1622   1-11-89  12:15a
EXTRACT  DOC     5382   1-11-89  12:25a
FORMAT   DOC     7395   1-11-89  12:15a
HOW2USE  TXT     3069   1-25-89  10:42p
PKUNZIP  EXE    16003   1-10-89  11:21p
PKZIP    EXE    23835   1-11-89   5:55a
SDK      DOC     1372   1-11-89   6:38p
       10 File(s)     73728 bytes free

A:\>PKZIP

PKZIP   Create/Update Utility   Version 0.80 Beta   1-10-89
Copyright 1989 PKWARE Inc.  All Rights Reserved.  Not For Distribution.

See Beta documentation for help.

Beta Version - Please do not distribute!

PKWARE hereby disclaims all warranties relating to this software, whether
express or implied, including without limitation any implied warranties of
merchantability or fitness for a particular purpose. PKWARE will not be liable
for any special, incidental, consequential, indirect or similar damages due to
loss of data or any other reason, even if PKWARE or an agent of PKWARE has
been advised of the possibility of such damages.  In no event shall PKWARE's
liability for any damages ever exceed the price paid for the license to use
software, regardless of the form of the claim.  The person using the software
bears all risk as to the quality and performance of the software.

PKZIP 0.90

pc.js v3.00
Copyright © 2012-2026 Jeff Parsons <Jeff@pcjs.org>
Options: --disk=https://harddisks.pcjs.org/pcx86/10mb/MSDOS330-C400.json --diskette=http://cd.textfiles.com/originalsw/25/pkz090.exe
[Press CTRL-D to enter command mode]

A:\>DIR

 Volume in drive A has no label
 Directory of  A:\

README   DOC      535   2-10-89
RELEASE  DOC      307   2-10-89
MANUAL   DOC    73345   2-10-89
ORDER    DOC     5729   2-10-89
DEDICATE DOC      718   2-10-89
APPNOTE  TXT    13715   2-10-89
PKZIP    EXE    26334   2-10-89
PKUNZIP  EXE    18034   2-10-89
ZIP2EXE  EXE     6674   2-10-89
MAKESFX  COM      846   2-10-89
       10 File(s)     10752 bytes free

A:\>PKZIP

PKZIP (tm)   FAST!   Create/Update Utility   Version 0.90   02-01-89
Copyright 1989 PKWARE Inc.  All Rights Reserved.  PKZIP/h for help

Usage: PKZIP [-b[path]] [options] zipfile [@list] [files...]
Options are:
  -a = add files to zipfile         -b = create tmp zipfile on alternate drive
  -d = delete files from zipfile    -f = freshen files in zipfile
  -i = add changed files to zipfile -l = display software license
  -u = update files to zipfile      -z = add zipfile comment
  -v[t] = view files in zipfile [with long technical info]
  -m = move files to zipfile (can be combined with A,F,U options)
  -r = recurse subdirectories       -p = store pathnames in zipfile
  -e[a,b][n] = use extra compression on [Ascii,Binary] files with
       compression factor of N.  Default factor is 2 if not given.
zipfile = ZIP file name, wildcards *,? ok.  Default extension is .ZIP
file    = Name(s) of files to compress. Wildcards *,? ok. Default is ALL files.

If you find PKZIP fast, easy, and convenient to use, a registration of $25
would be appreciated.  If you send $47 or more you will receive, when
available, the next version of the PKZIP, PKUNZIP, and PKSFX programs.
Please state the version of the software that you currently have.  Send
check or money order to:   PKWARE, Inc.
                           7545 N. Port Washington Rd.
                           Glendale, WI 53217

PKZIP 0.92

pc.js v3.00
Copyright © 2012-2026 Jeff Parsons <Jeff@pcjs.org>
Options: --disk=https://harddisks.pcjs.org/pcx86/10mb/MSDOS330-C400.json --diskette=http://cd.textfiles.com/originalsw/25/pkz092.exe
[Press CTRL-D to enter command mode]

A:\>DIR

 Volume in drive A has no label
 Directory of  A:\

MANUAL   DOC    73345   2-10-89
OMBUDSMN ASP      592   3-06-89
ORDER    DOC     7253   3-06-89
DEDICATE DOC      718   2-10-89
APPNOTE  TXT    13715   2-10-89
PKZIPFIX DOC     2434   2-23-89
PKZIPFIX EXE     8388   2-23-89
MAKESFX  COM      846   3-06-89
ZIP2EXE  EXE     6686   3-06-89
PKZIP    EXE    26796   3-06-89
PKUNZIP  EXE    18208   3-06-89
VER092   DOC     2920   3-06-89
RELEASE  DOC      307   3-06-89
README   DOC      535   3-06-89
       14 File(s)    152576 bytes free

A:\>PKZIP

PKZIP (tm)   FAST!   Create/Update Utility   Version 0.92   03-06-89
Copyright 1989 PKWARE Inc.  All Rights Reserved.  PKZIP/h for help

Usage: PKZIP [-b[path]] [options] zipfile [@list] [files...]
Options are:
  -a = add files             -b = create tmp zipfile on alternate drive
  -d = delete files          -f = freshen files    -i = add changed files
  -l = display license info  -u = update files     -z = add zipfile comment
  -m[u,f] = move files       -r = recurse subdirs  -p = store pathnames
  -v[t] = view files [with long technical information]
  -e[a,b][n] = use extra compression on [Ascii,Binary] files with
       compression factor of N, (1-4).  Default factor is 2 if not given.
  -ex = use maximum optimal compression on all files.

zipfile = ZIP file name.  Default extension is .ZIP
file    = Names of files to compress. Wildcards *,? ok. Default is ALL files.

If you find PKZIP fast, easy, and convenient to use, a registration of $25
would be appreciated.  If you send $47 or more you will receive, when
available, the next version of the PKZIP, PKUNZIP, and PKSFX programs.
Please state the version of the software that you currently have.  Send
check or money order to:   PKWARE, Inc.
                           7545 N. Port Washington Rd.
                           Glendale, WI 53217

PKZIP 1.00ß

pc.js v3.00
Copyright © 2012-2026 Jeff Parsons <Jeff@pcjs.org>
Options: --disk=https://harddisks.pcjs.org/pcx86/10mb/MSDOS330-C400.json --diskette=https://discmaster.textfiles.com/file/29986/wbiz0020-0029/wbiz0021.tar/wbiz0021/PKZ100B.ZIP
[Press CTRL-D to enter command mode]

A:\>DIR

 Volume in drive A has no label
 Directory of  A:\

MANUAL   DOC    86718   6-30-89   6:47p
PKZIP    EXE    30818   6-30-89   6:47p
PKUNZIP  EXE    21396   6-30-89   6:47p
APPNOTE  TXT    20951   6-30-89   6:47p
        4 File(s)    160768 bytes free

A:\>PKZIP

PKZIP (tm)   FAST!   Create/Update Utility   Version 1.0ß   06-30-89
Copyright 1989 PKWARE Inc.   All Rights Reserved.   DO NOT DISTRIBUTE!

Usage: PKZIP [-b[path]] [options] zipfile [@list] [files...]
Options are:
  -d = delete files           -f = freshen files     -i = add changed files
  -l = display license info   -u = update files      -m[u,f] = move files
  -a = add files              -b = create temp zipfile on alternate drive
  -c = add/edit file comments -C = add comments to new files only
 -es = use fast compression  -ex = use maximal compression (default)
  -k = keep same ZIP date     -o = set ZIP date to latest file
  -q = enable ANSI comments   -s<pwd> = Scramble files with password
  -p = store pathnames recursed into                 -r = recurse subdirs
  -P = store pathnames specified & recursed into     -z = add zipfile comment
  -w<H,S> = include Hidden/System files       -x<filespec> = eXclude filespec
  -W<H,S> = don't include Hidden/System files (default)
  -j<H,S,R> = mask Hidden/System/Readonly attributes when adding files
  -J<H,S,R> = don't mask Hidden/System/Readonly attributes when adding files
  -v[b,c,d,e,n,p,s,r,t] = view ZIP(s) [Brief listing/show Comments/sort by -
    Date/Ext/Name/Percentage/Size/sort Reverse/Technical (long) listing]

zipfile = ZIP file name.  Default extension is .ZIP
file    = Names of files to compress. Wildcards *,? ok. Default is ALL files.
@list   = listfile containing names of files to add or view etc.
                         
If you find PKZIP fast, easy, and convenient to use, a registration of $25
would be appreciated.  If you send $47 or more you will receive, when
available, the next version of the PKZIP, PKUNZIP, and PKSFX programs.
Please state the version of the software that you currently have.  Send
check or money order to:   PKWARE, Inc.
                           7545 N. Port Washington Rd.
                           Glendale, WI 53217

PKZIP 1.01

pc.js v3.00
Copyright © 2012-2026 Jeff Parsons <Jeff@pcjs.org>
Options: --disk=https://harddisks.pcjs.org/pcx86/10mb/MSDOS330-C400.json --diskette=http://cd.textfiles.com/originalsw/25/pkz101.exe
[Press CTRL-D to enter command mode]

A:\>DIR

 Volume in drive A has no label
 Directory of  A:\

README   DOC      873   7-21-89   1:01a
MANUAL   DOC   140355   7-21-89   1:01a
DEDICATE DOC      720   7-21-89   1:01a
LICENSE  DOC     8959   7-21-89   1:01a
ORDER    DOC     4607   7-21-89   1:01a
APPNOTE  TXT    25662   7-21-89   1:01a
OMBUDSMN ASP      595   7-21-89   1:01a
PKZIP    EXE    31342   7-21-89   1:01a
PKUNZIP  EXE    21440   7-21-89   1:01a
MAKESFX  COM      896   7-21-89   1:01a
ZIP2EXE  EXE     6898   7-21-89   1:01a
PKZIPFIX EXE     8926   7-21-89   1:01a
REZIP    ZIP    14592   7-21-89   1:01a
       13 File(s)     51200 bytes free

A:\>PKZIP

PKZIP (tm)   FAST!   Create/Update Utility   Version 1.01   07-21-89
Copyright 1989 PKWARE Inc.   All Rights Reserved.   PKZIP/h for help

Usage: PKZIP [-b[path]] [options] zipfile [@list] [files...]
Options are:
  -d = delete files           -f = freshen files     -i = add changed files
  -l = display license info   -u = update files      -m[u,f] = move files
  -a = add files              -b = create temp zipfile on alternate drive
  -c = add/edit file comments -C = add comments to new files only
 -es = use fast compression  -ex = use maximal compression (default)
  -k = keep same ZIP date     -o = set ZIP date to latest file
  -q = enable ANSI comments   -s<pwd> = Scramble files with password
  -p = store pathnames recursed into                 -r = recurse subdirs
  -P = store pathnames specified & recursed into     -z = add zipfile comment
  -w<H,S> = include Hidden/System files       -x<filespec> = eXclude filespec
  -W<H,S> = don't include Hidden/System files (default)
  -j<H,S,R> = mask Hidden/System/Readonly attributes when adding files
  -J<H,S,R> = don't mask Hidden/System/Readonly attributes when adding files
  -v[b,c,d,e,n,p,s,r,t] = view ZIP(s) [Brief listing/show Comments/sort by -
    Date/Ext/Name/Percentage/Size/sort Reverse/Technical (long) listing]

zipfile = ZIP file name.  Default extension is .ZIP
file    = Names of files to compress. Wildcards *,? ok. Default is ALL files.
@list   = listfile containing names of files to add or view etc.
                         
If you find PKZIP fast, easy, and convenient to use, a registration of $25
would be appreciated.  If you send $47 or more you will receive, when
available, the next version of the PKZIP, PKUNZIP, and PKSFX programs.
Please state the version of the software that you currently have.  Send
check or money order to:   PKWARE, Inc.
                           7545 N. Port Washington Rd.
                           Glendale, WI 53217

PKZIP 1.02

pc.js v3.00
Copyright © 2012-2026 Jeff Parsons <Jeff@pcjs.org>
Options: --disk=https://harddisks.pcjs.org/pcx86/10mb/MSDOS330-C400.json --diskette=https://discmaster.textfiles.com/file/11833/sdf.org.zip/sdf.org/pub/computers/pcjr/arc/PKZ102.EXE
[Press CTRL-D to enter command mode]

A:\>DIR

 Volume in drive A has no label
 Directory of  A:\

WHATSNEW 102     5837  10-01-89   1:02a
BIOSFIX  COM      295  10-01-89   1:02a
README   DOC      873  10-01-89   1:02a
MANUAL   DOC   140355   7-21-89   1:01a
DEDICATE DOC      720   7-21-89   1:01a
LICENSE  DOC     8959   7-21-89   1:01a
ORDER    DOC     4607   7-21-89   1:01a
APPNOTE  TXT    25662   7-21-89   1:01a
OMBUDSMN ASP      595   7-21-89   1:01a
PKZIP    EXE    31408  10-01-89   1:02a
PKUNZIP  EXE    22022  10-01-89   1:02a
MAKESFX  COM      896  10-01-89   1:02a
ZIP2EXE  EXE     6906  10-01-89   1:02a
PKZIPFIX EXE     8926   7-21-89   1:01a
REZIP    ZIP    14592  10-01-89   1:02a
       15 File(s)     43008 bytes free

A:\>PKZIP

PKZIP (tm)   FAST!   Create/Update Utility   Version 1.02   10-01-89
Copyright 1989 PKWARE Inc.   All Rights Reserved.   PKZIP/h for help

Usage: PKZIP [-b[path]] [options] zipfile [@list] [files...]
Options are:
  -d = delete files           -f = freshen files     -i = add changed files
  -l = display license info   -u = update files      -m[u,f] = move files
  -a = add files              -b = create temp zipfile on alternate drive
  -c = add/edit file comments -C = add comments to new files only
 -es = use fast compression  -ex = use maximal compression (default)
  -k = keep same ZIP date     -o = set ZIP date to latest file
  -q = enable ANSI comments   -s<pwd> = Scramble files with password
  -p = store pathnames recursed into                 -r = recurse subdirs
  -P = store pathnames specified & recursed into     -z = add zipfile comment
  -w<H,S> = include Hidden/System files       -x<filespec> = eXclude filespec
  -W<H,S> = don't include Hidden/System files (default)
  -j<H,S,R> = mask Hidden/System/Readonly attributes when adding files
  -J<H,S,R> = don't mask Hidden/System/Readonly attributes when adding files
  -v[b,c,d,e,n,p,s,r,t] = view ZIP(s) [Brief listing/show Comments/sort by -
    Date/Ext/Name/Percentage/Size/sort Reverse/Technical (long) listing]

zipfile = ZIP file name.  Default extension is .ZIP
file    = Names of files to compress. Wildcards *,? ok. Default is ALL files.
@list   = listfile containing names of files to add or view etc.
                         
If you find PKZIP fast, easy, and convenient to use, a registration of $25
would be appreciated.  If you send $47 or more you will receive, when
available, the next version of the PKZIP, PKUNZIP, and PKSFX programs.
Please state the version of the software that you currently have.  Send
check or money order to:   PKWARE, Inc.
                           7545 N. Port Washington Rd.
                           Glendale, WI 53217

A:\>TYPE WHATSNEW.102
Version 1.02 is a minor bug fix for version 1.01 of PKZIP,
PKUNZIP, and ZIP2EXE for the MS-DOS software; and PKSFX and
ZIP2EXE for the OS/2 software.  No new features have been added
to the software in this release.

Those who have registered version 1.0x and are due a free
upgrade will receive PKZIP/PKUNZIP/PKSFX(R) etc. version 1.1,
with manual, when it becomes avaliable.


MS-DOS
======

New files:  PKZIP.EXE, PKUNZIP.EXE, ZIP2EXE.EXE, BIOSFIX.COM
            REZIP.ZIP, MAKESFX.COM

All other files are the same as for version 1.01.

Description of changes
----------------------

  o An updated version of Thomas Atkinson's REZIP is included
    with this version, that properly handles paths stored
    within a .ZIP file.

  o Several people have reported problems with PKZIP/PKUNZIP
    1.01 on 80386 computers, especially with disk caching
    programs using EXTended memory, such as Super PC-Kwik.
    This is due to the fact that Super PC-Kwik will access
    '80286 extended memory' during the timer interrupt via
    the BIOS interrupt 15H.  However, this corrupts the 32-bit
    accumulator (EAX) in the 80386 CPU, and neither many BIOS's
    nor PC-Kwik bother to preserve the EAX register.  If you have
    an 80386 CPU and have had problems with PKZIP/PKUNZIP 1.01,
    try these work-arounds, in the following order:

    - Run BIOSFIX.COM supplied with version 1.02.  BIOSFIX
      is a small (288 bytes resident) TSR program that preserves
      the entire 80386 register set during any mode switches via
      INT 15H.  This has been tested with Super PC-Kwik, and
      should work with other programs that may be performing
      asynchronouos CPU mode switching.

    - Use an 80386 memory manager such as QEMM or 386^MAX which
      will control and preserve the 80386 machine state.  Also,
      use exPANded memory with your application instead of
      exTENded memory, if possible.

    - If you are using Super PC-Kwik, place /H- /D- on the
      SUPERPCK command line.

    - SET the environment variable PKNO386=xxxx where "xxxx"
      is any string you want.  If the string PKNO386 is present
      in the environment, then PKZIP/PKUNZIP 1.02 will not use
      80386 instructions or registers.  Note however that
      disabling the 80386 usage will make PKZIP run up to 20%
      slower and PKUNZIP up to 40% slower than if the 80386
      instructions are used.

  o Using the "-c" option with PKZIP 1.01 could, in very rare
    instances, cause random corruption of the .ZIP file.  This
    was due to an anomoly in the MSC _ffree() function when
    passed a canonical pointer.  This has been corrected in
    PKZIP 1.02.

  o There is bug in MS-DOS 3.3 and 4.x when SHARE is loaded and
    I/O redirection is used, that sometimes prevents a file or
    device, once redirected to, from ever being opened in a
    sharing mode.  This would cause PKUNZIP to display the message 
    "can't open: NUL" when using the "-t" test option.  PKUNZIP 1.02
    first tries to open NUL in share-deny-none mode, and if that
    fails, it will open the NUL device in compatibility mode,
    bypassing SHARE.

  o ZIP2EXE 1.01 could, on occasion, erroneously report that the
    .ZIP file it was converting contained Reduced files.  This has
    been corrected in this release.

  o When PKZIP 1.01 would be unable to open a file that it was
    trying to compress (it is locked by another program on a
    network, for example) PKZIP would display a message that
    the file could not be added.  However, when PKZIP terminated
    it would exit with an exit code of 0 in this circumstance.
    Several people have requested a way of determining this
    condition when run from a program or batch file, so PKZIP 1.02
    will exit with an errorlevel of 18 when it is unable to open
    one or more files that were specified.  It should be noted that
    this is a 'warning' condition only, and that otherwise PKZIP
    was able to construct the .ZIP file without any errors.


OS/2
====

New files:  PKSFX2.PRG, PKSFXF.PRG, ZIP2EXE.EXE

All other files are the same as for version 1.01.

Description of changes
----------------------

  o The same condition reported above for ZIP2EXE could also
    occur with the OS/2 version of ZIP2EXE.

  o The PKSFX2 and PKSFXF programs would fail if the self-
    extracting file contained more than approximately 50 files.
    This was due to an anomoly between memory allocation under
    MS-DOS vs OS/2, and has been corrected in this release.

Some Common Questions & Answers
-------------------------------

o Where is my copy of PKSFX??  I ran PKZ102.EXE, but I don't have 
  the third program, PKSFX.
  
  - You have to run the program MAKESFX to create the file PKSFX.PRG.

o Why is the new version of PKZIP so much slower than my earlier version?

  - PKZIP version 0.90 or 0.92 defaulted to its fastest compression
    method, called Shrinking.  PKZIP 1.0 defaults to its best
    compressing, albeit slower method called Imploding.  Imploding
    typically compresses much better than Shrinking.  However, you can
    still tell PKZIP 1.02 to perform Shrinking if you want by specifying
    "-es" on the PKZIP command line, or by placing COMPRESS=SPEED in
    your PKZIP.CFG file.  See MANUAL.DOC for more information about
    specifying what compression method is to be used with PKZIP.

o Do I have to convert the .ZIP files I made with earlier version of PKZIP?

  - No, PKZIP and PKUNZIP 1.02 can read and extract .ZIP files created
    by any version of the software.  However, converting .ZIP files
    created by PKZIP 0.92 with the new software can result in additional
    compression.

PKZIP 1.10

pc.js v3.00
Copyright © 2012-2026 Jeff Parsons <Jeff@pcjs.org>
Options: --disk=https://harddisks.pcjs.org/pcx86/10mb/MSDOS330-C400.json --diskette=https://discmaster.textfiles.com/file/17384/TheUltimateSharewareCollect.cdr/ut/ut037.zip/PKZ110.EXE
[Press CTRL-D to enter command mode]

A:\>DIR

 Volume in drive A has no label
 Directory of  A:\

WHATSNEW 110     2916   3-15-90   1:10a
README   DOC      800   3-15-90   1:10a
MANUAL   DOC   140355   7-21-89   1:01a
ADDENDUM DOC    21473   3-15-90   1:10a
DEDICATE DOC      720   3-15-90   1:10a
LICENSE  DOC     9366   3-15-90   1:10a
ORDER    DOC     4701   3-15-90   1:10a
APPNOTE  TXT    25811   3-15-90   1:10a
AUTHVERI FRM     1744   3-15-90   1:10a
OMBUDSMN ASP      595   3-15-90   1:10a
PKZIP    EXE    34296   3-15-90   1:10a
PKUNZIP  EXE    23528   3-15-90   1:10a
ZIP2EXE  EXE    22188   3-15-90   1:10a
PKZIPFIX EXE     9224   3-15-90   1:10a
PUTAV    EXE     4479   3-15-90   1:10a
       15 File(s)     13312 bytes free

A:\>PKZIP

PKZIP (R)   FAST!   Create/Update Utility   Version 1.1   03-15-90
Copr. 1989-1990 PKWARE Inc.  All Rights Reserved.  PKZIP/h for help
PKZIP Reg. U.S. Pat. and Tm. Off.

Usage: PKZIP [-b[path]] [options] zipfile [@list] [files...]
Options summary - consult the PKWARE documentation for additional information
  -x<filespec|@list> = eXclude filespec(s)            -z = add zipfile comment
  -d = delete files            -f = freshen files     -i = add changed files
  -l = display license info    -u = update files      -m[u,f] = move files
  -a = add files               -b = create temp zipfile on alternate drive
  -c = add/edit file comments  -C = add comments to new files only
  -k = keep same ZIP date      -o = set ZIP date to latest file
  -q = enable ANSI comments    -s<pwd> = Scramble files with password
  -r = recurse subdirs         -$[drive] = save volume label 
  -t[mmddyy] = Compress files on or after specified date (default=today)
  -e[x,i,s] = use maXimal compression/Implode only/Shrink only
  -<p|P> = store pathnames | p=recursed into | P=specified & recursed into
  -<w|W><H,S> = | w=include | W=don't include | Hidden/System files
  -<j|J><H,S,R> = | j=mask | J=don't mask | Hidden/System/Readonly attributes
  -v[b,c,d,e,n,p,s,r,t] = view ZIP [Brief listing/show Comments/sort by -
    Date/Ext/Name/Percentage/Size/sort Reverse/Technical (long) listing]
zipfile = ZIP file name.  Default extension is .ZIP
file    = Names of files to compress. Wildcards *,? ok. Default is ALL files.
@list   = listfile containing names of files to add or view etc.
                         
If you find PKZIP fast, easy, and convenient to use, a registration of $25
would be appreciated.  If you send $47 or more you will receive, when
available, the next version of the PKZIP, PKUNZIP, and PKSFX programs.
Please state the version of the software that you currently have.  Send
check or money order to:   PKWARE, Inc.
                           7545 N. Port Washington Rd.
                           Glendale, WI 53217

A:\>TYPE WHATSNEW.110

Several new features have been added to PKZIP/PKUNZIP/PKSFX
version 1.1.  Read the file ADDENDUM.DOC for a complete
description of these changes and enhancements.  Highlights
of PKZIP/PKUNZIP/PKSFX etc. version 1.1 include:

- PKZIP 1.1 Imploding is up to 5X faster, particularly on large
  spreadsheet and database type files where PKZIP 1.02 would run
  relatively slowly.  Most 'typical' types of files should
  implode 5% to 25% faster.  In addition, compression has been
  improved over version 1.02 as well.

- Authenticity Verification.

- A 2,934 byte "mini" PKSFX self-extracting module.

- ZIP2EXE no longer requires the external file PKSFX.PRG.

- The ability to save & restore volume labels.

- Defensive use of the 32 bit accumulator EAX on 80386 or 80486
  computers. In many instances, such as when using MultiSoft's
  PC-KWIK cache or Novell non-dedicated NetWare software, if you
  needed to set the PKNO386 environment variable with
  PKZIP/PKUNZIP version 1.02, you probably don't need to set this
  anymore with PKZIP/PKUNZIP version 1.1.

  There appear to be many programs that use exTENded memory
  and/or '80286 protected mode' that have absolutely no regard to
  saving or restoring the EAX register when switching to and from
  protected mode on an 80386 or 80486 CPU.  There were no bugs in
  PKZIP/PKUNZIP 1.02 regarding usage of the 80386 instructions or
  registers.  However, PKZIP/PKUNZIP 1.02 did not expect that the
  EAX register would be wantonly corrupted from one instruction
  to the next.  PKZIP/PKUNZIP 1.1 do expect that other programs
  may randomly destroy the EAX register, and defends against
  this.  PKZIP/PKUNZIP 1.1 treat all references to EAX as a
  critical section, briefly disallowing programs from
  interrupting PKZIP/PKUNZIP when the EAX register is used.

  If it sounds ludicrous that a program would need to protect
  access to a CPU register like this, particularly the
  accumulator, that's because it is!  Considering that 80386
  computers have commonly been available for over two years now,
  it is unfortunate that many '80286 specific' programs don't
  have any consideration that they could be running on an 80386
  or 80486 CPU.  It takes approximately 30 bytes of code for a
  program to determine if it is running on an 80286 CPU versus an
  80386/80486 CPU, and two instructions (namely PUSH EAX and POP
  EAX) to save and restore the EAX register.  Any program that
  uses exTENded memory or 80286 protected mode has little excuse
  not to save and restore EAX when running on an 80386 or 80486
  CPU, especially if they are going to interrupt the currently
  executing program!  Programs that are negligent of this will
  only cause additional problems in the future as more software
  is developed to take advantage of the 80386 and 80486
  instruction sets and 32-bit registers.

PKZIP 1.1 [MS]

pc.js v3.00
Copyright © 2012-2026 Jeff Parsons <Jeff@pcjs.org>
Options: --disk=https://harddisks.pcjs.org/pcx86/10mb/MSDOS330-C400.json --diskette=https://discmaster.textfiles.com/file/29651/ibm0330-0339/ibm0333.tar/ibm0333/MSONLIN2.ZIP
[Press CTRL-D to enter command mode]

A:\>DIR

 Volume in drive A has no label
 Directory of  A:\

ABORT    DIA       75  11-10-92  12:00a
HAYESOFF DIA      597  11-10-92  12:00a
HAYESON  DIA     2881  11-10-92  12:00a
ISAMREPR DLL   101100  11-10-92  12:00a
LOGOFF   DIA      684  11-10-92  12:00a
LOGON    DIA     2685  11-10-92  12:00a
PKUNZIP  EXE    16622  11-10-92  12:00a
PKZIP    EXE    23509  11-10-92  12:00a
PKZIP10  TXT   122513  11-10-92  12:00a
PKZIP11  TXT    16587  11-10-92  12:00a
PKZIPFIX EXE     7523  11-10-92  12:00a
FILE_ID  DIZ       47   4-20-95   8:30p
       12 File(s)     21504 bytes free

A:\>PKZIP

PKZIP (R)   FAST!   Create/Update Utility   Version 1.1   03-15-90
Copr. 1989-1990 PKWARE Inc.  All Rights Reserved.  PKZIP/h for help
PKZIP Reg. U.S. Pat. and Tm. Off.

Usage: PKZIP [-b[path]] [options] zipfile [@list] [files...]
Options summary - consult the PKWARE documentation for additional information
  -x<filespec|@list> = eXclude filespec(s)            -z = add zipfile comment
  -d = delete files            -f = freshen files     -i = add changed files
  -l = display license info    -u = update files      -m[u,f] = move files
  -a = add files               -b = create temp zipfile on alternate drive
  -c = add/edit file comments  -C = add comments to new files only
  -k = keep same ZIP date      -o = set ZIP date to latest file
  -q = enable ANSI comments    -s<pwd> = Scramble files with password
  -r = recurse subdirs         -$[drive] = save volume label 
  -t[mmddyy] = Compress files on or after specified date (default=today)
  -e[x,i,s] = use maXimal compression/Implode only/Shrink only
  -<p|P> = store pathnames | p=recursed into | P=specified & recursed into
  -<w|W><H,S> = | w=include | W=don't include | Hidden/System files
  -<j|J><H,S,R> = | j=mask | J=don't mask | Hidden/System/Readonly attributes
  -v[b,c,d,e,n,p,s,r,t] = view ZIP [Brief listing/show Comments/sort by -
    Date/Ext/Name/Percentage/Size/sort Reverse/Technical (long) listing]
zipfile = ZIP file name.  Default extension is .ZIP
file    = Names of files to compress. Wildcards *,? ok. Default is ALL files.
@list   = listfile containing names of files to add or view etc.
                         
This copy of PKZIP has been licensed to Microsoft Corporation for
distribution to Microsoft customers.

PKZIP 1.11 [IBM]

pc.js v3.00
Copyright © 2012-2026 Jeff Parsons <Jeff@pcjs.org>
Options: --disk=https://harddisks.pcjs.org/pcx86/10mb/MSDOS330-C400.json --diskette=https://discmaster.textfiles.com/file/29622/ibm0040-0049/ibm0040.tar/ibm0040/W3DRV12.ZIP
[Press CTRL-D to enter command mode]

A:\>DIR

 Volume in drive A has no label
 Directory of  A:\

PKZIP    EXE    23458  11-23-90
DRVRDSK1 ZIP   362246  10-16-91  11:02a
DRVRDSK2 ZIP   324181  10-16-91  11:04a
        3 File(s)    503296 bytes free

A:\>PKZIP

PKZIP (R)   FAST!   Create/Update Utility   Version 1.11  11-23-90
Copr. 1989-1990 PKWARE Inc.  All Rights Reserved.  PKZIP/h for help
PKZIP Reg. U.S. Pat. and Tm. Off.    IBM LICENSED VERSION

Usage: PKZIP [-b[path]] [options] zipfile [@list] [files...]
Options summary - consult the PKWARE documentation for additional information
  -x<filespec|@list> = eXclude filespec(s)            -z = add zipfile comment
  -d = delete files            -f = freshen files     -i = add changed files
  -l = display license info    -u = update files      -m[u,f] = move files
  -a = add files               -b = create temp zipfile on alternate drive
  -c = add/edit file comments  -C = add comments to new files only
  -k = keep same ZIP date      -o = set ZIP date to latest file
  -q = enable ANSI comments
  -r = recurse subdirs         -$[drive] = save volume label 
  -t[mmddyy] = Compress files on or after specified date (default=today)
  -e[x,i,s] = use maXimal compression/Implode only/Shrink only
  -<p|P> = store pathnames | p=recursed into | P=specified & recursed into
  -<w|W><H,S> = | w=include | W=don't include | Hidden/System files
  -<j|J><H,S,R> = | j=mask | J=don't mask | Hidden/System/Readonly attributes
  -v[b,c,d,e,n,p,s,r,t] = view ZIP [Brief listing/show Comments/sort by -
    Date/Ext/Name/Percentage/Size/sort Reverse/Technical (long) listing]
zipfile = ZIP file name.  Default extension is .ZIP
file    = Names of files to compress. Wildcards *,? ok. Default is ALL files.
@list   = listfile containing names of files to add or view etc.
                         
PKWARE, Inc.
7545 N. Port Washington Rd.
Glendale, WI 53217

PKZIP 1.93 ALPHA

pc.js v3.00
Copyright © 2012-2026 Jeff Parsons <Jeff@pcjs.org>
Options: --disk=https://harddisks.pcjs.org/pcx86/10mb/MSDOS330-C400.json --diskette=https://discmaster.textfiles.com/file/29622/ibm0040-0049/ibm0044.tar/ibm0044/PKZ193A.EXE
[Press CTRL-D to enter command mode]

A:\>DIR

 Volume in drive A has no label
 Directory of  A:\

ALPHA193 DOC     9299  10-15-91   7:30p
BUGREP   DOC     2275  10-15-91   7:30p
BENCH    DOC     2449  10-15-91   7:30p
PKZIP    EXE    24411  10-15-91   7:30p
PKUNZIP  EXE    19411  10-15-91   7:30p
APPNOTE  TXT    32227  10-15-91   7:30p
CRC      DOC     1547  10-15-91   7:30p
        7 File(s)     67072 bytes free

A:\>PKZIP

PKZIP (R)  FAST!  Create/Update Utility  Version 1.93  ALPHA  10-15-91
Copr. 1989-1991 PKWARE Inc.  All Rights Reserved.  PKZIP/h for help
PKZIP Reg. U.S. Pat. and Tm. Off.   Patent No. 5,051,745

Usage: PKZIP [-b[path]] [options] zipfile [@list] [files...]
Options summary - consult the PKWARE documentation for additional information
  -x<filespec|@list> = eXclude filespec(s)            -z = add zipfile comment
  -d = delete files            -f = freshen files     -i = add changed files
  -l = display license info    -u = update files      -m[u,f] = move files
  -a = add files               -b = create temp zipfile on alternate drive
  -c = add/edit file comments  -C = add comments to new files only
  -k = keep same ZIP date      -o = set ZIP date to latest file
  -q = enable ANSI comments    -s<pwd> = Scramble files with password
  -r = recurse subdirs         -$[drive] = save volume label
  -<T|t>[mmddyy] = Compress files before|after specified date (default=today)
  -e[x,n,s] = maXimal compression/Normal compression/Speed(fast) compression
  -<p|P> = store pathnames | p=recursed into | P=specified & recursed into
  -<w|W><H,S> = | w=include | W=don't include | Hidden/System files
  -<j|J><H,S,R> = | j=mask | J=don't mask | Hidden/System/Readonly attributes
  -v[b,c,d,e,n,p,s,r,t] = view ZIP [Brief listing/show Comments/sort by -
    Date/Ext/Name/Percentage/Size/sort Reverse/Technical (long) listing]
zipfile = ZIP file name.  Default extension is .ZIP
file    = Names of files to compress. Wildcards *,? ok. Default is ALL files.
@list   = listfile containing names of files to add or view etc.
                         
NOTICE: THIS IS PRE-RELEASE SOFTWARE AND, AS SUCH, HAS NOT BEEN COMPLETELY
TESTED.  PERSONS USING THIS SOFTWARE MAY ENCOUNTER PROBLEMS AND IT IS LIKELY
THAT YOU MAY LOSE OR DESTROY DATA.  YOU MUST BACKUP YOUR SYSTEM PRIOR
TO USING THIS SOFTWARE, AND SHOULD DO SO OFTEN DURING SUBSEQUENT USE.

PKWARE, Inc.
9025 N. Deerwood Drive
Brown Deer, WI 53223

A:\>TYPE ALPHA193.DOC
Copyright 1989-1991 PKWARE Inc.  All Rights Reserved.

NOTICE
------

  THIS IS PRE-RELEASE SOFTWARE AND, AS SUCH, HAS NOT BEEN COMPLETELY
  TESTED. PERSONS USING THIS SOFTWARE MAY ENCOUNTER PROBLEMS AND IT IS
  LIKELY THAT YOU MAY LOSE OR DESTROY DATA.  YOU MUST BACKUP YOUR SYSTEM
  PRIOR TO USING THIS SOFTWARE, AND SHOULD DO SO OFTEN DURING SUBSEQUENT
  USE. PLEASE DON'T COMPRESS ANYTHING THAT CANNOT BE EASILY REPLACED OR
  RESTORED. THIS VERSION OF PKZIP POSSIBLY MAY NOT BE COMPATIBLE WITH
  LATER VERSIONS OF THE SOFTWARE AND SHOULD NOT BE USED TO ARCHIVE FILES
  YOU PLAN TO EXCHANGE WITH OTHER PERSONS.


Disclaimer
----------

Although PKWARE will attempt to supply current and accurate information
relating to its file formats, algorithms, and the subject programs, the
possibility of error can not be eliminated. PKWARE therefore expressly
disclaims any warranty that the information contained in the associated
materials relating to the subject programs and/or the format of the
files created or accessed by the subject programs and/or the algorithms
used by the subject programs, or any other matter, is current, correct
or accurate as delivered.  Any risk of damage due to any possible
inaccurate information is assumed by the user of the information.
Furthermore, the information relating to the subject programs and/or the
file formats created or accessed by the subject programs and/or the
algorithms used by the subject programs is subject to change without
notice.

                                 ALPHA 1.93

Due to the extensive changes in PKZIP including the incorporation of our
new data compression technology, this ALPHA version is being made
available for a wide-spread test.  PLEASE be aware that this is NOT
final software, and must be treated as such.  It is EXTREMELY LIKELY
that files created with this version of PKZIP will NOT be compatible
with future/final releases of the product.  Therefore, do NOT use this
program to archive any data which cannot be replaced easily.  BBS SysOps
SHOULD NOT convert their archives to this release of PKZIP.  Although it
is true that significant space savings can be realized on all BBS's by
converting to the new compression, PLEASE wait until the final version
is available to ensure compatibility with your users and other BBS's.

This generation of PKZIP offers the following significant improvements
over previous releases:

1)  ALL NEW COMPRESSION ALGORITHM.  This new process allows PKZIP to
    compress data TIGHTER and FASTER.  In fact, the new FAST method gets
    more compression than the maximum compression in PKZIP 1.10, yet is
    almost as fast as Shrinking!

2)  MULTI-VOLUME ARCHIVES.  PKZIP can now create and extract ZIP files
    which cross more than one disk.  This is not functional in this
    Alpha 1.93 version.

3)  EMS SUPPORT.  When sufficient EMS is available PKZIP now requires
    only 85K of conventional memory to run.  Without EMS PKZIP requires
    183K.  PKUNZIP requires approximately 75K if EMS is present and
    approximately 81K without EMS.

=================
NEW PKZIP OPTIONS
=================
Brackets [] are used in command option descriptions only to indicate the
position of optional or required switches and are NEVER typed as part of
a command.

****
Compression Type
-e[s/n/x]

Specifying this parameter allows you to select the compression type you
desire.  (s) specifies the FAST compression algorithm, (x) specifies the
EXTRA compression algorithm.  (n) specifies the NORMAL (default)
compression type and is provided to override the configuration file in
future revisions.

Examples:

        pkzip -es test.zip *.doc
        pkzip -ex test2.zip *.gif

****
Date Specifier
-t[mmyydd]    (files on or AFTER this date)
-T[mmyydd]    (files BEFORE this date)

With this option, you can specify a date so that only files with a date
that is equal to or more recent/older will be included in the PKZIP
operation.  These options MAY be combined, but take care not to have
them overlap or you will exclude all files!

Examples:

        pkzip -ex -m -T010191 oldstuff *.wk1

        This example would compress all files matching the file
        specification *.wk1 and created before January 1st, 1991, and
        place them into the ZIP file called 'oldstuff.zip'.  This
        example is also using the EXTRA compression option and MOVING
        the files (deleting them after they are compressed).

        pkzip -t110191 catalog catalog.*

        This example would compress all files matching the file
        specification catalog.* (i.e. all files names catalog,
        regardless of extension) and created on or after November
        1st, 1991, and copy them into a ZIP files called 'catalog.zip'.

****
Create Multi-Volume Archives
-&

This feature is not functional in this ALPHA 1.93 version, but will be
in the final release of the product.

When this option is specified, and a ZIP file is being created on a
REMOVABLE DOS media device, PKZIP has permission to create a ZIP file
that is larger than that single media.  When a ZIP file reaches the
point where it would exceed the capacity of the storage device, the user
is prompted to insert another one.  In the case of standard floppy disks
(360K/720K/1.2M/1.44M) these disks may be formatted on-the-fly, that is,
if an un-formatted disk is inserted it will be formatted before PKZIP
continues to write the archive.

****
Open files in compatibility mode
-=

When this option is specified, PKZIP will open files for archiving in
compatibility mode, as opposed to 'sharing' mode.  On some systems this
will bypass any network sharing and allow PKZIP to read files opened by
other programs or applications.

****
Disable EMS usage
-+

If you experience strange behavior when testing PKZIP, try using this
option. When this option is on PKZIP will use only conventional memory.
Use of this switch may reveal problems or incompatibilities with your
EMS driver.  Please report these occurances.

===================
NEW PKUNZIP OPTIONS
===================
Brackets [] are used in command option descriptions only to indicate the
position of optional or required switches and are NEVER typed as part of
a command.

****
Command line options for PKUNZIP may now be combined!  This was possible
with previous versions of PKZIP but never before with PKUNZIP.  For
example in the past if you wanted to extract a ZIP file while restoring
directory paths AND overwrite any previously existing files by the same
name you needed to give the command with separate -d -o options, you may
now combine them as the single option -do.

Please note: As with PKZIP, you still MUST separate options which take
additional parameters themselves, such as -e (extract files in
designated order).  The -ed option is the extract files in order of file
date, thus if you had planned it to also restore directories it would
not be interpreted in that fashion.

****
Exclude Files
-xfilename
-x@exclude.lst

PKZIP allows you to create plain ASCII text files containing file names
that you wish to compress, or exclude from an operation.  Now with this
option you may specify a list of files to EXCLUDE from an unzip
operation, or a particular file.

Example:

        pkunzip testfile.zip -xmanual.txt

        This example would extract the files contained in the archive
        'testfile.zip' but not the file 'manual.txt'

        pkunzip -d a:project2.zip -x@nowant.lst

        This example would extract the files contained in the archive
        'project2.zip' (which incidentally is located on the a: drive
        and is having it's directory structure restored via the -d
        option and the a: being added to the file name).  The files
        contained in the list file 'nowant.lst' would NOT be extracted
        from this archive.

****
Disable EMS usage
-+

If you experience strange behavior when testing PKUNZIP, try this
option. When this option is on PKUNZIP will use only conventional
memory.  Use of this switch may reveal problems or incompatibilities
with your EMS driver.  Please report these occurances.

****
New Overwrite Option
(automatic)

Past versions of PKUNZIP, when encountering a file it was extracting
that already existed, would prompt you as to whether or not you wished
to overwrite the existing file.  This question could only be answered in
a yes or no manner.

Starting with this revision, PKUNZIP will now prompt you with:

File already exists overwrite (y/n/a/r)?

The four possible responses to this question are:

Y - Yes, overwrite the existing file with the version that is contained
    in the archive.

N - No, leave the existing file alone and skip to the next file.

A - All, overwrite the existing file, and do so for any others that are
    run across as well.  This is useful if you forget to specify -o when
    you give the original PKUNZIP command.

R - Rename it!  This will prompt you for a new name of the file and then
    extract the file in the archive to this new name.  This is very
    useful when extracting downloads from BBS systems, which frequently
    contain files such as 'readme.doc' or 'manual.doc' in many different
    files.

PKZIP 2.01

pc.js v3.00
Copyright © 2012-2026 Jeff Parsons <Jeff@pcjs.org>
Options: --disk=https://harddisks.pcjs.org/pcx86/10mb/MSDOS330-C400.json --diskette=https://discmaster.textfiles.com/file/30009/wbiz0250-0259/wbiz0250.tar/wbiz0250/PKZ201.ZIP
[Press CTRL-D to enter command mode]

A:\>DIR

 Volume in drive A has no label
 Directory of  A:\

OMBUDSMN ASP      595   3-15-92   2:01a
FILE_ID  DIZ      118   3-15-92   2:01a
BENCH    DOC     2449   3-15-92   2:01a
CRC      DOC     1888   3-15-92   2:01a
DEDICATE DOC      720   3-15-92   2:01a
MANUAL   DOC   132199   3-15-92   2:01a
ORDER    DOC     4654   3-15-92   2:01a
README   DOC      789   3-15-92   2:01a
WHATSNEW DOC     7885   3-15-92   2:01a
PKUNZIP  EXE    19793   3-15-92   2:01a
PKZIP    EXE    24869   3-15-92   2:01a
APPNOTE  TXT    32227   3-15-92   2:01a
WAREZ        <DIR>   
       13 File(s)     86016 bytes free

A:\>PKZIP

PKZIP (R)  FAST!  Create/Update Utility    Version 2.01   03-15-92    
Copr. 1989-1992 PKWARE Inc.  All Rights Reserved.  PKZIP/h for help
PKZIP Reg. U.S. Pat. and Tm. Off.                       

Usage: PKZIP [-b[path]] [options] zipfile [@list] [files...]
Options summary - consult the PKWARE documentation for additional information
  -x<filespec|@list> = eXclude filespec(s)            -z = add zipfile comment
  -d = delete files            -f = freshen files     -i = add changed files
  -l = display license info    -u = update files      -m[u,f] = move files
  -a = add files               -b = create temp zipfile on alternate drive
  -c = add/edit file comments  -C = add comments to new files only
  -k = keep same ZIP date      -o = set ZIP date to latest file
  -q = enable ANSI comments    -s<pwd> = Scramble files with password
  -r = recurse subdirs         -$[drive] = save volume label
  -<T|t>[mmddyy] = Compress files before|after specified date (default=today)
  -e[x,n,s] = maXimal compression/Normal compression/Speed(fast) compression
  -<p|P> = store pathnames | p=recursed into | P=specified & recursed into
  -<w|W><H,S> = | w=include | W=don't include | Hidden/System files
  -<j|J><H,S,R> = | j=mask | J=don't mask | Hidden/System/Readonly attributes
  -v[b,c,d,e,n,p,s,r,t] = view ZIP [Brief listing/show Comments/sort by -
    Date/Ext/Name/Percentage/Size/sort Reverse/Technical (long) listing]
zipfile = ZIP file name.  Default extension is .ZIP
file    = Names of files to compress. Wildcards *,? ok. Default is ALL files.
@list   = listfile containing names of files to add or view etc.
                         
If you find PKZIP fast, easy, and convenient to use, a registration of $33
would be encouraged. If you send $60 you will receive, when available,      
the next version of PKZIP, PKUNZIP, programs. Please state the version
of the software that you have, Please send check or money order to: PKWARE, Inc
7545 N.PORT Washington Rd.
Glendale, WI 53217
   
A:\>TYPE WHATSNEW.DOC
Copyright 1989-1992 PKWARE Inc.  All Rights Reserved.

Disclaimer
----------

Although PKWARE will attempt to supply current and accurate information
relating to its file formats, algorithms, and the subject programs, the
possibility of error can not be eliminated. PKWARE therefore expressly
disclaims any warranty that the information contained in the associated
materials relating to the subject programs and/or the format of the
files created or accessed by the subject programs and/or the algorithms
used by the subject programs, or any other matter, is current, correct
or accurate as delivered.  Any risk of damage due to any possible
inaccurate information is assumed by the user of the information.
Furthermore, the information relating to the subject programs and/or the
file formats created or accessed by the subject programs and/or the
algorithms used by the subject programs is subject to change without
notice.

                                 PKZIP V2.01

This generation of PKZIP offers the following significant improvements
over previous releases:

1)  ALL NEW COMPRESSION ALGORITHM.  This new process allows PKZIP to
    compress data TIGHTER and FASTER.  In fact, the new FAST method gets
    more compression than the maximum compression in PKZIP 1.10, yet is
    almost as fast as Shrinking!

2)  MULTI-VOLUME ARCHIVES.  PKZIP can now create and extract ZIP files
    which cross more than one disk.  This is only available in  the
    Registered version.

3)  EMS SUPPORT.  When sufficient EMS is available PKZIP now requires
    only 85K of conventional memory to run.  Without EMS PKZIP requires
    183K.  PKUNZIP requires approximately 75K if EMS is present and
    approximately 81K without EMS.

=================
NEW PKZIP OPTIONS
=================
Brackets [] are used in command option descriptions only to indicate the
position of optional or required switches and are NEVER typed as part of
a command.

****
Compression Type
-e[s/n/x]

Specifying this parameter allows you to select the compression type you
desire.  (s) specifies the FAST compression algorithm, (x) specifies the
EXTRA compression algorithm.  (n) specifies the NORMAL (default)
compression type and is provided to override the configuration file in
future revisions.

Examples:

        pkzip -es test.zip *.doc
        pkzip -ex test2.zip *.gif

****
Date Specifier
-t[mmyydd]    (files on or AFTER this date)
-T[mmyydd]    (files BEFORE this date)

With this option, you can specify a date so that only files with a date
that is equal to or more recent/older will be included in the PKZIP
operation.  These options MAY be combined, but take care not to have
them overlap or you will exclude all files!

Examples:

        pkzip -ex -m -T010191 oldstuff *.wk1

        This example would compress all files matching the file
        specification *.wk1 and created before January 1st, 1991, and
        place them into the ZIP file called 'oldstuff.zip'.  This
        example is also using the EXTRA compression option and MOVING
        the files (deleting them after they are compressed).

        pkzip -t110191 catalog catalog.*

        This example would compress all files matching the file
        specification catalog.* (i.e. all files names catalog,
        regardless of extension) and created on or after November
        1st, 1991, and copy them into a ZIP files called 'catalog.zip'.

****
Create Multi-Volume Archives
-&

This feature is only available in Registered versions!

When this option is specified, and a ZIP file is being created on a
REMOVABLE DOS media device, PKZIP has permission to create a ZIP file
that is larger than that single media.  When a ZIP file reaches the
point where it would exceed the capacity of the storage device, the user
is prompted to insert another one.  In the case of standard floppy disks
(360K/720K/1.2M/1.44M) these disks may be formatted on-the-fly, that is,
if an un-formatted disk is inserted it will be formatted before PKZIP
continues to write the archive.

****
Open files in compatibility mode
-=

When this option is specified, PKZIP will open files for archiving in
compatibility mode, as opposed to 'sharing' mode.  On some systems this
will bypass any network sharing and allow PKZIP to read files opened by
other programs or applications.

****
Disable EMS usage
-+

If you experience strange behavior when testing PKZIP, try using this
option. When this option is on PKZIP will use only conventional memory.
Use of this switch may reveal problems or incompatibilities with your
EMS driver.  Please report these occurances.

===================
NEW PKUNZIP OPTIONS
===================
Brackets [] are used in command option descriptions only to indicate the
position of optional or required switches and are NEVER typed as part of
a command.

****
Command line options for PKUNZIP may now be combined!  This was possible
with previous versions of PKZIP but never before with PKUNZIP.  For
example in the past if you wanted to extract a ZIP file while restoring
directory paths AND overwrite any previously existing files by the same
name you needed to give the command with separate -d -o options, you may
now combine them as the single option -do.

Please note: As with PKZIP, you still MUST separate options which take
additional parameters themselves, such as -e (extract files in
designated order).  The -ed option is the extract files in order of file
date, thus if you had planned it to also restore directories it would
not be interpreted in that fashion.

****
Exclude Files
-xfilename
-x@exclude.lst

PKZIP allows you to create plain ASCII text files containing file names
that you wish to compress, or exclude from an operation.  Now with this
option you may specify a list of files to EXCLUDE from an unzip
operation, or a particular file.

Example:

        pkunzip testfile.zip -xmanual.txt

        This example would extract the files contained in the archive
        'testfile.zip' but not the file 'manual.txt'

        pkunzip -d a:project2.zip -x@nowant.lst

        This example would extract the files contained in the archive
        'project2.zip' (which incidentally is located on the a: drive
        and is having it's directory structure restored via the -d
        option and the a: being added to the file name).  The files
        contained in the list file 'nowant.lst' would NOT be extracted
        from this archive.

****
Disable EMS usage
-+

If you experience strange behavior when testing PKUNZIP, try this
option. When this option is on PKUNZIP will use only conventional
memory.  Use of this switch may reveal problems or incompatibilities
with your EMS driver.  Please report these occurances.

****
New Overwrite Option
(automatic)

Past versions of PKUNZIP, when encountering a file it was extracting
that already existed, would prompt you as to whether or not you wished
to overwrite the existing file.  This question could only be answered in
a yes or no manner.

Starting with this revision, PKUNZIP will now prompt you with:

File already exists overwrite (y/n/a/r)?

The four possible responses to this question are:

Y - Yes, overwrite the existing file with the version that is contained
    in the archive.

N - No, leave the existing file alone and skip to the next file.

A - All, overwrite the existing file, and do so for any others that are
    run across as well.  This is useful if you forget to specify -o when
    you give the original PKUNZIP command.

R - Rename it!  This will prompt you for a new name of the file and then
    extract the file in the archive to this new name.  This is very
    useful when extracting downloads from BBS systems, which frequently
    contain files such as 'readme.doc' or 'manual.doc' in many different
    files.

PKZIP 2.04c

pc.js v3.00
Copyright © 2012-2026 Jeff Parsons <Jeff@pcjs.org>
Options: --disk=https://harddisks.pcjs.org/pcx86/10mb/MSDOS330-C400.json --diskette=https://discmaster.textfiles.com/file/18224/World_Of_Computer_Software-02-386-Vol-2of3.iso/w/wxpress2.zip/PKZ204C.EXE
[Press CTRL-D to enter command mode]

A:\>DIR

 Volume in drive A has no label
 Directory of  A:\

README   DOC      537  12-28-92   2:04a
SHAREWAR DOC      573  12-28-92   2:04a
WHATSNEW 204     2430  12-28-92   2:04a
LICENSE  DOC     3707  12-28-92   2:04a
ORDER    DOC     3456  12-28-92   2:04a
ADDENDUM DOC    13700  12-28-92   2:04a
MANUAL   DOC   191376  12-28-92   2:04a
AUTHVERI FRM     2299  12-28-92   2:04a
PKZIP    EXE    41462  12-28-92   2:04a
PKUNZIP  EXE    28806  12-28-92   2:04a
PKZIPFIX EXE     7672  12-28-92   2:04a
ZIP2EXE  EXE    27069  12-28-92   2:04a
PKUNZJR  COM     2750  12-28-92   2:04a
OMBUDSMN ASP      591  12-28-92   2:04a
       14 File(s)     28672 bytes free

A:\>PKZIP

PKZIP (R)   FAST!   Create/Update Utility   Version 2.04c   12-28-92
Copr. 1989-1992 PKWARE Inc.  All Rights Reserved.  Shareware Version
PKZIP Reg. U.S. Pat. and Tm. Off.   Patent No. 5,051,745


PKZIP /h[1] for basic help   PKZIP /h[2|3|4] for other help screens.


Usage:  PKZIP [options] zipfile [@list] [files...]


       Simple Usage:   PKZIP zipfile file(s)...
                         |      |      |
Program -----------------       |      |
                                |      |
New zipfile to create ----------       |
                                       |
File(s) you wish to compress ----------

The above usage is only a very basic example of PKZIP's capability.


Press 2 for more options (including spanning & formatting), press 3 for
advanced options, 4 for trouble shooting options, any other key to quit help.

If you use PKZIP on a regular basis you are strongly encouraged to register
it.  With a full registration of US $47.00 you will receive a comprehensive
printed manual, the latest version of PKZIP, PKUNZIP & PKSFX software, and
when available, the next version of the software.  See the documentation for
commercial and distribution licensing info.  Send check or money order to:
                PKWARE, Inc.
                9025 N. Deerwood Drive
                Brown Deer, WI 53223

A:\>TYPE WHATSNEW.204

Several new features have been added to PKZIP/PKUNZIP/PKSFX
version 2.04c.  Read the file ADDENDUM.DOC for a complete
description of these changes and enhancements.  Highlights
of PKZIP/PKUNZIP/PKSFX etc. version 2.04c include:

-Improved Compression

        PKZIP/PKUNZIP 2.04c implements a new compression algorithm
        called Deflating.  Deflating has varying levels of compression
        and speed available.  Both speed and compression are greatly
        improved over previous versions of PKZIP.

-Multi-Volume Archive Support/Formatting

        PKZIP/PKUNZIP 2.04c has the ability to "span" a .ZIP file across
        multiple diskettes if the final .ZIP file size would be greater
        than a single diskette.  PKZIP 2.04c also has the ability to
        format the destination diskettes on the fly.

-XMS/EMS Usage

        PKZIP/PKUNZIP 2.04c has the ability to use of EMS, UMB, and HMA
        memory, which will allow the ability to process more files or be
        able to run with less conventional memory.  PKZIP/PKUNZIP 2.04
        will run in as little as 85K of conventional memory if EMS or
        XMS memory is available.

-Novell Network Aware

        PKZIP 2.04c is Novell Netware "aware".  Updating or creating
        a .ZIP file on a network drive is much faster with the network
        support in PKZIP 2.04c.

-Auto CPU type detection.
        
        PKZIP/PKUNZIP 2.04c will detect what type of CPU it is being run
        on and will use instructions specifcally optimized for an 808x
        CPU, 80386 CPU, or 80486 CPU.

-DPMI support
        
        PKZIP/PKUNZIP 2.04c automatically detects if DPMI (DOS Protected
        Mode Interface) support is available and will execute code in
        32-bit protected mode for better speed.

-PKCFG program

        PKZIP 2.04c can be configured to best suit your needs through
        the use of the PKCFG program.  This is only available in the
        registered version of PKZIP.

-PKSFX Junior and PKUNZIP Junior

        These "Junior" programs use very little memory and are extremely
        small.  Although they are reduced in ability, their small size
        makes them very useful.

-Password Encryption

        Sensitive data files can be scrambled with password protection.
        The security of this feature has been significantly improved in
        PKZIP/PKUNZIP 2.04c.

-Authenticy Verification

        Users requiring authentication of archive files may request an
        Authenticy Verification code.  This allows users to create .ZIP
        files which PKUNZIP can detect tampering of.

PKZIP 2.04e

pc.js v3.00
Copyright © 2012-2026 Jeff Parsons <Jeff@pcjs.org>
Options: --disk=https://harddisks.pcjs.org/pcx86/10mb/MSDOS330-C400.json --diskette=https://discmaster.textfiles.com/file/4695/sound_sensations.iso/utils/zipfiles/pkz204e.exe
[Press CTRL-D to enter command mode]

A:\>DIR

 Volume in drive A has no label
 Directory of  A:\

README   DOC      536   1-25-93   2:04a
SHAREWAR DOC      573   1-25-93   2:04a
WHATSNEW 204     2430   1-25-93   2:04a
V204E    NEW     8837   1-25-93   2:04a
LICENSE  DOC     3707   1-25-93   2:04a
ORDER    DOC     3304   1-25-93   2:04a
ADDENDUM DOC    18782   1-25-93   2:04a
MANUAL   DOC   202252   1-25-93   2:04a
AUTHVERI FRM     2330   1-25-93   2:04a
PKZIP    EXE    42475   1-25-93   2:04a
PKUNZIP  EXE    29371   1-25-93   2:04a
PKZIPFIX EXE     7682   1-25-93   2:04a
ZIP2EXE  EXE    27326   1-25-93   2:04a
PKUNZJR  COM     2750   1-25-93   2:04a
OMBUDSMN ASP      591   1-25-93   2:04a
       15 File(s)      2048 bytes free

A:\>PKZIP

PKZIP (R)   FAST!   Create/Update Utility   Version 2.04e   01-25-93
Copr. 1989-1993 PKWARE Inc.  All Rights Reserved.  Shareware Version
PKZIP Reg. U.S. Pat. and Tm. Off.   Patent No. 5,051,745


PKZIP /h[1] for basic help   PKZIP /h[2|3|4] for other help screens.


Usage:  PKZIP [options] zipfile [@list] [files...]


       Simple Usage:   PKZIP zipfile file(s)...
                         |      |      |
Program -----------------       |      |
                                |      |
New zipfile to create ----------       |
                                       |
File(s) you wish to compress ----------

The above usage is only a very basic example of PKZIP's capability.


Press 2 for more options (including spanning & formatting), press 3 for
advanced options, 4 for trouble shooting options, any other key to quit help.

If you use PKZIP on a regular basis you are strongly encouraged to register
it.  With a full registration of US $47.00 you will receive a comprehensive
printed manual, the latest version of PKZIP, PKUNZIP & PKSFX software, and
when available, the next version of the software.  See the documentation for
commercial and distribution licensing info.  Send check or money order to:
                PKWARE, Inc.
                9025 N. Deerwood Drive
                Brown Deer, WI 53223

A:\>TYPE V204E.NEW

The following changes have been made in version 2.04e of
PKZIP/PKUNZIP from version 2.04c.

1) DPMI.

     The DPMI support in PKZIP/PKUNZIP has been changed to work
     around bugs and anomolies with the following DPMI drivers or
     environments.  PKWARE would like to thank Quarterdeck Office
     Systems and Qualitas, Inc. for their technical assistance
     regarding DPMI.

    a) PC-KWIK

      According to PC-KWIK corporation's document, 'PC-KWIK
      Technical Issues "Summer '92"':

        PC-KWIK is unable to recognize memory requests from programs
        using VCPI or DPMI protocols ... For programs [that use VCPI
        or DPMI] it is necessary to reduce the size of the cache and
        disable lending.

      PC-KWIK has a lending feature that allows memory to loaned
      from the cache memory to applications.  However, PC-KWIK is
      not aware of any memory allocated or used by DPMI, and will
      loan this memory as well, possibly causing corruption of the
      DPMI driver and usually resulting in a system crash or reboot.

      This problem seems to present in most versions of SUPERPCK,
      through version 5.01.

      In other words, when using PC-KWIK with any program that uses DPMI,
      including PKZIP and PKUNZIP, you should either make sure that you
      have enough memory in your computer so that lending will not occur,
      reduce the size of your cache, or disable PC-KWIK's lending.

      Therefore, PKZIP/PKUNZIP detect for the presence of PC-KWIK
      and default DPMI to DISABLE when PC-KWIK is installed.  This
      can be overidden by specifying -)+ on the PKZIP or PKUNZIP
      command line, or by placing DPMI=ENABLE in your PKZIP.CFG for
      PKZIP or setting the environment variable PKUNZIP=-)+ for PKUNZIP.

  b) QDPMI 1.00

      If a program tries to use DPMI and EMS memory with QDPMI 1.00,
      QDPMI would become unstable or crash.  PKZIP/PKUNZIP now
      check for the presence of QDPMI 1.00 and if PKZIP/PKUNZIP
      are using EMS memory, they do not attempt to use DPMI at all.

  c) QDPMI 1.01

      When a program switches to protected mode, QDPMI does not
      'synchronize' the EMS page frame.  The result is that programs
      can not correctly read or write any data in the EMS page frame
      while in proteced mode.  PKZIP/PKUNZIP now check for the presence
      of QDPMI 1.01 and will use slower real-mode code for any
      manipulation of data in the EMS page frame rather than faster
      protected mode code.

  d) OS/2 2.0 DOS BOX

      The OS/2 2.0 DOS box does not allow programs to allocate the
      'DPMI private data area' in an UMB.  Doing so causes a system
      violation error.  PKZIP/PKUNZIP now check to see if they are
      running in the OS/2 2.0 DOS box and will not allocate the DPMI
      private data area in an UMB.  (This is actually kind of a shame,
      as the OS/2 DOS box (unlike the Windows DOS box) provides UMB
      memory to DOS applications.  It should be able to allow programs
      to store the DPMI data area in these UMB's.)

  e) Windows 3.0 DOS BOX

      The DPMI support in the Windows 3.0 DOS box does not always
      seem to work correctly.  Therefore, PKZIP/PKUNZIP detect if
      they are running in the Windows 3.0 DOS box and will not support
      DPMI in this environment.

  f) Windows 3.1 DOS BOX

      The way PKZIP/PKUNZIP allocates the DPMI save/restore state
      buffer has been changed to be more compatible with Windows 3.1.

2)  The Norton AntiVirus program FALSELY reported that PKZIPFIX and
    PKUNZIP contained the Maltese Ameoba virus.  The software DID
    NOT contain this virus.  All files in this release have been
    modified so as to not trigger any FALSE virus reports by the
    Norton AntiVirus program.

3)  QEMM versions 5.1x would corrupt the high word of the 32-bit
    registers on an 80386 or 80486 CPU.  PKZIP/PKUNZIP check for
    this condition, and will not use 32-bit instructions if QEMM
    version 5.1x is present.

4)  Apparently some peer-to-peer networks such as Novell Netware Lite
    and others do not support canonical or fully specified filename.
    PKZIP now uses noncanonical filenames when specifying temporary
    filenames on a network drive to avoid this problem.

5)  PKZIP would erroneously report "E28 Destination is same as temp
    directory" when creating a new .zip file on drive A:.  This has
    been fixed.

6)  The keywords on/enable and off/disable are now synonymous when
    used in the PKZIP configuration file.

7)  Using EMS= options in the PKZIP configuration file would enable
    or disable both EMS and XMS usage.  The XMS= option had no effect.
    This has been corrected.

8)  The Quick format option in PKZIP would zero out the existing FAT
    on the disk (by design).  However, if the disk had any bad
    sectors on it (in which case, it isn't a good idea to use that
    disk as a backup disk anyway...) they would now be marked as
    good.  By popular demand, PKZIP now reads the existing FAT and
    leaves any bad sectors marked as bad.  This however, makes the
    'Quick' format function about twice as slow as it was (although
    still much faster than an unconditional format).  In most cases
    however, unless there are several subdirectories on the diskette,
    the -&w (wipe) option is faster than the -&f (format) option when
    backing up to pre-formatted diskettes.

9)  Under some cirumstances, PKZIP could possibly store the last
    file in a multi-disk backup set incorrectly.  This has been
    corrected.

10) The volume label option in PKZIP would not work.  This has been
    fixed.

11) PKZIP/PKUNZIP now searches for a PKNOFASTCHAR variable in the
    DOS environment.  If this variable is present, PKZIP/PKUNZIP
    will use the slower DOS 1.x/2.x character output functions
    rather than the 'DOS Fast Character Output' function.  This is
    provided for compatability with some TSR's, BBS Doors and mail
    readers etc., that redirect or capture the output of programs and
    do not support the DOS Fast Character Output function.

12) PKZIP will now accept either MAXIMUM or MAXIMAL in the
    configuration file.

13) Some people have requested that the -& backup option support the
    DOS verify function.  Specifying -&v on the PKZIP command line
    or BACKUP=VERIFY in the PKZIP.CFG file will turn on the DOS
    verify flag when writing to the backup disk(s).  This makes
    PKZIP run slower, but ensures better integrity of each diskette.

14) Using the -m option with -rp in PKZIP will delete any empty
    subdirectories that have been saved in the .ZIP file after all
    the files have been moved into the .ZIP file.  Some people have
    requested a way to have PKZIP leave these empty subdirectories
    behind.  This can be accomplished by using -m- on the PKZIP
    command line.

15) It appears that some versions of NoGate's PAK program would
    place incorrect information in the .ZIP file directories that it
    created.  Specifically, the disk number information for where
    files, the central directory, and the central end directory
    started is inconsistent, causing PKUNZIP to think it was
    extracting a multi-disk .ZIP file when it really wasn't.
    PKUNZIP now checks for this condition, and ignores this
    erroneous information.

16) PKZIP now ignores any ZIPDATE= or -o or -k options when creating
    multi-disk .ZIP files, rather than displaying the help screens.

17) On some 80386 machines running PKZIP could leave allocated UMB's
    behind.  This has been corrected.

18) In some circumstances, running PKZIP with EMS memory and very low
    free conventional memory could cause corruption of the .ZIP file.
    This has been corrected.

19) When PKZIP prompts for an encryption password, it will now ask the
    user to enter the password twice for verification.

20) PKZIP/PKUNZIP would not work under DOS 2.x.  This is because
    DOS 2.x crashes on many int 2Fh installation check calls for
    EMS/XMS drivers etc.  These calls work properly under DOS 3.0
    or above.  Therefore, PKZIP/PKUNZIP detect for the presence
    of DOS 2.x, and will not support any of the advanced features
    including 32-bit instructions, EMS memory, XMS memory, DPMI
    support and Netware usage.

21) PKSFX could in some instances erroneously report failed AV's or
    garble any AVEXTRA text present.  This has been fixed.

22) Using PKZIP with the -o option or ZIPDATE=LATEST in the configuration
    file would set the date of the .ZIP file to the latest dated file
    or directory.  Directory dates are now ignored in this version.

PKZIP 2.04g

pc.js v3.00
Copyright © 2012-2026 Jeff Parsons <Jeff@pcjs.org>
Options: --disk=https://harddisks.pcjs.org/pcx86/10mb/MSDOS330-C400.json --diskette=https://discmaster.textfiles.com/file/6140/BSTETRS2.bin/utils/pkware/pkz204g/pkz204g.exe
[Press CTRL-D to enter command mode]

A:\>DIR

 Volume in drive A has no label
 Directory of  A:\

README   DOC      741   2-01-93   2:04a
SHAREWAR DOC      573   2-01-93   2:04a
WHATSNEW 204     2430   2-01-93   2:04a
V204G    NEW    10704   2-01-93   2:04a
HINTS    TXT    14109   2-01-93   2:04a
LICENSE  DOC     3707   2-01-93   2:04a
ORDER    DOC     3304   2-01-93   2:04a
ADDENDUM DOC    19361   2-01-93   2:04a
MANUAL   DOC   202252   2-01-93   2:04a
AUTHVERI FRM     2330   2-01-93   2:04a
PKZIP    EXE    42166   2-01-93   2:04a
PKUNZIP  EXE    29378   2-01-93   2:04a
PKZIPFIX EXE     7687   2-01-93   2:04a
ZIP2EXE  EXE    27319   2-01-93   2:04a
PKUNZJR  COM     2750   2-01-93   2:04a
OMBUDSMN ASP      591   2-01-93   2:04a
       16 File(s)    839680 bytes free

A:\>PKZIP

PKZIP (R)   FAST!   Create/Update Utility   Version 2.04g   02-01-93
Copr. 1989-1993 PKWARE Inc.  All Rights Reserved.  Shareware Version
PKZIP Reg. U.S. Pat. and Tm. Off.   Patent No. 5,051,745


PKZIP /h[1] for basic help   PKZIP /h[2|3|4] for other help screens.


Usage:  PKZIP [options] zipfile [@list] [files...]


       Simple Usage:   PKZIP zipfile file(s)...
                         |      |      |
Program -----------------       |      |
                                |      |
New zipfile to create ----------       |
                                       |
File(s) you wish to compress ----------

The above usage is only a very basic example of PKZIP's capability.


Press 2 for more options (including spanning & formatting), press 3 for
advanced options, 4 for trouble shooting options, any other key to quit help.

If you use PKZIP on a regular basis you are strongly encouraged to register
it.  With a full registration of US $47.00 you will receive a comprehensive
printed manual, the latest version of PKZIP, PKUNZIP & PKSFX software, and
when available, the next version of the software.  See the documentation for
commercial and distribution licensing info.  Send check or money order to:
                PKWARE, Inc.
                9025 N. Deerwood Drive
                Brown Deer, WI 53223

A:\>TYPE V204G.NEW

Please note that the only program that has functionally changed
from version 2.04e to 2.04g is PKZIP.EXE, PKUNZIP.EXE and PKCFG.EXE.
The other programs in this release have been changed to read version
2.04g for consistency.  However, no functional changes have been made
to them.


The following changes have been made in version 2.04g of PKZIP.EXE
from version 2.04e.

1)  PKZIP's Quick format in an over-zealous effort to leave bad
    sectors marked as bad, could in some instances leave unallocated
    sectors (orphaned clusters) on the diskette.  This has been fixed.


The following changes have been made in version 2.04g of PKZIP.EXE
from version 2.04c/2.04e.

1)  Using the BACKUP= option in the PKZIP.CFG file would automatically
    turn on the SPAN option and cause PKZIP to generate a E27 or E28
    error, or display the help screen when creating a .ZIP file
    on non-removable media.  This has been corrected.

2)  When Norton Utilities creates a volume label on a diskette, it 
    stores trailing nulls rather than trailing spaces after the volume 
    name, as DOS does (and expects).  A volume label created by NU can 
    not be changed by even the LABEL command in DOS.  PKZIP uses the 
    volume label when creating multi-disk .ZIP files, and could not 
    change any volume label created by NU.  PKZIP has been modified to 
    be able to deal with and change volume labels created by NU.  
    PKUNZIP -$ was also unable to restore volume labels over NU created 
    labels.  PKUNZIP has been modified to deal with NU volume labels as 
    well.


The following changes have been made in version 2.04e of
PKZIP/PKUNZIP from version 2.04c.

1) DPMI.

     The DPMI support in PKZIP/PKUNZIP has been changed to work
     around bugs and anomolies with the following DPMI drivers or
     environments.  PKWARE would like to thank Quarterdeck Office
     Systems and Qualitas, Inc. for their technical assistance
     regarding DPMI.

    a) PC-KWIK

      According to PC-KWIK corporation's document, 'PC-KWIK
      Technical Issues "Summer '92"':

        PC-KWIK is unable to recognize memory requests from programs
        using VCPI or DPMI protocols ... For programs [that use VCPI
        or DPMI] it is necessary to reduce the size of the cache and
        disable lending.

      PC-KWIK has a lending feature that allows memory to be loaned
      from the cache memory to applications.  However, PC-KWIK is
      not aware of any memory allocated or used by DPMI, and will
      loan this memory as well, possibly causing corruption of the
      DPMI driver and usually resulting in a system crash or reboot.

      PKWARE has tested several versions of SUPERPCK, through version
      5.01 and running PKZIP (as well as several commercial programs
      that use DPMI) consistently causes a system reboot or some kind
      of protected mode error such as a page fault.  PC-KWIK Corporation
      is aware of this problem, and is trying to correct it.

      In other words, when using PC-KWIK with any program that uses DPMI,
      including PKZIP and PKUNZIP, you should either make sure that you
      have enough memory in your computer so that lending will not occur,
      reduce the size of your cache, or disable PC-KWIK's lending.

      Therefore, PKZIP/PKUNZIP detect for the presence of PC-KWIK
      and default DPMI to DISABLE when PC-KWIK is installed.  This
      can be overidden by specifying -)+ on the PKZIP or PKUNZIP
      command line, or by placing DPMI=ENABLE in your PKZIP.CFG for
      PKZIP or setting the environment variable PKUNZIP=-)+ for PKUNZIP.

  b) QDPMI 1.00

      If a program tries to use DPMI and EMS memory with QDPMI 1.00,
      QDPMI would become unstable or crash.  PKZIP/PKUNZIP now
      check for the presence of QDPMI 1.00 and if PKZIP/PKUNZIP
      are using EMS memory, they do not attempt to use DPMI at all.

  c) QDPMI 1.01

      When a program switches to protected mode, QDPMI does not
      'synchronize' the EMS page frame.  The result is that programs
      can not correctly read or write any data in the EMS page frame
      while in proteced mode.  PKZIP/PKUNZIP now check for the presence
      of QDPMI 1.01 and will use slower real-mode code for any
      manipulation of data in the EMS page frame rather than faster
      protected mode code.

  d) OS/2 2.0 DOS BOX

      The OS/2 2.0 DOS box does not allow programs to allocate the
      'DPMI private data area' in an UMB.  Doing so causes a system
      violation error.  PKZIP/PKUNZIP now check to see if they are
      running in the OS/2 2.0 DOS box and will not allocate the DPMI
      private data area in an UMB.  (This is actually kind of a shame,
      as the OS/2 DOS box (unlike the Windows DOS box) provides UMB
      memory to DOS applications.  It should be able to allow programs
      to store the DPMI data area in these UMB's.)

  e) Windows 3.0 DOS BOX

      The DPMI support in the Windows 3.0 DOS box does not always
      seem to work correctly.  Therefore, PKZIP/PKUNZIP detect if
      they are running in the Windows 3.0 DOS box and will not support
      DPMI in this environment.

  f) Windows 3.1 DOS BOX

      The way PKZIP/PKUNZIP allocates the DPMI save/restore state
      buffer has been changed to be more compatible with Windows 3.1.

2)  The Norton AntiVirus program FALSELY reported that PKZIPFIX and
    PKUNZIP contained the Maltese Ameoba virus.  The software DID
    NOT contain this virus.  All files in this release have been
    modified so as to not trigger any FALSE virus reports by the
    Norton AntiVirus program.

3)  QEMM versions 5.1x would corrupt the high word of the 32-bit
    registers on an 80386 or 80486 CPU.  PKZIP/PKUNZIP check for
    this condition, and will not use 32-bit instructions if QEMM
    version 5.1x is present.

4)  Apparently some peer-to-peer networks such as Novell Netware Lite
    and others do not support canonical or fully specified filename.
    PKZIP now uses noncanonical filenames when specifying temporary
    filenames on a network drive to avoid this problem.

5)  PKZIP would erroneously report "E28 Destination is same as temp
    directory" when creating a new .zip file on drive A:.  This has
    been fixed.

6)  The keywords on/enable and off/disable are now synonymous when
    used in the PKZIP configuration file.

7)  Using EMS= options in the PKZIP configuration file would enable
    or disable both EMS and XMS usage.  The XMS= option had no effect.
    This has been corrected.

8)  The Quick format option in PKZIP would zero out the existing FAT
    on the disk (by design).  However, if the disk had any bad
    sectors on it (in which case, it isn't a good idea to use that
    disk as a backup disk anyway...) they would now be marked as
    good.  By popular demand, PKZIP now reads the existing FAT and
    leaves any bad sectors marked as bad.  This however, makes the
    'Quick' format function about twice as slow as it was (although
    still much faster than an unconditional format).  In most cases
    however, unless there are several subdirectories on the diskette,
    the -&w (wipe) option is faster than the -&f (format) option when
    backing up to pre-formatted diskettes.

9)  Under some cirumstances, PKZIP could possibly store the last
    file in a multi-disk backup set incorrectly.  This has been
    corrected.

10) The volume label option in PKZIP would not work.  This has been
    fixed.

11) PKZIP/PKUNZIP now searches for a PKNOFASTCHAR variable in the
    DOS environment.  If this variable is present, PKZIP/PKUNZIP
    will use the slower DOS 1.x/2.x character output functions
    rather than the 'DOS Fast Character Output' function.  This is
    provided for compatability with some TSR's, BBS Doors and mail
    readers etc., that redirect or capture the output of programs and
    do not support the DOS Fast Character Output function.

12) PKZIP will now accept either MAXIMUM or MAXIMAL in the
    configuration file.

13) Some people have requested that the -& backup option support the
    DOS verify function.  Specifying -&v on the PKZIP command line
    or BACKUP=VERIFY in the PKZIP.CFG file will turn on the DOS
    verify flag when writing to the backup disk(s).  This makes
    PKZIP run slower, but ensures better integrity of each diskette.

14) Using the -m option with -rp in PKZIP will delete any empty
    subdirectories that have been saved in the .ZIP file after all
    the files have been moved into the .ZIP file.  Some people have
    requested a way to have PKZIP leave these empty subdirectories
    behind.  This can be accomplished by using -m- on the PKZIP
    command line.

15) It appears that some versions of NoGate's PAK program would
    place incorrect information in the .ZIP file directories that it
    created.  Specifically, the disk number information for where
    files, the central directory, and the central end directory
    started is inconsistent, causing PKUNZIP to think it was
    extracting a multi-disk .ZIP file when it really wasn't.
    PKUNZIP now checks for this condition, and ignores this
    erroneous information.

16) PKZIP now ignores any ZIPDATE= or -o or -k options when creating
    multi-disk .ZIP files, rather than displaying the help screens.

17) On some 80386 machines running PKZIP could leave allocated UMB's
    behind.  This has been corrected.

18) In some circumstances, running PKZIP with EMS memory and very low
    free conventional memory could cause corruption of the .ZIP file.
    This has been corrected.

19) When PKZIP prompts for an encryption password, it will now ask the
    user to enter the password twice for verification.

20) PKZIP/PKUNZIP would not work under DOS 2.x.  This is because
    DOS 2.x crashes on many int 2Fh installation check calls for
    EMS/XMS drivers etc.  These calls work properly under DOS 3.0
    or above.  Therefore, PKZIP/PKUNZIP detect for the presence
    of DOS 2.x, and will not support any of the advanced features
    including 32-bit instructions, EMS memory, XMS memory, DPMI
    support and Netware usage.

21) PKSFX could in some instances erroneously report failed AV's or
    garble any AVEXTRA text present.  This has been fixed.

22) Using PKZIP with the -o option or ZIPDATE=LATEST in the configuration
    file would set the date of the .ZIP file to the latest dated file
    or directory.  Directory dates are now ignored in this version.

Thirty Years Ago: MS-DOS 6.00, DoubleSpace, and MultiConfig

Wed, 04 Oct 2023 08:00:00 +0000

Over 30 years ago, in March 1993, Microsoft released MS-DOS 6.00, the next major release of MS-DOS after 5.00 shipped in June 1991.

In addition to several new full-screen utilities, like DEFRAG to defragment your hard disk (licensed from Symantec), MSBACKUP to efficiently backup your hard disk (also licensed from Symantec), and MSAV to check for viruses (licensed from Central Point Software), there were a number of new command-line programs, such as CHOICE, DELTREE, MOVE, MSCDEX, and SMARTDRV.

But the biggest addition to MS-DOS 6.00 was a new feature called DoubleSpace (dubbed “MagicDrive” internally) that automatically compressed everything on your hard disk, providing up to “double” the amount of effective disk space – or more, or less, depending on how compressible your files were overall.

DoubleSpace was a significant feature that required changes across the entire system. Most of the action, however, took place inside a new device driver, DBLSPACE.BIN, that stored all your data in a Compressed Volume File (CVF) generally named DBLSPACE.000. In fact, if you booted an older version of MS-DOS (like 5.00), you wouldn’t see much more than that:

A>DIR C: /A

 Volume in drive C is HOST_FOR_C
 Volume Serial Number is 5739-B1B5
 Directory of C:\

IO       SYS     40470 03-10-93   6:00a
MSDOS    SYS     38138 03-10-93   6:00a
DBLSPACE BIN     51214 03-10-93   6:00a
DBLSPACE INI        91 10-03-23  12:26p
DBLSPACE 000 131474432 10-03-23  12:26p
        5 file(s)  131604345 bytes
                     2605056 bytes free

When MS-DOS 6.00 starts up, it reads DBLSPACE.INI, which usually looks something like this:

MaxRemovableDrives=2
FirstDrive=D
LastDrive=H
MaxFileFragments=115
ActivateDrive=H,C0

and tells the operating system to mount the real drive C: as drive H: instead, and to mount the CVF as drive C:

C:\>DIR /C

 Volume in drive C is MS-DOS_6
 Volume Serial Number is 101B-323E
 Directory of C:\

DOS          <DIR>     09-25-23  10:13p
COMMAND  COM     52925 03-10-93   6:00a   1.4 to 1.0
WINA20   386      9349 03-10-93   6:00a   5.3 to 1.0
AUTOEXEC BAT        75 09-26-23   8:55a  16.0 to 1.0
CONFIG   SYS       109 09-26-23   8:55a  16.0 to 1.0
                  2.0 to 1.0 average compression ratio
        5 file(s)      62458 bytes
                   253927424 bytes free

So our original hard disk, a 128Mb drive, now appears to be almost twice as large – thanks to DoubleSpace.

Aside from the new DBLSPACE.BIN driver, the other main piece of DoubleSpace functionality resided in DBLSPACE.EXE, which operated as both a setup and a maintenance program. It provided a friendly full-screen interface, making it easy to create additional CVFs, as well as resize, defragment, reformat, unmount, remount, and more.

Feel free to tinker with MS-DOS 6.00 on the website:

Legal Woes

Microsoft bootstrapped its compression efforts by licensing code from Vertisoft, makers of DoubleDisk, a disk compression product first released in 1989. Starting with Verisoft’s code, Microsoft created DBLSPACE.BIN, along with operating system changes that allowed it to be loaded before CONFIG.SYS was processed – so that CONFIG.SYS and any system files loaded from that point forward could be inside the compressed volume instead of outside it.

Vertisoft was not directly involved with any of that work, but they did help produce other pieces of functionality, such as code to convert Stacker and SuperStor compressed disks to DoubleSpace – although apparently Stacker conversion was pulled at the last minute, in February 1993, just as MS-DOS 6.00 was being finalized.

Or rather, February 1993 would have been “last minute”, until the lawsuit filed by Stac in January 1993 forced Microsoft to re-evaluate. Stac claimed that the DoubleSpace infringed two of Stac’s patents: 5,016,009 and 4,701,745.

For me, life quickly changed on February 13, 1993, when I received this email:

From: Paul Maritz
Sent: Saturday, February 13, 1993 12:06 PM
To: Jeff Parsons; Mark Zbikowski
Cc: Ben Slivka; Brad Chase; Brad Silverberg; Jim Allchin; John Mason;
Nathan Myhrvold; Rick Rashid
Subject: special duty

You are both amongst the best x86 assembly language coders that we have at MS.
We are thus asking you to help out with a very serious problem that we face - namely
the STAC / DOS6 lawsuit.

Our lawyers have recommended that we have a backup compression mechanism for DOS6
ready to go as soon as possible. The initial work on this has been done under Rick
Rashid in Nathanm's area. They have a C language implementation of a technique that
we believe is safe (covered under patents that we have rights to). The challenge
is to get this technique into the tightest possible x86 assembly code, as soon as
possible. This is where we are asking you to help. Jimall and Bradsi are aware that
you will be "stolen" for some weeks.

Could you both meet with Rick Rashid as early as possible on Monday to get this
effort under way as soon as is possible. Thanks.

The next several weeks were probably some of the most stressful that I’d experienced at Microsoft. Looking back, it’s amazing to me that with all the critical-path code that was being rewritten at that late date, MS-DOS 6.00 still shipped the following month, in March 1993.

I don’t recall all the details of the alleged patent infringement, and I’m not sure I ever knew all the details, because frankly, it wasn’t necessary for me to know the details. A number of other people had already been working on the problem and had come up with several solutions, and it simply fell to me and MarkZ to implement them in x86 assembly – preferably very fast, bug-free assembly, of course.

As far as I can tell now, Stac patent 5,016,009 was the crux of the problem. It combined LZ77 compression with hashing, and while LZ77 compression was fine, and hashing was fine, apparently the combination of the two became a patentable innovation.

So we were initially tasked with writing a compressor based on Miller-Wegman, an algorithm that was either not patented or that Microsoft owned or licensed. When that turned out to be too slow, we instead built a compressor (internally known as XCFR or the “Rashid Search Algorithm”) that avoided hashing by using a 256x8 look-up table along with a 256-entry LRU table, and also incorporated a new Microsoft Realtime Compression Format (MRCF) for outputting the raw bytes and offset-length pairs. That, of course, meant that the decompressor had to be rewritten as well.

With hindsight, it’s probably safe to say that Microsoft should not have shipped MS-DOS 6.00 quite so quickly after that rewrite, because unfortunately, our code (well, in the case below, my code) was not, um, bug-free:

From: Chuck Strouss
To: SYS Astro Team Development Group; Peter Stewart; Jeff Parsons
Subject: Bug in DBLSPACE decompress
Date: Monday, June 14, 1993 3:40PM

In RDCOMP.ASM, near the first JC instruction, there is a bug when a block ends
at 10000h and the last several bytes are in a repeat string.  It was reported by
Temporal Acuity Products.

to which I replied:

From: Jeff Parsons
Sent: Monday, June 14, 1993 4:49 PM
To: Chuck Strouss; Ben Slivka; Jim Mathews; Peter Stewart
Subject: RE: Bug in DBLSPACE decompress

well... shit!

That bug was only in the 80386 code path, so it could be avoided by adding an undocumented “ENABLE386=0” to DBLSPACE.INI, but that wasn’t much consolation. And it was one of at least a half-dozen or so DoubleSpace bugs that Microsoft was aware by June of 1993. Other bugs included:

A particular series of reads, writes, and undeletes may cause an undelete to fail (FAT is marked USED, but MDFAT is left marked FREE; note that MDFAT refers to the “MagicDrive” FAT internal to the CVF)
A particular series of operations followed by undelete may cause a cross link (not taking into account data that may be in buffers)
Read into video memory in planar VGA modes results in garbage display (decompression depends on being able to read previously decompressed data, but VGA memory in these video modes does not read back what was written to it)
If a disk error occurs while updating a cluster, a cross link may be created (error would be on writing to a part of the sector heap that we had not used previously)
When Metro Software’s LaserTwin 5.0 TSR is loaded, it intercepts write operations and breaks them up into smaller writes; however, sometimes those smaller writes can end up being ZERO bytes long, which DOS correctly treats as a truncate operation. If that happens when the system is writing to the DoubleSpace CVF, the compressed volume will be truncated (not really a DoubleSpace bug, but a bug with severe consequences)

I don’t know if the video memory issue was ever fixed. Wikipedia’s article on DriveSpace (which was the new name for DoubleSpace as of MS-DOS 6.22) alludes to the problem:

A few computer programs, particularly games, were incompatible with DoubleSpace because they effectively bypassed the DoubleSpace driver.

But I’m not aware of any problems that involved “bypassing” the driver. Any game-related problems were almost certainly due to DoubleSpace decompressing data directly into video memory when the video card’s read and write modes differed.

Introducing MultiConfig

On a happier, or at least less contentious note, MS-DOS 6.00 also introduced a feature known as MultiConfig, which I have some fondness for, because it was something I personally championed and implemented. And – good news – I don’t think it had any serious bugs.

I don’t recall precisely where the idea came from. I think it started as something that I and Naveen Jain, a Program Manager on the team, discussed in early 1992. He created a preliminary spec in February 1992, and then I implemented the feature in March 1992 and updated the spec to match what I had implemented.

The code was originally added to Jaguar, which was planned to be the next major update to MS-DOS after 5.00. But at some point, Astro – originally intended as a smaller interim MS-DOS update – grew to the point where it was clearly going to be the next major update, thanks in large part to the addition of DoubleSpace disk compression.

When it was clear that Astro would become MS-DOS 6.00, I think management went looking for other low-hanging fruit, such as any new Jaguar features that could be incorporated into Astro relatively easily with minimal risk. MultiConfig fit the bill.

However, it wasn’t a slam dunk. I had to push for it, because there were a few risk-averse people in management that felt the risk/reward ratio was too high. They claimed that most users would not use this feature (which was true), but that point also worked in my favor: most of the new code would not be executed until and unless someone actually added one or more of the new commands to their CONFIG.SYS. So any risks largely affected only “power users”.

What is MultiConfig?

MultiConfig was a collection of features added to the processing of CONFIG.SYS, to make it easier to start your PC in a particular way without having to boot from a special floppy or edit/copy a new CONFIG.SYS each time. It added some new commands to CONFIG.SYS:

INCLUDE
MENUCOLOR
MENUDEFAULT
MENUITEM
NUMLOCK
SET
SUBMENU

and it included some new ways to interact with CONFIG.SYS. The message “Starting MS-DOS…” was added as an indirect means of alerting you that you now had two seconds to press one of several new start-up keys:

F5: Bypass CONFIG.SYS and AUTOEXEC.BAT
F8: Interactively step through CONFIG.SYS

You could also tap a Shift key – that was equivalent to pressing F5. Apparently there was an Astro “press tour” in August 1992, and someone in that tour suggested adding the Shift key, so we did. They claimed that holding the Shift key while starting Windows also bypassed certain files and/or functions, but I don’t recall to what extent that was true.

Additionally, if you didn’t want anyone using your machine to bypass or alter CONFIG.SYS, you could add these lines to the file:

SWITCHES=/N: disable all start-up keys
SWITCHES=/F: eliminate the two-second pause

/N also implied /F, since if start-up keys were disabled, there was no need to wait two seconds.

Note that SWITCHES was not a new command; other older “switches” included:

/K: Forces an enhanced keyboard to behave like a conventional keyboard (DOS 4.0+)
/T: Indicates the BIOS time rollover byte is a flag instead of a counter (DOS 5.0+)
/W: Specifies that the WINA20.386 file has been moved to a directory other than the root directory (DOS 5.0+)

Finally, while we’re on the subject of the keyboard-related features, I should add that NUMLOCK wasn’t really a MultiConfig feature; it was just something I thought would be handy. Recall that early PCs had no BIOS setup screens, and MS-DOS was still an operating system designed to run on any PC, including the original IBM PC. So this CONFIG.SYS command:

NUMLOCK=[ON|OFF]

could be used to set your keyboard’s initial Num-Lock state. A case could be made for this being a legitimate MultiConfig feature though, since you could select menu items with arrow keys or by pressing the number of a menu item. So if you wanted to use your numeric keypad, then you would want to ensure that Num-Lock matched your preferred selection method.

With Great Power Comes… Menus

The real power of MultiConfig was the ability to create user-friendly boot menus and let you organize sets of CONFIG.SYS commands into either named or [common] blocks. Blocks began with a bracketed block name (eg, [menu], [common], [doslow]) and ended at the next bracketed block name (or end of file).

Here’s a simple example:

[menu]
menuitem=doslow,Load DOS in LOW memory
menuitem=doshigh,Load DOS in HIGH memory
menudefault=doslow,15
menucolor=15,1

[common]
device=c:\dos\himem.sys

[doslow]
dos=low

[doshigh]
dos=high

[common]
device=c:\dos\setver.exe
files=30

And the screen that would appear when booting:

Each menuitem in the [menu] block describes a menu item; the first argument is a block name (eg, doslow, doshigh), and the second argument is a description. Other [menu] block keywords included menudefault, which specifies the default menu item (and optional timeout value in seconds), and menucolor, which selects foreground and background colors for the menu.

In the above example, no matter which menu item you selected, HIMEM.SYS would always be loaded first, because it was in a [common] block that appeared before the other blocks. Then all commands in the selected block ([doslow] or [doshigh]) would be processed next, then all the commands in the next [common] block – and so on.

Another feature was “forced prompting”. If you included a ? after the DEVICE keyword, you would receive an unconditional prompt for that particular driver. For example:

device?=c:\dos\setver.exe

would always generate the following prompt:

DEVICE=C:\DOS\SETVER.EXE [Y,N]?

And that feature wasn’t limited to device drivers. The following line:

dos?=high

would also generate a prompt:

DOS=HIGH [Y,N]?

Below is a more complex example, extracted from an email I wrote back on July 1, 1992 (at 2:34am apparently).

This example illustrates how you could use submenu (as opposed to menuitem) to define menu items that referred to other menu blocks, in order to create multi-level menus. Originally, the keyword for that feature was simply menu, but the Astro team (specifically, Betsy Tinney, who helped refine the MultiConfig UI for Astro) suggested a keyword that was clearer.

It also shows how you could include named blocks from other blocks. For example, a number of the blocks, like [dosumb], include another block, [dos], that contains commands common to the other blocks. Every block could duplicate those commands itself, but factoring out common sets of commands made for a more maintainable CONFIG.SYS. Blocks named [common] were always processed in the order they appeared, whereas blocks with any other name would be processed whenever (and only whenever) they were explicitly included.

Finally, this example also uses the SET command, which defines environment variables to be passed to COMMAND.COM. In addition, a special CONFIG environment variable is automatically set to the name of the block from the final selected menuitem (eg, dosumb). This was useful for batch files like AUTOEXEC.BAT, if they needed to customize their actions according to the selected CONFIG.SYS configuration.

[menu]
numlock=off
menucolor=15,1
menudefault=lanmenu,15
submenu=dosmenu,DOS configurations
submenu=lanmenu,LanMan configurations

[dosmenu]
menudefault=dosumb,15
menuitem=dosumb,     DOS 7.00 only
menuitem=dosems,     DOS 7.00 w/EMS
menuitem=dosansi,    DOS 7.00 w/ANSI
menuitem=dos386max,  DOS 7.00 w/386Max
menuitem=dosdbg,     DOS 7.00 w/Soft-ICE
menuitem=cougar,     DOS 7.00 w/Cougar

[lanmenu]
menudefault=winball,15
menuitem=lanman20,   DOS 7.00 w/Lanman 2.0
menuitem=lanman21,   DOS 7.00 w/Lanman 2.1 w/XNS
menuitem=lanman21nb, DOS 7.00 w/Lanman 2.1 w/XNS+NetBeui
;menuitem=lanman21xm,DOS 7.00 w/Lanman 2.1 w/XNS Mono
menuitem=lanman21dbg,DOS 7.00 w/Lanman 2.1 w/Soft-ICE
menuitem=winball,    DOS 7.00 w/Winball

[common]
set tmp=c:\tmp
set linktmp=c:\tmp
set temp=c:\win31\temp
set dircmd=/l/o
set home=d:\tools\bound
set init=d:\tools\bound
set alias=jeffpar
set logname=jeffpar
set mailname=jeffpar
set basspec=d:\tools\dos
set helpfiles=d:\tools\help;c:\src\cougar\dev\tools\help
set country=usa-ms
set proj=c:\src\cougar\dos\dos86
set lib=d:\tools\windev\lib
set include=d:\tools\windev\include;d:\src\myinc
set path=d:\tools\dos;d:\tools\bound;d:\tools\windev;c:\lanman\netprog;c:\win31;c:\dos
set prompt=$p$g

[dos]
break=on
dos=high,umb
files=60
buffers=10
stacks=9,256
lastdrivehigh=z
shell=c:\dos\command.com /p c:\dos /e:1024 /z

[dosumb]
include dos
device=c:\win31\himem.sys
device=c:\win31\emm386.exe noems i=b000-b7ff x=d800-dfff

[dosems]
include dos
device=c:\win31\himem.sys
device=c:\win31\emm386.exe 1024 ram i=b000-b7ff x=d800-dfff frame=e000

[dosansi]
include dosumb
devicehigh=c:\dos\ansi.sys

[dos386max]
include dos
device=d:\tools\386max\386max.sys

[dosdbg]
device=c:\s-ice\s-ice.exe /tra 1000
include dos

[lanman20]
include dosumb
include lanman20_drivers
include lanman_logon

[lanman20_drivers]
devicehigh=c:\lanman\drivers\protman\protman.dos /i:c:\lanman
devicehigh=c:\lanman\drivers\ethernet\ub\ubnei.dos
devicehigh=c:\lanman\drivers\protocol\netbeui\netbeui.dos
devicehigh=c:\lanman\drivers\protocol\xns\ubxpw.dos
devicehigh=c:\lanman\drivers\protocol\xns\ubloop.dos
installhigh c:\lanman\drivers\protman\netbind.exe

[lanman21]
include dosumb
include lanman21_drivers
include lanman_logon

[lanman21nb]
include dosumb
include lanman21_drivers
install c:\lanman\netprog\load.com netbeui
include lanman_logon

[lanman21xm]
include dosumb
install c:\lanman\xnsmono\loadniu.exe -r -d -m:d8 -i:5 -p:4 c:\lanman\xnsmono\exniu2.xfm c:\lanman\xnsmono\1a.lc
install c:\lanman\xnsmono\xnsbios.exe -m:d8 -i:5 -p:4
include lanman_logon

[lanman21dbg]
device=c:\s-ice\s-ice.exe /tra 1000
include dos
include lanman21_drivers
include lanman_logon

[lanman21_drivers]
devicehigh=c:\lanman\drivers\protman\protman.dos /i:c:\lanman
devicehigh=c:\lanman\drivers\ethernet\ub\ubnei.dos
device=c:\lanman\drivers\protocol\ubxns\ubxps.dos
install c:\lanman\netprog\netbind.com

[lanman_logon]
install c:\lanman\netprog\net.exe start workstation
install c:\lanman\netprog\net.exe logon jeffpar2 /y
;install c:\lanman\netprog\net.exe use k: \\jeffpar\astro dos6
;install c:\lanman\netprog\net.exe use j: \\jeffpar\cougar dos7

[winball]
include dosumb
include lanman21_drivers
devicehigh=c:\win31\redirdrv.sys
devicehigh=c:\win31\system\vnbhlp.dos
shell=c:\dos\command.com /p c:\dos /e:1024 /z /k windb
set path=d:\tools\dos;d:\tools\bound;d:\tools\windev;c:\win31;c:\dos

[cougar]
include dosumb
include lanman21_drivers
devicehigh=c:\win31\redirdrv.sys
devicehigh=c:\win31\system\vnbhlp.dos
shell=c:\dos\command.com /p c:\dos /e:1024 /z /k cougar7
set path=d:\tools\dos;d:\tools\bound;d:\tools\windev;c:\win31;c:\dos;d:\cougar

[common]
installhigh d:\tools\dos\keyfix.com
installhigh c:\win31\mouse.com
installhigh c:\dos\share.exe
installhigh c:\win31\smartdrv.exe 1024
installhigh c:\dos\doskey.com /a /e /x /p /k:128 /f:d:\tools\dos\aliases
install c:\dos\mode.com con:rate=30 delay=1
install d:\tools\dos\50.com

Wrapping Up Support for FAT

Tue, 05 Sep 2023 10:00:00 +0000

This will probably be the final post in my “trilogy” of posts about the PC.js command-line utility, now that I’ve (hopefully) finished ironing out most of the wrinkles. I’ve improved FAT12 and FAT16 support, so when pc.js builds either a standard or custom FAT disk image, it should be compatible with whatever version of PC DOS, MS-DOS, or COMPAQ DOS you select.

BTW, there’s no FAT32 support. FAT32 arrived on the scene in 1996, and my focus here at “PCjs HQ” is generally on stuff older than that and/or stuff that personally interests me. So, apologies in advance.

Let’s start with a quick recap of what you can now do with PC.js:

Start IBM 5150/5160/5170 and COMPAQ DeskPro 386 machines from the command-line
Start any machine that has a PCjs XML configuration file, like this IBM PC XT or this PDP-11/20
Boot any version of PC DOS and MS-DOS operating systems
Build bootable floppy images and hard disk images from any supported version of DOS
Load any diskette from the large collection of PCjs software diskette images
Define custom drive types, using any disk geometry the PCjs machine controller will support
Customize FAT disk images, specifying 12 or 16-bit FAT, cluster size, root directory size, and more
Seamlessly run local programs (eg, ls, vi, cp) and access local files from the DOS command prompt
Automatically sync changes between your local file system and the pc.js disk drive

In some ways, pc.js is a culmination of what I started 11 years ago with JavaScript-based machine emulation on the PCjs website (although back then, the website was jsmachines.net; it didn’t become pcjs.org until 2013).

Because I chose to write everything in vanilla JavaScript (sometimes jokingly referred to as Vanilla JS) and not some other language that could be compiled natively and transpiled to JavaScript or WebAssembly, creating a command-line version of PCjs has meant relying on Node.js, and while that works well, it is a rather heavyweight solution.

But I’m OK with that, because PCjs has always been focused on machines from the 1980s and early 1990s, which didn’t run very fast anyway. 16Mhz was pretty respectable back then, and it turns out that JavaScript has no problem simulating that level of performance.

Also, since Node.js, several interesting JavaScript runtime alternatives have popped up, like Deno and Bun. I haven’t tried running pc.js with either of them yet, but I look forward to giving both of them a try. Browsers still rely on JavaScript, and JavaScript doesn’t appear to be going away any time soon.

And JavaScript runtime overhead isn’t actually responsible for the biggest part of PCjs startup time. That honor goes to the PC’s own ROM BIOS “POST” or Power-On Startup Tests – which PCjs faithfully emulates.

Fortunately, there’s a simple work-around for reducing PC startup time: the default machine used by pc.js – a COMPAQ DeskPro 386 – comes with a state file that restores the machine’s state to the point where it’s about to read the boot sector from the machine’s hard disk. So not only are all power-on diagnostics bypassed, but all the floppy drive seek test and boot operations are skipped as well.

Retro Software Development

I really wanted to leverage all the browser-based code I had written over the years to solve a fairly simple problem: compile/assemble/link and run/debug DOS software from a modern non-DOS command-line. In other words, I wanted to integrate a simple retro-software-development environment into my existing macOS dev environment.

And while working on pc.js, I ran into the perfect example. I needed to create my own slightly modified version of the DOS Master Boot Record (MBR), which meant I needed to disassemble an existing MBR, recreate the source as an .ASM file, and then run it through the usual DOS tool chain (masm, link, exe2bin). And it since it would be an iterative process (assemble, test, fix, re-assemble), the easier the process, the better.

Here’s how I was able to do that using pc.js:

In the screen capture above, I start by using my diskimage.js utility to download and extract a complete DOS dev environment from an existing PCjs hard disk image into a directory named test.

Then I cd test and run pc.js, which builds a bootable hard disk image with all the files and folders in test, and then boots it. From that point on, until I run the quit command, I’m running DOS (the default is MS-DOS 3.30). And when I quit, any files that were added/changed/deleted are automatically updated in the local file system.

I can also run a selection of non-DOS commands to access files from the local file system. Every time I type ls or vi, for example, a lot of work happens behind the scenes: the machine is shut down, all file changes are synced, then the non-DOS command is run, and when it exits, the machine’s hard disk is recreated and the machine is restarted.

Booting Different Versions of DOS

The --sys and --ver options control the version of DOS used to the build its bootable hard disk – or bootable floppy disk if you specify --floppy.

By default, pc.js will build a 10Mb hard disk – or the largest floppy disk that your chosen version of DOS supports. If you want something bigger or smaller, use the --target option; it supports either kilobytes (eg, --target=160K) or megabytes (eg, --target=20M).

pc.js will “auto-build” only one disk for a machine: either a single-partition hard disk (C:) or a floppy disk (A:). If you want your machine to automatically load other disks into other drives, you’ll have to create a custom machine configuration file that uses prebuilt disk images.

The whole point of the “auto-build” drive is to mirror the files in your current directory (or whatever directory you specify with --dir). Since you only have one current directory at any point in time, it doesn’t really make sense for pc.js to manage more than one automatically built drive.

However, you can load any diskette image into drive A: or B: at any time using the load command that pc.js includes with every disk image it builds. Details of the load command were covered in an earlier blog post.

Customizing the Drive Type

The IBM PC XT, IBM PC AT, and COMPAQ DeskPro 386 are three examples of machines that supported hard disks, and PCjs includes built-in support for all their respective Hard Drive Types. For example, if you want your machine to be an PC AT with a Type 2 hard disk, run:

% pc.js ibm5170 --drivetype=2 
[Press CTRL-D to enter command mode]

C:\>load info

AT drive type 2, CHS 615:4:17, 20.4Mb
16-bit FAT, 2048-byte clusters, 10398 clusters
82 FAT sectors (x2), 64 root sectors (1024 entries)
41752 total sectors, 41523 data sectors, 21295104 data bytes

NOTE: load info is a variation of the load command that displays information about the built-in disk image. I had considered making a separate info utility to do that, since the purpose of the load utility is loading diskette images into drives A: and B:, but I was lazy.

If you don’t remember your favorite PC AT drive type, you can just give pc.js a target size and let it search the machine’s drive table for the closest match:

% pc.js ibm5170 --target=30.6M
warning: 62 FAT sectors allocated, but only 61 are required
[Press CTRL-D to enter command mode]

C:\>load info

AT drive type 3, CHS 615:6:17, 30.6Mb
16-bit FAT, 2048-byte clusters, 15608 clusters
124 FAT sectors (x2), 64 root sectors (1024 entries)
62628 total sectors, 62315 data sectors, 31965184 data bytes

Note that the drive tables of AT-class machines usually didn’t define any drives smaller than 10Mb, and the smallest drive type the PC XT defined was 5Mb, so using --target with smaller sizes won’t give you smaller drives on those machines. To do that, you must bypass the machine’s drive table by adding --controller=pcjs to the command-line. For example:

% pc.js load info --sys=pcdos --ver=3.0 --controller=pcjs --target=1M
[Press CTRL-D to enter command mode]

C>ECHO OFF

PCJS drive type 0, CHS 61:2:17, 1.0Mb
12-bit FAT, 1024-byte clusters, 1012 clusters
3 FAT sectors (x2), 7 root sectors (112 entries)
2040 total sectors, 2026 data sectors, 1036288 data bytes

pc.js will calculate a drive geometry that matches your target size as closely as possible (1Mb in this case), and then set up a custom PCJS drive type.

Finally, for complete control of a custom drive type, you can choose any drive geometry you want by passing a “cylinders:heads:sectors” (CHS) triplet to the --drivetype parameter, and since that automatically uses a PCJS drive type, you don’t need to include --controller=pcjs.

For example:

% pc.js ibm5170 --drivetype=615:5:17
[Press CTRL-D to enter command mode]

C:\>load info

PCJS drive type 0, CHS 615:5:17, 25.5Mb
16-bit FAT, 2048-byte clusters, 13003 clusters
102 FAT sectors (x2), 64 root sectors (1024 entries)
52190 total sectors, 51921 data sectors, 26630144 data bytes

C:\>chkdsk
Volume TEST        created Aug 30, 2023 11:10a

 26630144 bytes total disk space
    90112 bytes in 9 hidden files
    45056 bytes in 22 directories
  4306944 bytes in 257 user files
 22188032 bytes available on disk

   655360 bytes total memory
   586256 bytes free

Custom drive types work thanks to the Master Boot Record that I created specifically for pc.js. It operates exactly like a normal DOS MBR, with the additional ability to install custom drive tables. And since this is a fully PC-compatible solution, it should work in the “real world” as well – as long as you don’t select a drive geometry that doesn’t work with your actual hardware.

One example of a broken machine/drive combination would be any IBM PC XT machine attempting to boot from a drive using something other than 17 sectors/track. The XT BIOS does support custom drive tables, but that support is hard-coded to disks with only 17 sectors/track.

Customizing FAT Volumes

In the past, PCjs only needed to build a limited number of FAT volume types, so it used a predefined set of BPBs. BPBs (BIOS Parameter Blocks) are data structures introduced by DOS 2.00 and embedded in the DOS boot sector to describe the structure of the disk and the FAT file system on it. For reference, here’s how PCjs defines the BPB (see diskinfo.js):

OPCODE:         0x000,      // 1 byte for an x86 JMP opcode, followed by a 1 or 2-byte offset
OEM:            0x003,      // 8 bytes (eg, "IBM  2.0")
SECBYTES:       0x00B,      // 2 bytes: bytes per sector (eg, 0x200 or 512)
CLUSSECS:       0x00D,      // 1 byte: sectors per cluster (eg, 1)
RESSECS:        0x00E,      // 2 bytes: reserved sectors; ie, # sectors preceding the first FAT, usually just the boot sector (eg, 1)
FATS:           0x010,      // 1 byte: FAT copies (eg, 2)
DIRENTS:        0x011,      // 2 bytes: root directory entries (eg, 0x40 or 64)
DISKSECS:       0x013,      // 2 bytes: number of sectors (eg, 0x140 or 320); if zero, refer to LARGESECS
MEDIA:          0x015,      // 1 byte: media ID (eg, 0xF8); should also match the first byte of the FAT (aka FAT ID)
FATSECS:        0x016,      // 2 bytes: sectors per FAT (eg, 1)
TRACKSECS:      0x018,      // 2 bytes: sectors per track (eg, 8)
DRIVEHEADS:     0x01A,      // 2 bytes: number of heads (eg, 1)
HIDDENSECS:     0x01C,      // 2 bytes (DOS 2.x) or 4 bytes (DOS 3.31 and up): number of hidden sectors (0 for non-partitioned media)
BOOTDRIVE:      0x01E,      // 1 byte (DOS 2.x): BIOS boot drive # (eg, 0x00 or 0x80)
BOOTHEAD:       0x01F,      // 1 byte (DOS 2.x): BIOS boot head # (0-based)
/*
 * NOTE: DOS 2.0 also stores the number of sectors in the BIOS file (eg, IO.SYS, IBMBIO.COM) in the byte at offset
 * 0x020 (LARGESECS), followed by a custom 11-byte Diskette Parameter Table (DPT) at offsets 0x021 through 0x0x2B, which
 * it promptly points the DPT vector 0x1E (0:0078h) to.
 */
LARGESECS:      0x020,      // 4 bytes (DOS 3.31 and up): number of sectors if DISKSECS is zero

Most BPB definitions start at offset 0x00B (ie, they don’t include the OPCODE or OEM fields), but I do include them because those fields are actually used by DOS for BPB validation purposes, so their purpose is really inseparable from the rest of the BPB.

My predefined BPBs included all the standard PC floppy disk formats (160K, 180K, 320K, 360K, 720K, 1200K, and 1440K) as well as two hard disk formats (10Mb and 20Mb) – all formats that also used 12-bit FATs.

However, I wanted the pc.js utility to be able to accommodate a much wider range of hard disk formats, along with any version of DOS that supported those formats. This, in turn, meant adding some features I hadn’t needed until now: support for 16-bit FATs (added in DOS 3.00), and support for disks with more than 64K total sectors (added in DOS 3.31).

Neither of those features were difficult to add. Difficulties only arose when actually trying to boot FAT volumes built with custom settings. My troubles started with PC DOS 2.00 – the very first version of DOS to support hard disks – because even though it faithfully places a BPB on every hard disk it formats, it doesn’t actually pay attention to many of the values stored in the BPB.

In PC DOS 2.00, the code that determines a disk’s cluster size and root directory size begins below, where it first scans the MBR for FAT12 partition type 01h. I’ve disassembled and commented the code to make it a bit more readable:

&0070:093B BBC201           MOV      BX,01C2            ; BX -> partition record + 4 (it actually starts at 1BEh)
&0070:093E 26803F01         CMP      ES:[BX],01         ; is partition type 01h?
&0070:0942 740B             JZ       094F               ; if so, jump
&0070:0944 83C310           ADD      BX,0010            ; otherwise, BX -> next partition record
&0070:0947 81FB0202         CMP      BX,0202            ; is BX now beyond the end of the partition table?
&0070:094B 75F1             JNZ      093E               ; jump if not
&0070:094D F9               STC                         ; otherwise, error (partition with type 01h is missing)
&0070:094E C3               RET                         ;
&0070:094F 268B4704         MOV      AX,ES:[BX+04]      ; AX = LBA of first partition sector (assumes a 16-bit value)
&0070:0953 894511           MOV      [DI+11],AX         ; (stash LBA)
&0070:0956 268B4708         MOV      AX,ES:[BX+08]      ; AX = total sectors in partition (assumes a 16-bit value)
&0070:095A 3D4000           CMP      AX,0040            ; is total less than 64 sectors?
&0070:095D 72EE             JC       094D               ; if so, jump (error)
&0070:095F 894508           MOV      [DI+08],AX         ; (stash total sectors)
&0070:0962 B90001           MOV      CX,0100            ; CH = default sectors/cluster, CL = clusters-to-sectors shift count
&0070:0965 BA4000           MOV      DX,0040            ; DX = default number of root directory entries
&0070:0968 3D0002           CMP      AX,0200            ; is total sectors <= 512?
&0070:096B 7629             JBE      0996               ; yes (that's only a 256Kb disk)
&0070:096D 02ED             ADD      CH,CH              ; otherwise, default sectors/cluster is now 2 (1K cluster size)
&0070:096F FEC1             INC      CL                 ; shift count to match
&0070:0971 BA7000           MOV      DX,0070            ; DX = 70h (112 root directory entries)
&0070:0974 3D0008           CMP      AX,0800            ; is total sectors <= 2048?
&0070:0977 761D             JBE      0996               ; yes (that's only a 1Mb disk)
&0070:0979 02ED             ADD      CH,CH              ; otherwise, default sectors/cluster is now 4 (2K cluster size)
&0070:097B FEC1             INC      CL                 ; shift count to match
&0070:097D BA0001           MOV      DX,0100            ; DX = 100h (256 root directory entries)
&0070:0980 3D0020           CMP      AX,2000            ; is total sectors <= 8192?
&0070:0983 7611             JBE      0996               ; yes (that only a 4Mb disk)
&0070:0985 02ED             ADD      CH,CH              ; otherwise, default sectors/cluster is now 8 (4K cluster size)
&0070:0987 FEC1             INC      CL                 ; shift count to match
&0070:0989 03D2             ADD      DX,DX              ; DX = 200h (512 root directory entries)
&0070:098B 3DA87F           CMP      AX,7FA8            ; is total sectors <= 32680?
&0070:098E 7606             JBE      0996               ; yes (that's only a 16Mb disk)
&0070:0990 02ED             ADD      CH,CH              ; otherwise, default sectors/cluster is now 16 (8K cluster size)
&0070:0992 FEC1             INC      CL                 ; shift count to match
&0070:0994 03D2             ADD      DX,DX              ; DX = 400h (1024 root directory entries)
&0070:0996 895506           MOV      [DI+06],DX         ; (stash defaults in internal structure)
&0070:0999 886D02           MOV      [DI+02],CH

So, based solely on total sectors, DOS 2.00 has decided what the cluster size and root directory should be – which means that no matter what values your FAT volume actually uses and has actually stored in the BPB, DOS 2.00 will crash if those values don’t match its defaults. There will be no error message, and unless you have a debugger running, the machine will appear hung.

DOS 2.00 then goes on to calculate how many “sectors per FAT” there should be. It does this by dividing “total sectors” by “sectors per cluster” (which it does by shifting right, since “sectors per cluster” is always a power of 2). That provides an upper limit for total clusters, which it then rounds up to the nearest even number, multiplies by 1.5 (to yield total cluster bytes), and then divides by 512:

&0070:099C 33DB             XOR      BX,BX
&0070:099E 8ADD             MOV      BL,CH
&0070:09A0 4B               DEC      BX
&0070:09A1 03D8             ADD      BX,AX
&0070:09A3 D3EB             SHR      BX,CL
&0070:09A5 43               INC      BX
&0070:09A6 80E3FE           AND      BL,FE
&0070:09A9 8BF3             MOV      SI,BX
&0070:09AB D1EB             SHR      BX,1
&0070:09AD 03DE             ADD      BX,SI
&0070:09AF 81C3FF01         ADD      BX,01FF
&0070:09B3 D0EF             SHR      BH,1
&0070:09B5 887D0B           MOV      [DI+0B],BH

This is also one of the many places where DOS also assumes 512-bytes sectors, ignoring the “bytes per sector” field in the BPB.

Since the above calculation of “sectors per FAT” doesn’t take into account any other sector usage (eg, reserved sectors, root directory sectors, not to mention the FAT sectors themselves, of which there are invariably 2 copies), there are going to be situations where DOS allocates more sectors per FAT than the number of available clusters actually requires. And when presented with such a situation, if we don’t over-allocate our FAT as well, DOS 2.00 will again crash – because, in addition to ignoring “bytes per sector”, “sectors per cluster”, and “root directory entries” in the BPB, DOS 2.00 also ignores “sectors per FAT”, relying instead on its own calculation.

To confirm this, I tested a drive configuration (162 cylinders, 4 heads, and 17 sectors/track) which PC DOS 2.00 would format as a 12-bit FAT with 4K clusters, 32 root directory sectors (for a total of 512 entries), and 5 sectors per FAT – yielding a disk with 1361 available clusters. Except that 1361 clusters only requires a 2045-byte FAT, which fits perfectly in 4 sectors, with 3 bytes to spare. However, when I built such a disk with only 4 sectors per FAT, DOS failed to boot.

Here’s how I built it using pc.js:

% pc.js --sys=pcdos --ver=2.00 --drivetype=162:4:17 --trim --save=test.img

The undocumented --trim flag tells pc.js to bypass its normal DOS-compatibility rules and build/format the disk with an “optimized” 12-bit FAT, and the --save option saves the disk image without starting a machine. And although DOS 2.00 didn’t like it, test.img was an otherwise perfectly valid and usable disk image, and fsck_msdos on macOS reported no problems.

It’s understandable that DOS 2.00 would be skeptical of its own BPBs, in part because BPBs were a new feature that probably evolved during the development of DOS 2.00, so they would have been dealing with disks with no BPBs, out-dated BPBs, or even invalid BPBs. However, perhaps the biggest problem was FDISK, because whenever FDISK created a DOS partition, it would simply update the partition table in the Master Boot Record and then reboot, leaving the partition’s boot sector and any BPB it previously contained in place. And that old BPB might be completely inappropriate.

On the other hand, I think DOS 2.00 could have made an effort to validate the BPB, ensuring that its drive parameters matched those in the Master Boot Record before relying on it. But that didn’t happen. To avoid a potential mess, DOS took the easy way out and simply used a set of FAT parameters based entirely on disk size.

Overview of the FAT File System

Before diving into more examples of how picky DOS was about mounting FAT disks, I want to take a step back for a minute and talk about a document that Microsoft first released in the late 1990s called FAT: General Overview of On-Disk Format. The version here (1.03) is from 2000, but as far as FAT12 and FAT16 support is concerned, there are no substantive differences between it and the 1999 (1.02) version. Of course, in typical fashion, Microsoft no longer makes any version of the document available.

Anyway, while working on pc.js, I referred extensively to the FAT12 and FAT16 sections of that document. It reinforced some very important rules, such as:

This is the one and only way that FAT type is determined. There is no such thing as a FAT12 volume that has more than 4084 clusters. There is no such thing as a FAT16 volume that has less than 4085 clusters or more than 65,524 clusters. There is no such thing as a FAT32 volume that has less than 65,525 clusters. If you try to make a FAT volume that violates this rule, Microsoft operating systems will not handle them correctly because they will think the volume has a different type of FAT than what you think it does.

This document was as close to a “gold standard” for the FAT file system as the world ever got – at least from Microsoft. Even so, it does gloss over some important details.

One such detail is when and how a volume should be formatted with FAT12 or FAT16. Actually, let’s break that question into smaller questions:

When formatting a disk, when should you choose FAT12 or FAT16?
When formatting a disk with FAT12 or FAT16, how should you select cluster size?
When mounting a disk, how do you tell whether it’s FAT12 or FAT16?

Regarding question #1, the document does say this:

There is no dynamic computation for FAT12. For the FAT12 formats, all the computation for BPB_SecPerClus and BPB_FATSz16 was worked out by hand on a piece of paper and recorded in the table (being careful of course that the resultant cluster count was always less than 4085). If your media is larger than 4 MB, do not bother with FAT12. Use smaller BPB_SecPerClus values so that the volume will be FAT16.

So that kind of answers the question: maybe use FAT12 if the volume is 4Mb or smaller.

With respect to question #2, there’s no sign of “the table” that DOS used to choose cluster size for FAT12. In DOS 2.00, as we saw above, there was only a series of disk size comparisons, which can be summarized in a table:

Disk Size    Cluster Size    Root Directory Size
---------    ------------    -------------------
 <= 256Kb       1 sector         64 root entries
 <=   1Mb       2 sectors       112 root entries
 <=   4Mb       4 sectors       256 root entries
 <=  16Mb       8 sectors       512 root entries
  >  16Mb      16 sectors      1024 root entries

And starting with DOS 3.00, since FAT16 was now preferred, “the table” for FAT12 was reduced to a single entry that always selected 4K clusters and was used only if the disk contained 32680 (0x7FA8) sectors or less (ie, 16340Kb or approximately 16Mb).

As for FAT16 cluster sizes, the document does provide a table:

Disk Size     Cluster Size    Root Directory Size
----------    ------------    -------------------
<=  4200Kb             N/A              Use FAT12
<= 16340Kb       2 sectors       512 root entries
<=   128Mb       4 sectors       512 root entries
<=   256Mb       8 sectors       512 root entries
<=   512Mb      16 sectors       512 root entries
<=  1024Mb      32 sectors       512 root entries
<=  2048Mb      64 sectors       512 root entries

And except for the fact that DOS always used FAT12 in the second case as well, that table more or less matches the criteria that DOS eventually used, once disks with those sizes became available.

Note that when DOS 3.00 introduced FAT16 in 1984, the PC BIOS could not support drives with more than 1024 cylinders, 16 heads, and 63 sectors per track, imposing an upper limit of 504Mb. On top of that, DOS versions 2.00 through 3.30 couldn’t support partitions with more 64K sectors, which imposed a volume limit of 32Mb. This is why DOS 3.00 didn’t perform any cluster size calculations: if the disk was big enough to warrant FAT16, then it simply always used 2K clusters. However, as demand for larger disks grew, techniques like CHS translation (that allowed a maximum of 256 logical heads without requiring any changes to the PC BIOS interface) provided support for much larger disks (up to 8192Mb or 8Gb), and then when DOS 3.31 added support for volumes with more than 64K sectors, later versions of DOS had to make more judicious decisions about cluster size.

Question #3 is never really discussed. You might assume the rule is simply that if the partition type in the MBR is 01h, the partition is FAT12, and if it’s 04h (or 06h for disks with more than 64K sectors), the partition is FAT16. But it’s not that simple, and sadly, no one ever thought to add anything to the BPB to clearly indicate the type of FAT – a rather vital piece of information. I’ve learned the hard way that a 10Mb disk formatted with FAT16 and more than 4084 clusters and clearly marked with partition type 04h will still be treated by DOS 3.x as a FAT12 volume by default. More on that later.

Finally, even though Microsoft “sanitized” the document (by which I mean sprinkled a liberal dose of “legalese” and then completely removed any hint of who actually wrote or contributed to it), it’s pretty clear to me who wrote it: Aaron Reynolds.

A Few Words About Aaron Reynolds

I’m sure there are still living current or former Microsoft employees who could easily confirm that Aaron wrote the document, and maybe one will pop out of the woodwork and do just that, but sadly, Aaron isn’t one of them. He passed away in 2008.

Aaron had a long and legendary career at Microsoft, working on DOS 1.1 and subsequent versions, and well as many versions of Windows. His name appears several times in “The MS-DOS Encyclopedia”, which even includes a hand-drawn diagram by him:

My path occasionally crossed Aaron’s while we were both working on Windows 95, and I even share credit with him on the “Common Name Space For Long And Short Filenames” Patent (No. 5,579,517) – although to be honest, my contribution to that “invention” was pretty minimal. All I recall are hallway conversations about the viability of combinations of attribute bits, including the volume label bit, to hide long filename entries from previous versions of DOS.

Aaron was very smart, opinionated, and intense. One way that intensity came out was a tendency to really “hammer” on certain points, probably because he was tired of seeing other people repeatedly making common mistakes. And there are passages in the FAT: General Overview of On-Disk Format document that strike me as “vintage Aaron Reynolds”.

For example:

There is considerable confusion over exactly how [FAT Type Determination] works, which leads to many “off by 1”, “off by 2”, “off by 10”, and “massively off” errors. It is really quite simple how this works. The FAT type–one of FAT12, FAT16, or FAT32–is determined by the count of clusters on the volume and nothing else.

Please read everything in this section carefully, all of the words are important. For example, note that the statement was “count of clusters.” This is not the same thing as “maximum valid cluster number,” because the first data cluster is 2 and not 0 or 1.

and this:

Now we can determine the FAT type. Please note carefully or you will commit an off-by-one error! In the following example, when it says <, it does not mean <=. Note also that the numbers are correct. The first number for FAT12 is 4085; the second number for FAT16 is 65525. These numbers and the ‘<’ signs are not wrong.

There’s even one paragraph that simply says:

Please don’t draw an incorrect conclusion here.

I can’t read any of those passages without smiling.

There isn’t much about Aaron online, although I did find a nice tribute to him from Charles Wright Academy. I’ll end my own tiny tribute with a short clip of Aaron from July 14, 1995, as he was looking forward to the imminent release of Windows 95 and talking about “harsh email” (I don’t know who taped this, but I’m hopeful they won’t mind it being shared here).

More Fun with DOS and FAT Volumes

I’ve already beaten PC DOS 2.00 to death, so let’s move on to PC DOS 3.00. I’d mentioned this earlier:

A 10Mb disk formatted with FAT16 (ie, with more than 4084 clusters and clearly marked with partition type 04h) will still be treated by DOS 3.x as a FAT12 volume by default.

To test this, I ran pc.js in a directory with a small number of files, requesting a drive with PC DOS 3.00 and a 16-bit FAT:

% pc.js ibm5170 --sys=pcdos --ver=3.00 --fat=16
warning: 16-bit FAT replaced with 12-bit FAT
[Press CTRL-D to enter command mode]

C:\>load info

AT drive type 1, CHS 306:4:17, 10.2Mb
12-bit FAT, 4096-byte clusters, 2586 clusters
8 FAT sectors (x2), 32 root sectors (512 entries)
20740 total sectors, 20691 data sectors, 10592256 data bytes

You can see we successfully booted to a C:\> prompt, but load info told us that the disk was built as FAT12 instead of FAT16. This was because pc.js tries to stick to historical defaults, and 10Mb disks were “historically” formatted as FAT12.

You may recall that the FAT: General Overview of On-Disk Format said:

If your media is larger than 4 MB, do not bother with FAT12.

Except that PC DOS 2.00 did bother with FAT12 on a 10Mb disk – because, well, FAT12 was all it could do. But even when PC DOS 3.00 introduced FAT16, it would still format a 10Mb disk as FAT12. It had to use 4K clusters in order to keep total clusters under 4085, but it preferred FAT12 over 2K clusters – future recommendations notwithstanding.

Anyway, we can force pc.js to build a FAT16 disk. We just have to also specify a cluster size (2K) that will produce too many clusters for FAT12 to handle, forcing the use of FAT16:

% pc.js ibm5170 --sys=pcdos --ver=3.00 --fat=16:2048            
[Press CTRL-D to enter command mode]

stopped (32233718 cycles, 4041 ms, 7976669 hz)
AX=0000 BX=FFFF CX=0342 DX=4F03 SP=00C2 BP=0004 SI=FFFF DI=1F64 
SS=9E98 DS=0070 ES=9C72 PS=0246 V0 D0 I1 T0 S0 Z1 A0 P1 C0 
&017D:4159 0000             ADD      [BX+SI],AL
[Type help for list of commands, CTRL-C to terminate]
>> load info
AT drive type 1, CHS 306:4:17, 10.2Mb
16-bit FAT, 2048-byte clusters, 5164 clusters
21 FAT sectors (x2), 32 root sectors (512 entries)
20740 total sectors, 20665 data sectors, 10575872 data bytes

And the machine “crashes” (well, it executes a suspicious instruction at 17D:4159, so the PCjs debugger stops it).

It turns out this happened because I put “IBM 3.0” in the BPB, which seemed logical, since “IBM 2.0” would imply that PC DOS 2.x formatted the disk, but since the disk was using FAT16, it couldn’t have. And yet, ironically, by putting the “old” OEM signature in the BPB, PC DOS 3.00 honors the BPB values, and then later notices that “total clusters” is greater than 4085, so it marks the volume as FAT16 after all, and life is good.

Here’s the code where PC DOS 3.00 inspects the MBR and then the BPB in the boot sector. It appears that the code originally intended to honor a BPB with an “IBM 3.0” signature, but a mistake in the code made that impossible. Again, I’ve sprinkled my own comments throughout the disassembled code to help make it more readable:

&0070:1438 BBC203           MOV      BX,03C2            ; BX -> partition table entry + 4
&0070:143B 26803F01         CMP      ES:[BX],01         ; type 1? (FAT12)
&0070:143F 7411             JZ       1452               ; yes
&0070:1441 26803F04         CMP      ES:[BX],04         ; type 4? (FAT16)
&0070:1445 740B             JZ       1452               ; yes
&0070:1447 83C310           ADD      BX,0010            ; BX -> next entry
&0070:144A 81FB0204         CMP      BX,0402            ; more entries?
&0070:144E 75EB             JNZ      143B               ; yes
&0070:1450 F9               STC                         ; no, and we never found an entry, so return error (carry set)
&0070:1451 C3               RET     

&0070:1452 52               PUSH     DX                 ; save drive (DL)
&0070:1453 268B4704         MOV      AX,ES:[BX+04]      ;
&0070:1457 268B5706         MOV      DX,ES:[BX+06]      ; DX:AX = starting LBA of partition
&0070:145B 26034708         ADD      AX,ES:[BX+08]      ;
&0070:145F 2613570A         ADC      DX,ES:[BX+0A]      ; DX:AX = ending LBA of partition + 1
&0070:1463 7405             JZ       146A               ; are the top 16 bits of the sum zero?
&0070:1465 800ECC1080       OR       [10CC],80          ; no, so set 80h in "drive byte" (possible error bit)
&0070:146A 5A               POP      DX                 ; recover drive (DL)

&0070:146B 268B4704         MOV      AX,ES:[BX+04]      ; AX = starting LBA (which we presume to be only 16 bits)
&0070:146F 894511           MOV      [DI+11],AX         ; stash it
&0070:1472 268B4708         MOV      AX,ES:[BX+08]      ; AX = total sectors in partition
&0070:1476 3D4000           CMP      AX,0040            ; is total less than 64 sectors?
&0070:1479 72D5             JC       1450               ; if so, jump (error)
&0070:147B 894508           MOV      [DI+08],AX         ; (stash total sectors)
;
; Change from DOS 2.00: Read the partition's boot sector so we can access the BPB.
; What follows is a bunch of instructions that should have been a subroutine (ie, to
; convert the partition's starting LBA to C:H:S values).
;
; Also, it's a bit unfortunate that the volume's boot sector is already sitting in memory.
; Of course, that's only true for the first disk drive, but in the case of the first drive,
; this code is a complete waste of time.
;
&0070:147E 50               PUSH     AX                 
&0070:147F 52               PUSH     DX
&0070:1480 8B4511           MOV      AX,[DI+11]         ; AX = starting LBA again
&0070:1483 33D2             XOR      DX,DX              ; 
&0070:1485 8AFE             MOV      BH,DH
&0070:1487 8A5D0D           MOV      BL,[DI+0D]         ; BX = sectors per track
&0070:148A F7F3             DIV      BX                 ; divide DX:AX by sectors per track
&0070:148C 8ACA             MOV      CL,DL
&0070:148E FEC1             INC      CL
&0070:1490 99               CWD     
&0070:1491 8A5D0F           MOV      BL,[DI+0F]         ; BX = number of heads
&0070:1494 F7F3             DIV      BX
&0070:1496 D0CC             ROR      AH,1
&0070:1498 D0CC             ROR      AH,1
&0070:149A 80E4C0           AND      AH,C0
&0070:149D 0ACC             OR       CL,AH
&0070:149F 8AE8             MOV      CH,AL
&0070:14A1 58               POP      AX
&0070:14A2 8AF2             MOV      DH,DL
&0070:14A4 8AD0             MOV      DL,AL
&0070:14A6 33DB             XOR      BX,BX
&0070:14A8 B80102           MOV      AX,0201
&0070:14AB CD13             INT      13
&0070:14AD 58               POP      AX
;
; At this point, the partition's boot sector should be at ES:0 (since BX was zero);
; these instructions could have been a bit smaller if they had used ES:BX addressing.
;
&0070:14AE 26813E03004942   CMP      ES:[0003],4249     ; does the OEM signature start with  "IB"?
&0070:14B5 751C             JNZ      14D3               ; no
&0070:14B7 26813E05004D20   CMP      ES:[0005],204D     ; does it continue with "M "?
&0070:14BE 7513             JNZ      14D3               ; no
&0070:14C0 26813E0800322E   CMP      ES:[0008],2E32     ; does it continue with "2."?
&0070:14C7 750A             JNZ      14D3               ; no
&0070:14C9 26803E0A0030     CMP      ES:[000A],30       ; is the "2." followed by "0"?
&0070:14CF 7505             JNZ      14D6               ; no
&0070:14D1 EB14             JMP      14E7               ; yes
&0070:14D3 EB4C             JMP      1521
&0070:14D5 90               NOP     
;
; This code is prepared to deal with a signature of "IBM  3.0" and jump to 14E7
; just as previous code did for "IBM  2.0", but technically, that will never happen,
; because previous code already gave up when the signature didn't contain "2.".
;
&0070:14D6 26813E0800332E   CMP      ES:[0008],2E33
&0070:14DD 75F4             JNZ      14D3
&0070:14DF 26803E0A0030     CMP      ES:[000A],30
&0070:14E5 75EC             JNZ      14D3
;
; This code is executed ONLY if the OEM signature contained "IBM  2.0"
; (well, technically, the previous code didn't care what came before the "2";
; normally it's a space but it could be anything).
;
; Anyway, this is the only code that actually honors the BPB values.
;
&0070:14E7 26A11300         MOV      AX,ES:[0013]       ; AX = total sectors
&0070:14EB 48               DEC      AX                 ; subtract 1 (assumes reserved sectors == 1?)
&0070:14EC 268B161600       MOV      DX,ES:[0016]       ; DX = sectors per FAT
&0070:14F1 89550B           MOV      [DI+0B],DX         ; (stash it)
&0070:14F4 D1E2             SHL      DX,1               ; double it (assumes number of FATs == 2?)
&0070:14F6 2BC2             SUB      AX,DX              ; subtract from total sectors
&0070:14F8 268B161100       MOV      DX,ES:[0011]       ; DX = number of directory entries
&0070:14FD 895506           MOV      [DI+06],DX         ; (stash it)
&0070:1500 B104             MOV      CL,04              ; CL = shift count
&0070:1502 D3EA             SHR      DX,CL              ; DX /= 16
&0070:1504 2BC2             SUB      AX,DX              ; subtract from total sectors
&0070:1506 268A0E0D00       MOV      CL,ES:[000D]       ; CL = sectors per cluster
&0070:150B 884D02           MOV      [DI+02],CL         ; (stash it)
&0070:150E 33D2             XOR      DX,DX              ; DX:AX = total sectors
&0070:1510 8AEE             MOV      CH,DH              ; CX = sectors per cluster
&0070:1512 F7F1             DIV      CX                 ; AX = number of whole clusters
&0070:1514 3DF60F           CMP      AX,0FF6            ; is number of clusters < 4086? (technically, that should be 4085)
&0070:1517 7205             JC       151E               ; yes, so it's a FAT12 volume
&0070:1519 800ECC1040       OR       [10CC],40          ; no, so mark it as FAT16
&0070:151E EB43             JMP      1563               ; wrap up
&0070:1520 90               NOP     
;
; We arrive here if the OEM signature was ANYTHING other than "IBM  2.0".
;
; SI will point to a table of 8-byte entries.  There are only two sets of entries.
;
;   SI+0:   total sectors threshold (1 word)            7FA8    FFFF
;   SI+2:   sectors per cluster shift count (1 byte)    03      02
;   SI+3:   sectors per cluster byte count (1 byte)     08      04
;   SI+4:   root directory entries (1 word)             0200    0200
;   SI+6:   flags (eg, 0040h implies FAT16)             0000    0040
;
&0070:1521 BEF910           MOV      SI,10F9            ; SI -> threshold table
&0070:1524 3B04             CMP      AX,[SI]            ; AX <= sector threshold?
&0070:1526 7605             JBE      152D               ; yes
&0070:1528 83C608           ADD      SI,0008            ; no, advance to next entry
&0070:152B EBF7             JMP      1524               ; try again
&0070:152D 8A4C06           MOV      CL,[SI+06]         ; load flags
&0070:1530 080ECC10         OR       [10CC],CL          ; save in "drive flags"
&0070:1534 8B4C02           MOV      CX,[SI+02]         ; CX = sectors per cluster info
&0070:1537 8B5404           MOV      DX,[SI+04]         ; DX = root directory entries
&0070:153A 895506           MOV      [DI+06],DX         ; (stash DX: root directory entries)
&0070:153D 886D02           MOV      [DI+02],CH         ; (stash CH: sectors per cluster byte count)
&0070:1540 F606CC1040       TEST     [10CC],40          ; FAT16?
&0070:1545 7525             JNZ      156C               ; yes
;
; FAT12 "sectors per FAT" calculation is performed identically to DOS 2.00
; (see the code at 70:099C from DOS 2.00, above)
;
&0070:1547 33DB             XOR      BX,BX
&0070:1549 8ADD             MOV      BL,CH
&0070:154B 4B               DEC      BX
&0070:154C 03D8             ADD      BX,AX
&0070:154E D3EB             SHR      BX,CL
&0070:1550 43               INC      BX
&0070:1551 80E3FE           AND      BL,FE
&0070:1554 8BF3             MOV      SI,BX
&0070:1556 D1EB             SHR      BX,1
&0070:1558 03DE             ADD      BX,SI
&0070:155A 81C3FF01         ADD      BX,01FF
&0070:155E D0EF             SHR      BH,1
&0070:1560 887D0B           MOV      [DI+0B],BH

&0070:1563 8A1ECC10         MOV      BL,[10CC]
&0070:1567 885D13           MOV      [DI+13],BL
&0070:156A F8               CLC     
&0070:156B C3               RET     
;
; FAT16 calculations (with some duplication of the logic at 70:1500):
;
&0070:156C B104             MOV      CL,04              ; CL = shift count
&0070:156E D3EA             SHR      DX,CL              ; DX /= 16
&0070:1570 2BC2             SUB      AX,DX              ; subtract from total sectors
&0070:1572 48               DEC      AX                 ; subtract 1 (assumes reserved sectors == 1?)
&0070:1573 B302             MOV      BL,02
&0070:1575 8A7D02           MOV      BH,[DI+02]         ; BX = sectors per cluster * 256 + 2
&0070:1578 33D2             XOR      DX,DX
&0070:157A 03C3             ADD      AX,BX              
&0070:157C 83D200           ADC      DX,0000            ; DX:AX = sector count + BX
&0070:157F 2D0100           SUB      AX,0001            
&0070:1582 83DA00           SBB      DX,0000            ; DX:AX = sector count + BX - 1
&0070:1585 F7F3             DIV      BX                 ; AX = (sector count + BX - 1) / BX
&0070:1587 89450B           MOV      [DI+0B],AX
&0070:158A EBD7             JMP      1563

PC DOS 3.00 introduces the same “sectors per FAT” calculation described in the FAT: General Overview of On-Disk Format for FAT16:

RootDirSectors = ((BPB_RootEntCnt * 32) + (BPB_BytsPerSec – 1)) / BPB_BytsPerSec;
TmpVal1 = DskSize – (BPB_ResvdSecCnt + RootDirSectors);
TmpVal2 = (256 * BPB_SecPerClus) + BPB_NumFATs;
FATSz = (TMPVal1 + (TmpVal2 – 1)) / TmpVal2;

The document goes on to say:

Do not spend too much time trying to figure out why this math works. The basis for the computation is complicated; the important point is that this is how Microsoft operating systems do it, and it works. Note, however, that this math does not work perfectly. It will occasionally set a FATSz that is up to 2 sectors too large for FAT16, and occasionally up to 8 sectors too large for FAT32. It will never compute a FATSz value that is too small, however. Because it is OK to have a FATSz that is too large, at the expense of wasting a few sectors, the fact that this computation is surprisingly simple more than makes up for it being off in a safe way in some cases.

However, that formula is actually very similar to how DOS 2.00 calculated sectors per FAT for FAT12 volumes. The similarity is just obscured by how the formula assumes a sector size of 512 to arrive at the 256 multiplier, whereas it did not assume a sector size of 512 at the beginning of the formula (it used BPB_BytsPerSec instead).

Ultimately, “sectors per FAT” has to be derived from “total clusters” divided by “number of cluster entries that fit in one FAT sector” (and noting that there are 256 16-bit entries in one 512-byte sector). The only thing that’s “complicated” about the formula is the rationale for adding BPB_NumFATs (which is invariably 2) to the TmpVal2 divisor; it was probably added as a way of compensating for the FAT sectors themselves, since they are not represented in the total overall sectors in TmpVal1.

Final Thoughts

One final observation I’ll make about the FAT: General Overview of On-Disk Format is that, since it was written many years after the earliest versions of DOS supporting FAT12 and FAT16 hard disks were released, it tended to gloss over details that were probably considered irrelevant at that point.

The OEM signature field in the BPB is a good example. The document really only had this to say about it:

There are many misconceptions about this field. It is only a name string. Microsoft operating systems don’t pay any attention to this field. Some FAT drivers do. This is the reason that the indicated string, “MSWIN4.1”, is the recommended setting, because it is the setting least likely to cause compatibility problems. If you want to put something else in here, that is your option, but the result may be that some FAT drivers might not recognize the volume. Typically this is some indication of what system formatted the volume.

Unfortunately, rather than dispelling misconceptions, the document actually added to them, because as we saw above, beginning with DOS 3.00 and – as far as I know – continuing in every version of DOS since then, the OEM signature played a role, sometimes a vital role, in determining the format of the disk and whether the BPB would be used.

pc.js, and the diskinfo.js module in particular, works hard to make sure the custom disk images it builds will work with the selected version of DOS. But I’m sure there are still combinations of drive geometries, FAT sizes, cluster sizes, DOS versions – and OEM signatures – that I haven’t tested and will fail to boot. Hopefully the volumes themselves, at least, will always be valid.

Fortunately, pc.js makes it easy to debug those situations. Just add --halt to the pc.js command-line and you’ll be dropped into the PCjs debugger before the machine starts booting.

Have fun!

Building DOS-Compatible Hard Disks

Thu, 10 Aug 2023 00:00:00 +0000

Last month, I wrote about a new tool I’ve been working on. pc.js is a stripped-down version of the web-based PCjs emulator that runs console-based DOS programs from the command-line. Since then, I’ve added a few more features and improved its ability to construct and load hard disk images.

Before I get into the changes, I want to re-emphasize something I mentioned last time:

“Only text-based “standard I/O” DOS programs are usable in this environment….”

Does that restriction exclude lots of DOS software? Absolutely. Does that make the tool useless? Absolutely not. For starters, virtually all the utilities bundled with DOS itself run fine; with a few exceptions, like BASIC and FDISK, they are all console-based applications, and even FDISK is usable, as is BASIC as long as you stick to INPUT and PRINT statements as your “basic” means of input and output. There are also quite a few DOS compilers, assemblers, linkers, debuggers, etc, that work well, too. Those kinds of programs – and only those – are what this tool was designed for. The ability to create and load DOS disk images, copy and delete files, compile and link programs, and perform other command-line tasks, all from the comfort of your modern command-line, is what pc.js is all about.

Running Local Commands

Previously, I went over how pc.js can automatically build a hard disk image containing all the files and folders in your current directory and then execute a DOS command or program, such as DIR:

$ pc.js dir

If you want a small collection of DOS files to start with, pc.js can fetch those for you:

$ pc.js --commands
pc.js v3.00
Copyright © 2012-2026 Jeff Parsons <Jeff@pcjs.org>
Options: --commands
[Type help for list of commands, CTRL-C to terminate]
>> fetch https://harddisks.pcjs.org/pcx86/10mb/MSDOS330-C400.json disks/msdos
>> quit

This should create a folder named disks/msdos containing a variety of DOS utilities and programs, which you can then pass to pc.js, along with an initial DOS command:

$ pc.js disks/msdos dir
[Press CTRL-D to enter command mode]

 Volume in drive C is MSDOS      
 Directory of  C:\

AUTOEXEC BAT      190   7-26-23  10:36a
CONFIG   SYS       22   1-01-80  12:03a
DOS          <DIR>      7-26-23  10:05a
PUZZLED      <DIR>      7-26-23  10:05a
TMP          <DIR>      1-01-80  12:13a
TOOLS        <DIR>      7-26-23  10:05a
        6 File(s)   5820416 bytes free

Next, let’s look at pc.json5, the configuration file for pc.js:

{
  "defaults": {
    "type": "pcx86",
    "sys": "msdos",
    "ver": "3.30",
    "target": "10M",
    "maxfiles": 1024,
    "directory": ".",
    "machine": "compaq386.json",
    "state": "state386.json"
  },
  "apps": {
    "ls": {},
    "vi": {},
    ".edit": {
      "exec": "vi $*"
    }
  },
  "systems": {
    "msdos": {
      "vendor": "microsoft",
      "files": ["IO.SYS", "MSDOS.SYS", "COMMAND.COM"]
    },
    "pcdos": {
        "vendor": "ibm",
        "files": ["IBMBIO.COM", "IBMDOS.COM", "COMMAND.COM"]
    }
  }
}                                                                                                                                                           

The apps section defines a set of local commands you can invoke from the DOS prompt. One of those commands is vi. Let’s try it:

C:\>vi AUTOEXEC.BAT

This runs a hidden VI.COM DOS program that silently shuts down the pc.js virtual machine, executes vi with the name of the AUTOEXEC.BAT file in your local directory, and when you save and quit vi, the virtual machine’s hard disk will be automatically rebuilt with any changes found in your local directory, the virtual machine will be restarted, and you should be back at the C:\> prompt within a few seconds.

You can add or remove programs from the apps section, and the next time you run pc.js, it will automatically create matching hidden .COM files in the root of the virtual hard disk. Make sure you stick to app names that are 8 characters or less; you can use the exec property to map a short filename to a longer or different local filename (see the edit example).

Aside from the commands listed in the apps section, two other programs are always included on the virtual hard disk: LOAD.COM, which makes it easy to load PCjs diskette images into drive A: or B:, and QUIT.COM, which shuts down the machine and returns to your local prompt (alternatively, you can press CTRL-D and type quit).

See Loading Diskettes from the DOS Prompt for more information and examples of the LOAD command (the internal LOAD command operates the same as the external LOAD.COM program).

Building Hard Disk Images

You may have noticed the defaults section in the pc.json5 configuration file:

  "defaults": {
    "type": "pcx86",
    "sys": "msdos",
    "ver": "3.30",
    "target": "10M",
    "maxfiles": 1024,
    "directory": ".",
    "machine": "compaq386.json",
    "state": "state386.json"
  }

These settings control what happens whenever pc.js builds (or rebuilds) a hard disk image from a specified folder. First and foremost, pc.js wants to create a bootable hard disk image, so it fetches the corresponding system diskette image from PCjs (eg, MSDOS330-DISK1), extracts the boot sector and system files (ie, IO.SYS and MSDOS.SYS) from the diskette, and then based on target, maxfiles, and other settings, it builds a hard disk image, which is stored in the PCjs /tools/pc/disks folder by default.

To change those defaults, you can either edit pc.json5 or pass command-line overrides; for example:

$ cd disks/msdos
$ pc.js ibm5170 --target=20M --fat=12 --maxfiles=2048 dir

This changes the default machine from a compaq386 to an ibm5170, sets the target drive size to 20Mb, forces the default FAT size to 12-bit (which would otherwise be 16-bit for a 20Mb disk), and allows up to 2048 local files to be included in the disk image.

You can also use --drivetype for even more control of the virtual hard disk image, but make sure the values you specify are valid for the machine being used. By default, pc.js loads a compaq386 machine, which also uses a saved machine state (state386.json) that bypasses the system startup tests and floppy drive checks, so that it can start booting from the virtual hard disk immediately. But the COMPAQ DeskPro 386 has a drive type table in ROM that differs significantly from the drive types defined by the IBM PC AT, so if you’re using an AT-specific drive type (eg, --drivetype=AT:6), then you should also specify an IBM 5170 machine configuration. An ibm5170.xml file is included in the pc.js folder to make this easier:

$ pc.js ibm5170 --drivetype=AT:6 dir

Some Caveats Regarding Disk Formats

With great disk-creating power comes great responsibility – or at least some basic knowledge of the limitations of various versions of DOS. For example, if you want to build a disk that uses a 16-bit FAT (perhaps because you want a smaller cluster size), then you must also build it with PC DOS or MS-DOS 3.0 or higher, since version 2.x only understood disks using a 12-bit FAT.

You can override the sys and ver defaults with command-line options --sys (short for --system) and --ver (short for --version); eg:

$ pc.js --sys=pcdos --ver=3.00 dir

Stick with DOS versions 2.x or 3.x for now. Support for other versions hasn’t been tested yet.

pc.js also tries to detect and fix certain broken combinations. For example, when I first tried to construct a 10Mb disk image with a 16-bit FAT running MS-DOS 3.30:

$ pc.js --target=10M --fat=16 dir

it failed to boot for several reasons.

The first problem was one described in this OS/2 Museum blog post from 2011: DOS 2.x and 3.x boot sectors read IO.SYS/IBMBIO.COM a track at a time, and if the final sector(s) of IO.SYS/IBMBIO.COM are located near the beginning of a track instead of the end of that track, the boot sector might read too much data and trash itself. This problem cropped up more often on disks with large tracks, but it could definitely also occur on disks with only 17 sectors/track. And even though I was using MS-DOS 3.30, which contained a fix, that fix was only present in the FORMAT.COM and SYS.COM utilities, not in the diskettes’ actual boot sector–which is what pc.js relies on.

pc.js now works around this bug by carefully adjusting the start of the partition, pushing the final sectors of IO.SYS to the end of a track.

However, that wasn’t the end of the story. A second problem occurs when IO.SYS/IBMBIO.COM examines the Master Boot Record (MBR) and DOS boot sector. DOS versions 3.10 and higher honor the MBR partition type and boot sector BPB values only if the OEM signature in the BPB contains the string “3.1” or greater. Otherwise, they fall back to the assumption that any disk with only 32680 (0x7FA8) or fewer sectors must be using a 12-bit FAT, 4K clusters, 512 directory entries, etc.

So, pc.js now ensures that any disk using a 16-bit FAT also contains an “IBM 3.1” OEM signature in its boot sector.

Finally, while testing pc.js with COMPAQ DOS 3.31, I discovered yet another problem. During testing, I forced the creation of a 16-bit FAT with 16K clusters:

pc.js --fat:16:16384 --sys=compaq:3.31g --halt

and discovered that COMPAQ DOS 3.31 crashes in a manner reminiscent of the earlier boot sector bug. In this case, after the boot sector carefully reads IBMBIO.COM one sector at a time (instead of one track a time), IBMBIO.COM then reads the entire FAT into memory (starting at 0:8000h), and then for reasons unknown, re-reads the final clusters of itself into memory again.

Note that IBMBIO.COM must fit completely between 0:0700h (its starting address) and 0:7B00h (where the system stack resides at this point). This is a 29K region, and IBMBIO.COM fits comfortably within that region. However, because the code that is re-reading IBMBIO.COM is reading whole clusters, when it reads the final cluster, it reads many more sectors than IBMBIO.COM actually uses, overrunning the region and trashing the stack.

The crash is ironic, because it’s identical to the boot sector crash that was finally fixed in this same release, except that instead of trashing itself with an entire (partially used) track, the code trashes itself with an entire (partially used) cluster.

Running DOS Software from the Command-Line

Sat, 15 Jul 2023 10:00:00 +0000

Recently, I’ve been working on a command-line utility that uses PCjs machines to run DOS software on modern operating systems, and it’s called, aptly enough, pc.js.

Let’s run through a few examples. All you need to get started is:

Install Node and NPM
Clone the pcjs repository (eg, git clone https://github.com/jeffpar/pcjs.git)
CD into pcjs and run npm install

For the examples below, I’m using Ubuntu Linux (hence the $ prompt), but I’ve also tested pc.js on macOS and Windows. If you run into issues, take a look at the pc.js page on the PCjs website.

I also recommend adding the “pcjs/tools/pc” and “pcjs/tools/diskimage” directories to your PATH, so that you can run pc.js and diskimage.js from any location. Alternatively, you can always use relative paths, like I’ve used in the examples.

The first example uses an original IBM PC (Model 5150), which didn’t support hard disks, and since we’ve also disabled booting from a floppy with --boot=none, all we can do is run some BASIC commands from the machine’s built-in BASIC interpreter:

$ cd tools/pc
$ pc.js ibm5150 --boot=none
Press CTRL-D to enter command mode, CTRL-C to terminate pc.js

1LIST   2RUN←   3LOAD"  4SAVE"  5CONT←  6,"LPT1 7TRON←  8TROFF← 9KEY    0SCREEN 
The IBM Personal Computer Basic 
Version C1.00 Copyright IBM Corp 1981 
61404 Bytes free
Ok 
print 2+2
4 
Ok 
10 for i=1 to 10:print "hello world";i:next i
list
10 FOR I=1 TO 10:PRINT "hello world";I:NEXT I                                   
Ok 
run
hello world 1 
hello world 2 
hello world 3 
hello world 4 
hello world 5 
hello world 6 
hello world 7 
hello world 8 
hello world 9 
hello world 10 
Ok 

So what just happened? BASICally, pc.js started an IBM PC Model 5150 with ROM BASIC, routing all text output to your terminal window and converting all text input into IBM PC keyboard presses, providing a reasonably seamless experience. That first line of output:

1LIST   2RUN←   3LOAD"  4SAVE"  5CONT←  6,"LPT1 7TRON←  8TROFF← 9KEY    0SCREEN 

is a list of supported function keys that would normally appear on the bottom (25th) row of an IBM PC monitor, but pc.js makes no attempt to render characters at specific screen locations – it simply outputs characters in the same order that the machine displays them.

As for the Press CTRL-D to enter command mode message at the beginning, pc.js is just letting you know that CTRL-D will allow you to stop the machine and enter what it calls “command mode”. If the machine also includes the PCjs debugger, command mode gives you access to all PCjs debugger commands, too.

From command mode, you can also press CTRL-C to terminate pc.js (or use the “quit” command). If you’re not in command mode, then CTRL-C just does whatever it’s supposed to do inside the machine. To exit command mode and continue running the machine, use the “g” (go) command.

Getting back to the first example above, let’s press CTRL-D for the pc.js command mode prompt, and then use the quit command to get back to the operating system prompt.

stopped (1027856675 cycles, 215793 ms, 4763160 hz)
AX=0000 BX=003A CX=0008 DX=008A SP=F9E8 BP=00A0 SI=0074 DI=0075 
SS=0060 DS=0040 ES=0060 PS=F046 V0 D0 I0 T0 S0 Z1 A0 P1 C0 
&F000:E850 74F3             JZ       E845 (romBIOS+0x0845)
>> help
internal commands:

abort   terminate without saving
build   build disk for specified drive type
exec    execute a local command
fetch   read disk image and extract to directory
load    load drive with specified diskette
save    save disk to directory or as disk image
select  select a new machine (eg, ibm5170)
start   start new machine
stop    stop current machine (does not save)
quit    save all changed files and terminate

type "?" for a list of debugger commands (eg, "g" to continue running)
>> quit
$

Working With Files

Now let’s dive into a much more interesting example. Imagine we have a small collection of DOS files and programs. There’s a PCjs hard disk image we can use for this demonstration, so we’ll start by running pc.js in interactive mode (--commands) and then use the fetch, build and start commands to extract all the files from that hard disk image, build a local hard disk image from those files, and then boot from that disk image using our default machine (a COMPAQ DeskPro 386):

$ pc.js --commands
pc.js v3.00
Copyright © 2012-2026 Jeff Parsons <Jeff@pcjs.org>
Options: --commands
[Type help for list of commands, CTRL-C to terminate]
>> fetch https://harddisks.pcjs.org/pcx86/10mb/MSDOS330-C400.json disks/msdos
>> build disks/msdos chkdsk
reading files: /Users/jeff/Sites/pcjs/tools/pc/disks/msdos/
building drive: /Users/jeff/Sites/pcjs/tools/pc/disks/msdos.json
>> start
loading machine: compaq386.json
>> [Press CTRL-D to enter command mode]
Volume MSDOS       created Jun 26, 2023 10:05a

 10588160 bytes total disk space
   106496 bytes in 9 hidden files
    86016 bytes in 21 directories
  4575232 bytes in 252 user files
  5820416 bytes available on disk

   655360 bytes total memory
   586256 bytes free

To run a program from the disks/msdos folder, such as the DOS CHKDSK utility, just run pc.js with name of the program, including any arguments it might need:

$ pc.js disks/msdos chkdsk
[Press CTRL-D to enter command mode]
Volume MSDOS       created Jun 26, 2023 10:15a

 10588160 bytes total disk space
   106496 bytes in 9 hidden files
    86016 bytes in 21 directories
  4575232 bytes in 252 user files
  5820416 bytes available on disk

   655360 bytes total memory
   586256 bytes free

If the DOS command you want to run includes wildcards (eg, DIR *.*), put it in quotes to prevent your shell from expanding them:

$ pc.js disks/msdos "dir *.*"
[Press CTRL-D to enter command mode]

 Volume in drive C is MSDOS      
 Directory of  C:\

AUTOEXEC BAT      194   6-26-23  10:18a
CONFIG   SYS       22   1-01-80  12:03a
DOS          <DIR>      6-26-23  10:05a
PUZZLED      <DIR>      6-26-23  10:05a
TMP          <DIR>      1-01-80  12:13a
TOOLS        <DIR>      6-26-23  10:05a
        6 File(s)   5820416 bytes free

This collection of files also includes a Microsoft C Compiler, so we can try compiling and running some C demo programs:

C:\>cd tools

C:\TOOLS>dir

Volume in drive C is MSDOS      
Directory of  C:\TOOLS

.            <DIR>      7-15-23   9:23a
..           <DIR>      7-15-23   9:23a
BIN          <DIR>      7-15-23   9:23a
BINB         <DIR>      1-01-80  12:11a
C4BIN        <DIR>      7-15-23   9:23a
C4CV         <DIR>      7-15-23   9:23a
C4DEMO       <DIR>      7-15-23   9:23a
C4INC        <DIR>      7-15-23   9:23a
C4LIB        <DIR>      7-15-23   9:23a
C4START      <DIR>      7-15-23   9:23a
C4WIN        <DIR>      7-15-23   9:23a
MASM4        <DIR>      7-15-23   9:23a
TOOLS    DIS      944   9-27-86  11:33a
TOOLS    INI     2725   1-01-80  12:06a
Z        TXT    72235  11-05-86  10:53a
    15 File(s)   6086656 bytes free

C:\TOOLS>cd c4demo

C:\TOOLS\C4DEMO>dir

Volume in drive C is MSDOS      
Directory of  C:\TOOLS\C4DEMO

.            <DIR>      7-15-23   9:23a
..           <DIR>      7-15-23   9:23a
DEMO     C        419   6-27-86   4:00a
SIEVE    C        788   6-27-86   4:00a
        4 File(s)   6086656 bytes free

C:\TOOLS\C4DEMO>cl demo.c
Microsoft (R) C Compiler  Version 4.00
Copyright (C) Microsoft Corp 1984, 1985, 1986.  All rights reserved.

demo.c
Microsoft (R) Overlay Linker  Version 3.51
Copyright (C) Microsoft Corp 1983, 1984, 1985, 1986.  All rights reserved.

Object Modules [.OBJ]: DEMO.OBJ 
Run File [DEMO.EXE]: DEMO.EXE/NOI
List File [NUL.MAP]: NUL
Libraries [.LIB]: ;

C:\TOOLS\C4DEMO>demo
C:\TOOLS\C4DEMO\DEMO.EXE
COMSPEC=C:\COMMAND.COM
PROMPT=$P$G
PATH=C:\;C:\TOOLS\C4BIN;C:\TOOLS\MASM4;C:\TOOLS\BIN;C:\TOOLS\BINB;C:\DOS
INCLUDE=C:\TOOLS\C4INC
LIB=C:\TOOLS\C4LIB
TMP=C:\TMP
USER=C:\TOOLS

C:\TOOLS\C4DEMO>cl sieve.c
Microsoft (R) C Compiler  Version 4.00
Copyright (C) Microsoft Corp 1984, 1985, 1986.  All rights reserved.

sieve.c
Microsoft (R) Overlay Linker  Version 3.51
Copyright (C) Microsoft Corp 1983, 1984, 1985, 1986.  All rights reserved.

Object Modules [.OBJ]: SIEVE.OBJ 
Run File [SIEVE.EXE]: SIEVE.EXE/NOI
List File [NUL.MAP]: NUL
Libraries [.LIB]: ;

C:\TOOLS\C4DEMO>sieve
150 iterations: 1027 primes

C:\TOOLS\C4DEMO>dir

Volume in drive C is MSDOS      
Directory of  C:\TOOLS\C4DEMO

.            <DIR>      7-15-23   9:23a
..           <DIR>      7-15-23   9:23a
DEMO     C        419   6-27-86   4:00a
SIEVE    C        788   6-27-86   4:00a
DEMO     OBJ      391   7-15-23   9:50a
DEMO     EXE     6402   7-15-23   9:50a
SIEVE    OBJ      494   7-15-23   9:50a
SIEVE    EXE    14662   7-15-23   9:50a
        8 File(s)   6053888 bytes free

C:\TOOLS\C4DEMO>quit
$

That last command, quit, runs a special program that pc.js automatically includes with the machine, to gracefully return to your own operating system.

And, if you take a peek inside the folder that corresponds to C:\TOOLS\C4DEMO, you’ll see that all the files created by the Microsoft C Compiler, such as DEMO.EXE and SIEVE.EXE have been preserved:

$ ls -l TOOLS/C4DEMO
total 40
-rw-rw-r-- 1    419 Jun 27  1986 DEMO.C
-rw-rw-r-- 1   6402 Jul 15 09:50 DEMO.EXE
-rw-rw-r-- 1    391 Jul 15 09:50 DEMO.OBJ
-rw-rw-r-- 1    788 Jun 27  1986 SIEVE.C
-rw-rw-r-- 1  14662 Jul 15 09:50 SIEVE.EXE
-rw-rw-r-- 1    494 Jul 15 09:50 SIEVE.OBJ

Whenever you run pc.js with a DOS command or program name, it automatically builds a 10Mb hard disk image containing all the files and folder from your current directory, and runs that command or program. And whenever you terminate pc.js, it automatically creates/deletes/updates any files in your current directory that were modified on the 10Mb hard disk.

Loading Diskettes

pc.js includes another special program with the machine, load, which makes it easy for you to load any diskette image from the PCjs diskette library into your machine. The syntax of the load command is:

load [drive] [search options]

Let’s say we want to load “PC-SIG Library Disk #1234” into the machine’s A: drive. Start pc.js with any DOS command to automatically build and start a machine (I used the DOS ver command this time) and then type load a: pc-sig 1234 to load the matching diskette into drive A:

$ pc.js disks/msdos ver
[Press CTRL-D to enter command mode]

MS-DOS Version 3.30    

C:\>load a: pc-sig 1234
loading "PC-SIG Library Disk #1234" in drive A:

C:\>dir a:

Volume in drive A has no label
Directory of  A:\

CHINA    HTX     8561   7-30-89   1:00p
CHINAVOC HTX     2927   7-17-88  12:05p
FILE1234 TXT     2480  11-30-89   4:19p
FIRST    HTX      405   9-16-89   2:39a
GO       BAT       15   9-17-89  11:34a
GO       HTX      511   9-17-89  11:33a
HELLO    EXE     8949   1-23-88  12:18p
HYTDOC   EXE    35282  10-01-89  12:59p
HYTDOC   HTF    35245  10-01-89  12:59p
HYTDOC   HTX    34936   9-17-89  11:18a
HYTEST   EXE    33528  10-01-89  12:58p
HYTEXT   EXE    42172  10-01-89   1:32p
HYTFAST  EXE    15753  10-01-89  12:57p
LOG      COM    10894   3-05-89  12:05p
LOG      DOC      920  11-03-88   5:06p
MSDOS    HTX    16129   6-17-88   7:55p
PLANETS  HTS     6248   3-31-89   8:10p
README           6596   9-28-89   8:55p
VERSION          2246   9-16-89  11:15p
    19 File(s)     48128 bytes free

If your search criteria matches more than one diskette in the library, a numbered list of matches is displayed, and then you can load the desired diskette by number:

C:\>load a: pc-sig #123
1: PC-SIG Library Disk #1230
2: PC-SIG Library Disk #1231
3: PC-SIG Library Disk #1232
4: PC-SIG Library Disk #1233
5: PC-SIG Library Disk #1234
6: PC-SIG Library Disk #1235
7: PC-SIG Library Disk #1236
8: PC-SIG Library Disk #1237
9: PC-SIG Library Disk #1238
10: PC-SIG Library Disk #1239
enter "load a: #" to load diskette by number

C:\>load a: 6
loading "PC-SIG Library Disk #1235" in drive A:

C:\>dir a:

Volume in drive A has no label
Directory of  A:\

EDBEGIN  HLP    24539   6-19-89  12:04p
EDQUICK  HLP    37793   6-19-89  12:04p
FILEMAN  COM      932   4-01-86  11:24p
GETYN    COM      806   9-25-89   5:18p
GO       BAT       12   5-18-86   8:32p
MANUAL1  CRN    30164  11-07-88  10:49p
MANUAL2  CRN   122155  11-07-88  10:50p
PRINTMAN COM      913  10-26-88   6:23a
QUICK-OR DER     1021   5-04-89   4:23p
READ     ME      1001   9-29-89  12:48p
REFENCE  DIR     1249   9-29-89  12:50p
STORY            1148  12-24-86  11:11a
TYPEMAN  COM      947  10-28-88   3:38a
WORDS    EXE    16536  10-02-86   9:41p
WORDS    MAS   110428   9-19-89   6:41p
WORDS    NUL       12  10-26-88  11:10a
WORKUTIL BAT     5086   9-25-89   4:30p
    17 File(s)      1024 bytes free

You can also search for files by filename. For example, if you want to find and load a diskette with a program containing ARC in the name, use the --file search option. You can even use regular expressions, but you will need to quote them if you use any characters (such as |) that are also parsed by the DOS command interpreter:

C:\>load a: --file="arc\.(com|exe)"
ARC.EXE         32128 1979-11-30  "PC-SIG Library Disk #4198"
ARC.EXE         29824 1985-08-22  "PC-SIG Library Disk #0539"
ARC.EXE         32051 1986-01-31  "PC-SIG Library Disk #0976"
ARC.EXE         32429 1986-02-05  "PC-SIG Library Disk #0685"
ARC.EXE         32256 1986-02-21  "PC-SIG Library Disk #0612"
ARC.EXE         32181 1986-03-05  "PC-SIG Library Disk #0417"
ARC.EXE         32512 1986-04-08  "PC-SIG Library Disk #0879"
ARC.EXE         32384 1986-06-15  "PC-SIG Library Disk #0666"
CONVARC.EXE      5056 1989-07-24  "PC-SIG Library Disk #1571"
DARC.EXE        34429 1990-06-09  "PC-SIG Library Disk #1861"
DEARC.COM       10240 1986-12-28  "PC-SIG Library Disk #0148"
EIGHTARC.COM    51968 1989-06-21  "PC-SIG Library Disk #1574"
ELECARC.EXE     97669 1990-05-15  "PC-SIG Library Disk #2219"
EPARC.COM       26316 1990-01-19  "PC-SIG Library Disk #1082"
HELPARC.EXE    267704 1991-08-05  "Norton Utilities 6.01 (Utility 4)"
ICONARC.EXE     16944 1991-08-05  "Norton Utilities 6.01 (Install)"
LHARC.EXE       27498 1989-03-04  "PC-SIG Library Disk #1550"
LHARC.EXE       30470 1989-05-04  "PC-SIG Library Disk #2018"
LHARC.EXE       31256 1989-05-31  "PC-SIG Library Disk #1948"
LHARC.EXE       30912 1990-03-28  "PC-SIG Library Disk #1927"
LHARC.EXE       20874 1990-06-15  "PC-SIG Library Disk #1145"
LHARC.EXE       30440 1990-07-28  "PC-SIG Library Disk #2729"
LHARC.EXE       20874 1990-08-07  "PC-SIG Library Disk #2322"
LHARC.EXE       20475 1990-08-08  "PC-SIG Library Disk #2597"
NDOSARC.EXE     39190 1991-08-05  "Norton Utilities 6.01 (Utility 5)"
OBJUNARC.EXE   125440 1993-08-13  "OBJASM 2.0 (Bin)"
PASARC.EXE     102889 1990-05-10  "PC-SIG Library Disk #2221"
PGMSARC.EXE    120567 1990-07-24  "PC-SIG Library Disk #1481"
PKARC.COM       16440 1986-10-23  "PC-SIG Library Disk #0386"
PKARC.COM       17456 1986-12-15  "PC-SIG Library Disk #1138"
PKXARC.COM       9984 1986-09-12  "PC-SIG Library Disk #0599"
PKXARC.COM      10318 1986-10-23  "PC-SIG Library Disk #0386"
PKXARC.COM      11482 1986-12-15  "PC-SIG Library Disk #0651"
PKXARC.COM      12242 1987-03-01  "PC-SIG Library Disk #1080"
PKXARC.COM      12242 1987-04-27  "PC-SIG Library Disk #1564"
PKXARC.COM      10368 1987-08-25  "PC-SIG Library Disk #2388"
PKXARC.COM      11648 1987-10-08  "PC-SIG Library Disk #1138"
PKXARC.COM      12288 1988-02-19  "PC-SIG Library Disk #1063"
PKXARC.COM       9296 1990-03-26  "PC-SIG Library Disk #2822"
PKXARC.EXE      15126 1988-06-01  "PC-SIG Library Disk #1206"
POSIARC.EXE    133618 1990-05-15  "PC-SIG Library Disk #2219"
QUOTARC.EXE    226289 1990-01-26  "PC-SIG Library Disk #1575"
RINGARC.EXE     84235 1989-12-29  "PC-SIG Library Disk #1293"
SANDARC.EXE    188632 1992-12-02  "PC-SIG Library Disk #3555"
SHZIPARC.EXE   256492 1990-12-26  "PC-SIG Library Disk #2614"
SMITHARC.EXE   305210 1992-06-28  "PC-SIG Library Disk #3125"
SPORTARC.EXE    36592 1992-09-30  "PC-SIG Library Disk #3454"
TD1ARC.EXE     247060 1989-12-31  "PC-SIG Library Disk #1353"
UNARC.COM       12242 1987-04-27  "PC-SIG Library Disk #3008"
XARC.COM        12242 1987-04-27  "PC-SIG Library Disk #2096"
XARC.COM        11482 1987-06-17  "PC-SIG Library Disk #3494"
XXSRARC.EXE    275219 1992-09-18  "PC-SIG Library Disk #3222"
enter "load a: #" to load diskette by number

To help you zero in on the particular ARC program you’re interested in, pc.js initially lists only unique instances of each file. Let’s say you’re only interested in files named ARC.EXE, and you want to load a diskette with the version of ARC.EXE dated 1985-08-22, so you type load a: 2:

C:\>load a: 2
  1: ARC.EXE         29824 1985-08-22  "PC-SIG Library Disk #0539"
  2: ARC.EXE         29824 1985-08-22  "PC-SIG Library Disk #0420"
  3: ARC.EXE         29824 1985-08-22  "PC-SIG Library Disk #0568"
enter "load a: #" to load diskette by number
multiple disks with identical file (use "load a: 1" to load original selection)

At this point, pc.js shows you all the other disks (if any) with the same exact file. The other files may not have the same date or even the same name, but they will all have the same contents. Your original selection is always listed first. In this example, we’re going to load the second disk, named “PC-SIG Library Disk #0420”:

C:\>load a: 2
loading "PC-SIG Library Disk #0420" in drive A:

C:\>dir a:

Volume in drive A has no label
Directory of  A:\

BACKSTAT EXE    13312   1-17-85   2:20p
GCOPY2   EXE    14592   3-15-85   3:18p
GCOPY2   TXT     2048   3-15-85   3:18p
L6       COM     3072   4-09-85   9:41a
LC       COM     1280  12-07-84   1:10p
LF       COM      512   6-08-84   3:20p
LQTYPE   COM    12160   4-01-85  11:14a
UNDEL    COM     2176   3-19-85   6:57a
UNSQ     COM     8064   3-17-85   2:53p
FILTERS  LBR    41600   4-04-85  10:16a
FILTERS  TXT      507   4-04-85   6:03p
VIEWDISK EXE    16384   3-15-85   8:36a
VIEWDISK DOC     4736   3-15-85   8:38a
COPYPC   COM     1792   4-25-85   1:52p
COPYPC   DOC     1920   4-25-85   1:52p
SORT-IT  COM    17280   4-03-85  10:17a
SORT-IT  DOC     1024   4-03-85  10:18a
NIB      EXE    48412   5-02-85   4:42p
LOCK     COM      384   8-22-85  12:51a
UNLOCK   COM      384   8-22-85  12:51a
UN-LOCK  DOC     2432   8-22-85  12:52a
ARC      EXE    29824   8-22-85  12:50a
ARC      DOC    10880   5-06-85  10:14a
FCOMPARE EXE    12288   5-02-85  12:03a
FCOMPARE C      13056   5-02-85  12:03a
FCOMPARE DOC     2304   5-02-85  12:03a
SEARCH   COM      640   5-08-85   6:58p
SEARCH   DOC     2048   5-08-85   6:58p
READONLY COM      128   6-03-85  10:15p
READONLY DOC      256   6-03-85  10:15p
READWRIT COM      128   6-03-85  10:15p
READWRIT DOC      128   6-03-85  10:15p
DISKUNSQ COM     3712   6-04-85  12:19p
DISKSQ   COM     3584   6-04-85  12:20p
TREED    COM     1920   5-10-85   9:37p
TCOUNT   COM    17273   7-29-85   9:30a
TCOUNT   DOC     7168   7-28-85   8:05a
FILES420 TXT     2088   4-12-86   5:50p
LU       DOC     6144   3-25-84   1:50a
LU       EXE    22528   3-25-84   1:48a
    40 File(s)     16384 bytes free

Any files you’re interested in can be copied to the machine’s C: drive, and when you type quit, those files should be automatically transferred to your current directory.

More To Come

There’s a lot more to cover with the new pc.js utility, which is still a “work-in-progress”, but hopefully this is enough to get the ball rolling.

Only text-based “standard I/O” DOS programs are usable in this environment, so if you run a program that switches to graphics mode or writes directly to video memory, don’t expect to see anything.

There are currently no options to change the default drive type (10Mb) but it is possible to specify alternate machine configurations and alternate operating systems to install on the drive. Run pc.js --help from the command-line for some quick guidance, and check the PC.js page for more detailed information – both will be updated as the utility evolves.

Old IBM PC BASIC Programs

Fri, 05 May 2023 10:00:00 +0000

BASIC shipped with every IBM PC, both in the machine’s ROM and on DOS diskettes, making it the easiest (and cheapest) way to create programs that could run on every other IBM PC in the world. So it’s no surprise that a lot of BASIC software was created and distributed throughout the 1980s.

I recently wrote some new libraries to help create an online version of the PC-SIG Diskette Library, a large collection of public domain software and shareware spanning thousands of diskettes, and since the collection contained a lot of BASIC programs, I thought I’d create a list of them (over 2500), complete with links.

So, here you go!

$$MENU.BAS (1985), $ENVED.BAS (1987), %-DIFF.BAS (1982), 0.BAS (1984), 1.BAS (1984), 10.BAS (1984), 1004-B.BAS (1984), 1005-A.BAS (1984), 1009-A.BAS (1984), 11.BAS (1984), 12.BAS (1984), 123DOC.BAS (1984), 123DOC.BAS (1985), 123RANGE.BAS (1983), 13.BAS (1984), 14.BAS (1984), 15.BAS (1984), 1500.BAS (1980), 15PUZZLE.BAS (1983), 16.BAS (1984), 17.BAS (1984), 2.BAS (1984), 20.BAS (1984), 21.BAS (1980), 23MATCH.BAS (1980), 2ERRORS.BAS (1992), 3-D-ROT.BAS (2008), 3.BAS (1984), 3002-A.BAS (1984), 3003-A.BAS (1984), 3006-A.BAS (1984), 3012-A.BAS (1984), 3014-A.BAS (1984), 3DTT.BAS (1980), 3PART.BAS (1987), 4.BAS (1984), 4028-A.BAS (1984), 4BARLINK.BAS (1984), 5.BAS (1984), 5006-A.BAS (1984), 6.BAS (1984), 7.BAS (1984), 7013-A.BAS (1984), 7037-A.BAS (1984), 7042-A.BAS (1984), 78INT.BAS (1983), 8.BAS (1984), 9.BAS (1984), A0.BAS (1980), A1.BAS (1983), A2.BAS (1983), A3.BAS (1983), A4.BAS (1983), ABC.BAS (1986), ABC.BAS (1987), ABC.BAS (1988), ABCONVRT.BAS (1980), ACATALOG.BAS (1983), ACCTREC.BAS (1985), ACEY-DUE.BAS (1979), ACEY.BAS (1985), ACRE.BAS (1986), ACRS.BAS (1983), ACRS.BAS (1984), ACRSCALC.BAS (1980), ACTDTL.BAS (1989), AD.BAS (1983), ADD-LF.BAS (1982), ADDCR.BAS (1982), ADDCRS.BAS (1982), ADDCRS.BAS (1982), ADDELETE.BAS (1984), ADDFILE.BAS (1982), ADDINFO.BAS (1988), ADDIR.BAS (1984), ADDMAIL.BAS (1982), ADDMEMB.BAS (1982), ADDR-PH.BAS (1982), ADDRBOOK.BAS (1985), ADDRESS.BAS (1980), ADDRESS.BAS (1984), ADDRFLCD.BAS (1982), ADEDIT.BAS (1984), ADFILES.BAS (1984), ADIABAT.BAS (1980), ADLIST.BAS (1980), ADMAIL.BAS (1984), ADMAIN.BAS (1980), ADNAME.BAS (1983), ADNOTE.BAS (1980), ADPRINT.BAS (1980), ADPRT.BAS (1984), ADPRTA.BAS (1980), ADPRTC.BAS (1980), ADREAD.BAS (1980), ADRODX.BAS (1984), ADSEARCH.BAS (1980), ADSORT.BAS (1984), ADSTART.BAS (1980), ADTRANS.BAS (1984), ADVANCED.BAS (1984), ADVEN1.BAS (1985), ADWP.BAS (1983), ADWS.BAS (1983), ADZIP.BAS (1980), AID.BAS (1984), AIRNAV.BAS (1985), AJETCRUZ.BAS (1983), AJETOFF.BAS (1983), ALGEBRA.BAS (1983), ALIEN.BAS (1980), ALIEN.BAS (1984), ALIGN.BAS (1983), ALPHA.BAS (1989), ALPHAHEX.BAS (1987), ALPHAMAR.BAS (1989), ALPHAPER.BAS (1989), AMORT.BAS (1985), AMORTIZE.BAS (1986), AMRTMENU.BAS (1985), AM_ED.BAS (1987), ANALOG.BAS (1982), ANALOG.BAS (1990), ANALOG2.BAS (1982), ANALOG3.BAS (1982), ANALOG4.BAS (1982), ANALOG5.BAS (1982), ANALOG6.BAS (1982), ANCESTOR.BAS (1989), ANCOV.BAS (1989), ANGS.BAS (1986), ANIM.BAS (1990), ANIMAL.BAS (1980), ANIMATE.BAS (1980), ANIMATE.BAS (1980), ANNUITY.BAS (1988), ANOV1.BAS (1989), ANOVA.BAS (1986), ANOVK.BAS (1990), ANOVR.BAS (1989), ANOVU.BAS (1989), ANSWERS.BAS (1989), ANT2.BAS (1984), ANTONYM.BAS (1982), ANTONYM2.BAS (1982), ANTONYMS.BAS (1980), ANVIL.BAS (1984), APL-QREF.BAS (1990), APL-QREF.BAS (1990), APLIB-H.BAS (1990), APPENDIX.BAS (1986), APPENDIX.BAS (1989), APPLECOM.BAS (1982), APPLECOM.BAS (1982), ARCHIE.BAS (1982), ARCTRIG.BAS (1985), AREACODE.BAS (1984), ARKTRAV.BAS (1982), ARROW.BAS (1980), ARTILL.BAS (1983), ASCFILTR.BAS (1982), ASCICHAR.BAS (1983), ASCII.BAS (1983), ASCII.BAS (1983), ASCTTY.BAS (1985), ASDA.BAS (1980), ASDADEL.BAS (1983), ASDARUN.BAS (1980), ASSEMBLY.BAS (1980), ASTEROID.BAS (1984), ASYN-PGM.BAS (1982), ATLAS.BAS (1980), ATLASARM.BAS (1980), ATMOS.BAS (1987), ATO.BAS (1984), ATTACK.BAS (1982), ATTRIB.BAS (1980), AUTHOR.BAS (1980), AUTHOR2.BAS (1980), AUTODIAL.BAS (1983), AUTOFILE.BAS (1983), AUTOFILE.BAS (1983), AUTOINST.BAS (1983), AUTOPEEK.BAS (1983), AUTOST.BAS (1983), AVERAGE.BAS (1983), AWARI.BAS (1980), AWARI.BAS (1980), B-SIMPLE.BAS (1982), B.BAS (1981), B1.BAS (1980), B1.BAS (1981), B10.BAS (1982), B11.BAS (1982), B12.BAS (1982), B13.BAS (1982), B14.BAS (1982), B15.BAS (1982), B16.BAS (1982), B17.BAS (1982), B18.BAS (1982), B19.BAS (1982), B2.BAS (1982), B20.BAS (1986), B3.BAS (1982), B4.BAS (1982), B5.BAS (1982), B6.BAS (1982), B7.BAS (1982), B8.BAS (1982), B9.BAS (1982), BACCRRT.BAS (1983), BACH.BAS (1983), BACH.BAS (1983), BACH2.BAS (1984), BACKGAM.BAS (1984), BACKUP.BAS (1982), BACKUP.BAS (1983), BAGPIPES.BAS (1982), BALANCE.BAS (1982), BALL.BAS (1980), BALL.BAS (1980), BALLOON.BAS (1985), BALREM.BAS (1986), BANDDEMO.BAS (1984), BANKER.BAS (1982), BANNER.BAS (1980), BANNER.BAS (1980), BANNER.BAS (1983), BAR3OF9.BAS (1990), BARCODE.BAS (1990), BARGRAPH.BAS (1979), BARIC.BAS (1980), BARL.BAS (1986), BARS.BAS (1980), BASBUG.BAS (1984), BASCONV.BAS (1983), BASEBALL.BAS (1983), BASEBALL.BAS (1983), BASECONV.BAS (1980), BASECONV.BAS (1983), BASHADAM.BAS (1980), BASIC.BAS (1980), BASIC.BAS (1980), BASICAID.BAS (1984), BASICDOS.BAS (1984), BASICPRT.BAS (1982), BASICREF.BAS (1980), BASKEYS.BAS (1983), BASLISTI.BAS (1987), BASMENU.BAS (1982), BASMENU.BAS (1982), BASPARAM.BAS (1985), BASSUB.BAS (1984), BASTAT2V.BAS (1980), BASTOD.BAS (1984), BASTODOS.BAS (1983), BASTODOS.BAS (1984), BASTOFOR.BAS (1983), BATMAN.BAS (1983), BAYES.BAS (1986), BBS-TALK.BAS (1984), BBSLOGO.BAS (1983), BEAR123.BAS (1986), BEAR123.BAS (1988), BEARABC.BAS (1986), BEARABC.BAS (1988), BESSELJN.BAS (1984), BESSELYN.BAS (1984), BESTCROP.BAS (1980), BESTCROP.BAS (1984), BESTLINE.BAS (1980), BFC.BAS (1988), BFP.BAS (1984), BIBLE.BAS (1982), BIGCALC.BAS (1985), BIGCHAR.BAS (1979), BIGTYPE.BAS (1983), BIGTYPE1.BAS (1982), BIHEX.BAS (1982), BIKEINFO.BAS (1989), BINOMIAL.BAS (1986), BIO.BAS (1980), BIO.BAS (1982), BIORYTHM.BAS (1983), BIORYTHM.BAS (1983), BIRD.BAS (1983), BIRDS.BAS (1982), BIRTHDAY.BAS (1983), BITSTRIP.BAS (1989), BKPG.BAS (1984), BKSPACE.BAS (1982), BLACK.BAS (1982), BLACK.BAS (1986), BLACKBOX.BAS (1980), BLACKBOX.BAS (1983), BLACKBOX.BAS (1984), BLACKJCK.BAS (1980), BLACKJCK.BAS (1982), BLASTER.BAS (1980), BLASTOFF.BAS (1982), BLCKJACK.BAS (1983), BLESS.BAS (1982), BLIMP.BAS (1982), BLKFRDY.BAS (1983), BLKFRI3.BAS (1980), BLKLETER.BAS (1982), BLOAD.BAS (1987), BLOAD.BAS (1990), BLOAD.BAS (1990), BLOB.BAS (1980), BLUEBERY.BAS (1987), BLUEMENU.BAS (1987), BLUESBOX.BAS (1983), BMENU.BAS (1982), BMENUD.BAS (1982), BNEST1.BAS (1989), BNEST2.BAS (1988), BNEST3.BAS (1988), BNEST4.BAS (1989), BOARD1.BAS (1988), BOARD2.BAS (1988), BOGGLE.BAS (1983), BOMB.BAS (1980), BOMB.BAS (1980), BOMB.BAS (1982), BOND.BAS (1982), BOOGERS!.BAS (1984), BOOKINV.BAS (1984), BOULDER.BAS (1989), BOUREE.BAS (1984), BOX.BAS (1983), BOXES-U.BAS (1990), BOXES-U.BAS (1990), BOXES.BAS (1985), BOXINBOX.BAS (1987), BOXINPUT.BAS (1987), BR.BAS (1989), BR2DIFFN.BAS (1980), BREAKOUT.BAS (1980), BREAKOUT.BAS (1982), BREAKOUT.BAS (1982), BRIEFLY.BAS (1984), BROWMAIL.BAS (1982), BS.BAS (1989), BSAVE.BAS (1987), BSR.BAS (1983), BTMENU.BAS (1980), BTMENU.BAS (1980), BTRIEV.BAS (1990), BTU.BAS (1986), BUBLSORT.BAS (1984), BUDGET.BAS (1983), BUILDML.BAS (1982), BUILFILE.BAS (1982), BUILGRAF.BAS (1982), BUILMEMB.BAS (1982), BULLSEYE.BAS (1981), BULLSEYE.BAS (1982), BUNNY.BAS (1986), BUNNY.BAS (1988), BUSCHECK.BAS (1987), BUSIN.BAS (1983), BUSPGM.BAS (1980), BUTTRFLY.BAS (1982), BWDEMOI.BAS (1988), BYE.BAS (1987), C.BAS (1981), CACHEJR.BAS (1986), CAL-YR.BAS (2099), CALC.BAS (1991), CALCULA.BAS (1984), CALENDAR.BAS (1983), CALENDAR.BAS (1983), CALEPSON.BAS (1983), CALLGRAF.BAS (1985), CALULATE.BAS (1987), CANDY.BAS (1985), CANNON.BAS (1982), CAPLOCK.BAS (1985), CAPTURE.BAS (1980), CARCOST.BAS (1984), CAS-REEL.BAS (1983), CASH.BAS (1984), CASHACC.BAS (1982), CASHREG.BAS (1984), CASTLE.BAS (1980), CASTLE.BAS (1982), CATCH88.BAS (1982), CAVEMAP1.BAS (1990), CBD.BAS (1985), CESMOUSE.BAS (1991), CFILE.BAS (1983), CFORM.BAS (1983), CFP.BAS (1984), CHAIRMAN.BAS (1980), CHAIRMAN.BAS (1980), CHANGE.BAS (1983), CHARDEFN.BAS (1984), CHARDISP.BAS (1982), CHARDISP.BAS (1983), CHARGEHI.BAS (1986), CHARMAP.BAS (1980), CHARS.BAS (1983), CHARS.BAS (1984), CHARS2.BAS (1982), CHASE.BAS (1980), CHECK.BAS (1985), CHECKCON.BAS (1982), CHECKERS.BAS (1980), CHECKING.BAS (1985), CHECKOUT.BAS (1982), CHECKOUT.BAS (1983), CHEKFORM.BAS (1987), CHEMQUES.BAS (1983), CHEMTEST.BAS (1983), CHESS.BAS (1980), CHESS.BAS (1983), CHESS1.BAS (1982), CHGMAIL.BAS (1982), CHICK.BAS (1985), CHIEF.BAS (1980), CHIRP.BAS (1982), CHISQDIS.BAS (1984), CHISQR.BAS (1986), CHKREG.BAS (1989), CHMOD.BAS (1984), CHOPIN1.BAS (1983), CHR$PRNT.BAS (1987), CHR-DEMO.BAS (1984), CHR-DEMO.BAS (1984), CHR-DEMO.BAS (1984), CHR.BAS (1982), CHRONSET.BAS (1982), CHRSET.BAS (1982), CHSONG.BAS (1982), CI1.BAS (1988), CI2.BAS (1988), CI3.BAS (1988), CIA.BAS (1980), CIA.BAS (1985), CIAGAME.BAS (1982), CICADA.BAS (1985), CINPUT.BAS (1980), CIPHER.BAS (1983), CIRCLE.BAS (1980), CIRCLES.BAS (1980), CIRCLOOP.BAS (1982), CIRMIL2.BAS (1986), CITOHSET.BAS (1982), CIVILWAR.BAS (1983), CIVILWAR.BAS (1985), CKNUM.BAS (1983), CLASROLL.BAS (1983), CLASSICS.BAS (1983), CLERK.BAS (1983), CLIMATES.BAS (1980), CLIMITS.BAS (1983), CLKMOD.BAS (1982), CLOCK.BAS (1980), CLOCK.BAS (1982), CLOCK.BAS (1985), CLOCK.BAS (1991), CLOCK.BAS (1990), CLOUD-9.BAS (1980), CM.BAS (1986), CM2.BAS (1986), CM3.BAS (1986), CNFG-SUB.BAS (1990), CNFG-VAR.BAS (1990), CNTRL-BR.BAS (1985), CNTRLBK.BAS (1983), COCOTRAN.BAS (1990), COFFEE.BAS (2025), COILINDU.BAS (1985), COLCONST.BAS (1990), COLLIDE.BAS (1983), COLOR.BAS (1980), COLOR.BAS (1982), COLOR.BAS (1983), COLOR.BAS (1984), COLORNUD.BAS (1988), COLORSET.BAS (1983), COLORSET.BAS (1990), COLRFILE.BAS (1982), COLRGRAF.BAS (1982), COLSLOT.BAS (1984), COLTOMON.BAS (1982), COM2ASM.BAS (1983), COMBAT.BAS (1985), COMBOT.BAS (1985), COMCHRON.BAS (1982), COMM.BAS (1983), COMP.BAS (1984), COMPACT.BAS (1985), COMPET.BAS (1989), COMPIL.BAS (1984), COMPOUND.BAS (1982), COMPOUND.BAS (1987), COMPRESS.BAS (1982), COMPRESS.BAS (1984), COMPUTER.BAS (1982), COMSEP.BAS (1985), CONCOL.BAS (2001), CONFIG.BAS (1984), CONFIG.BAS (1986), CONFIG.BAS (1990), CONTENTS.BAS (1983), CONTEST.BAS (1987), CONTROL.BAS (1982), CONTROL.BAS (1982), CONTY.BAS (1989), CONV.BAS (1982), CONV.BAS (1985), CONVERGE.BAS (1980), CONVERT.BAS (1983), CONVERT.BAS (1984), CONVERT.BAS (1985), CONVERT.BAS (1988), COPFILE.BAS (1982), COREFIX.BAS (1982), COREFIX.BAS (1984), COREL.BAS (1990), CORMT.BAS (1989), CORRELAT.BAS (1986), COUNTING.BAS (1980), COUNTING.BAS (1986), COVLTR.BAS (1988), COVSHT.BAS (1988), COWCRAB.BAS (1984), CPRINT.BAS (1982), CQSS.BAS (1986), CR.BAS (1982), CRAPS.BAS (1982), CRAPS.BAS (1985), CRASHER.BAS (1982), CRAZY8.BAS (1983), CRCROP.BAS (1984), CREAL.BAS (1980), CREATE.BAS (1982), CREATMAR.BAS (1989), CREATOR.BAS (1984), CREATOR.BAS (1983), CREATORD.BAS (1989), CREATPER.BAS (1989), CREDITCA.BAS (1986), CREDITPU.BAS (1986), CRETURN.BAS (1980), CRIB2.BAS (1984), CRIBBAGE.BAS (1980), CRIBBAGE.BAS (1983), CRITICAL.BAS (1982), CRL.BAS (1984), CRL.BAS (1984), CROSSBAS.BAS (1990), CROSSREF.BAS (1982), CRS.BAS (1984), CRYPT.BAS (1987), CRYPT.BAS (1987), CRYPTO.BAS (1987), CSCREEN.BAS (1980), CTEMP.BAS (1980), CTRANSFE.BAS (1983), CUBE.BAS (1980), CUBE.BAS (1982), CUBICFIT.BAS (1980), CUBICSPL.BAS (1980), CURVE.BAS (1980), CURVE.BAS (1985), CURVE2.BAS (1980), CURVE3.BAS (1980), CURVEFIT.BAS (1980), CURVEFIT.BAS (1989), CURVEGEN.BAS (1989), CURVEQB4.BAS (1989), CUSTOM.BAS (1983), CVTBIN.BAS (1984), CWRCV.BAS (1985), CYCLE.BAS (1983), D&CFORM.BAS (1987), DAILY.BAS (1989), DAILYODO.BAS (1986), DANCE.BAS (1983), DARTH.BAS (1988), DATA-ONE.BAS (1986), DATA1.BAS (1983), DATA2.BAS (1983), DATAFIX.BAS (1980), DATAPGM.BAS (1980), DATECALC.BAS (1984), DATEDIST.BAS (1986), DATESINM.BAS (1986), DATETIME.BAS (1983), DATFL.BAS (1989), DATNOIDS.BAS (1984), DAY.BAS (1986), DAYLOG.BAS (1982), DAYNUM.BAS (1985), DAYOFWEE.BAS (1986), DAYOFWK.BAS (1985), DAYS.BAS (1985), DB.BAS (1987), DBASECHG.BAS (1984), DBMENU.BAS (1982), DC-SORT.BAS (1983), DCATFILE.BAS (1982), DEBYESOL.BAS (1984), DECIDE.BAS (1982), DECIDE.BAS (1982), DECISION.BAS (1980), DECTOHEX.BAS (1980), DEFEND.BAS (1982), DEFINE.BAS (1983), DEFINE.BAS (1984), DEFKEY.BAS (1983), DEFRAG.BAS (1984), DEFRAG.BAS (1984), DEFSEG.BAS (1990), DELMAIL.BAS (1982), DEMO.BAS (1980), DEMO.BAS (1983), DEMO.BAS (1984), DEMO.BAS (1984), DEMO.BAS (1990), DEMO.BAS (1991), DEMO20.BAS (1987), DEMO3.BAS (1980), DEMOEX.BAS (1990), DEMOSET.BAS (1984), DEMOSUB.BAS (1985), DEMO_2.BAS (1990), DEPGROWS.BAS (1986), DEPREC.BAS (1982), DESCEND.BAS (1989), DESERT.BAS (1980), DESERT.BAS (1982), DESIGN.BAS (1982), DESIGNER.BAS (1993), DETAB.BAS (1984), DHDEMO.BAS (1983), DICE.BAS (1980), DIET.BAS (1984), DIFFCAP.BAS (1980), DIGIDRAW.BAS (1983), DIPOLE.BAS (1985), DIR.BAS (1983), DIR2.BAS (1983), DIR201.BAS (1984), DIR4.BAS (1985), DIRDEM.BAS (1984), DIRECT.BAS (1984), DIRECTOR.BAS (1985), DIRECTOR.BAS (1986), DIRECTOR.BAS (1989), DIRECTRY.BAS (1984), DISASM.BAS (1984), DISBURSE.BAS (1983), DISK.BAS (1990), DISKCAT.BAS (1983), DISKIDX.BAS (1985), DISKMDF2.BAS (1983), DISKMOD.BAS (1982), DISKMODF.BAS (1983), DISKMODP.BAS (1985), DISKPGM1.BAS (1982), DISPFILE.BAS (1982), DISPGRAF.BAS (1982), DISPGRDR.BAS (1982), DISPLAY.BAS (1981), DISPLAY.BAS (1983), DISPLAY.BAS (1989), DISPMAIL.BAS (1982), DISPMEMB.BAS (1982), DISTAR.BAS (1982), DITHER.BAS (1984), DLTAPLOT.BAS (1985), DLTAPRNT.BAS (1984), DM.BAS (1983), DOC.BAS (1987), DOCSWAN.BAS (1980), DOCSWAN.BAS (1980), DOCTOR.BAS (1982), DOCUFDOC.BAS (1987), DOCUFILE.BAS (1983), DOCUFILE.BAS (1987), DOLLAR.BAS (1984), DOORS.BAS (1985), DOORS.BAS (1985), DOSCOLOR.BAS (1984), DOSPOOL.BAS (1990), DOTDISP.BAS (1990), DOTS.BAS (1980), DOTS.BAS (1982), DOWN.BAS (1980), DPC.BAS (1988), DPM.BAS (1988), DRAGRACE.BAS (1980), DRAW.BAS (1982), DRAWGRAF.BAS (1982), DRAWIT.BAS (1983), DRAWPLUS.BAS (1986), DRIVE.BAS (1980), DRIVER.BAS (1980), DRIVER.BAS (1983), DRIVETST.BAS (1983), DROGANYA.BAS (1987), DROIDS.BAS (1983), DRVTEST.BAS (1984), DRYSTORE.BAS (1980), DSKHND.BAS (1983), DSKPGM2.BAS (1980), DSKTEST.BAS (1984), DSKTST.BAS (1983), DSTAT.BAS (1990), DT.BAS (1987), DTEXFILE.BAS (1982), DUMP.BAS (1982), DUMPSCRN.BAS (1984), DUMPSDIF.BAS (1983), DUNCHAR.BAS (1985), DUNEND.BAS (1985), DUNGEON.BAS (1980), DUNGEON.BAS (1987), DUNMAP.BAS (1985), DUNPLAY.BAS (1985), DUNQUEST.BAS (1985), DUNSHOP.BAS (1985), DWNLOAD.BAS (1982), DYNE.BAS (1986), E1.BAS (1982), E2.BAS (1980), E3.BAS (1982), EASEL.BAS (1982), EASTER.BAS (1985), EASYFILE.BAS (1982), EASYGRAF.BAS (1982), EASYMAIL.BAS (1982), EASYRITE.BAS (1987), EASYRITE.BAS (1987), EASYWORD.BAS (1987), EDDIE.BAS (1985), EDIPAGE.BAS (1980), EDIT.BAS (1979), EDIT.BAS (1991), EDITNO.BAS (1983), EDLIN.BAS (1980), EDUC.BAS (1988), ED_AM.BAS (1987), EFS.BAS (1983), EGGS.BAS (1980), EIGHTCRV.BAS (1985), EIGHTDAY.BAS (1990), EISLAND.BAS (1980), ELECTION.BAS (1985), ELECTRIC.BAS (1982), ELEPHANT.BAS (1982), ELIZA.BAS (1982), ELIZA.BAS (1983), EMBEDDED.BAS (1982), EMBEDDED.BAS (1983), EMPIRE.BAS (1987), EMSFRM.BAS (1990), EMSINFO.BAS (1990), END.BAS (1980), END.BAS (1984), END.BAS (1989), ENGINE.BAS (1982), ENTEP.BAS (1980), ENTER.BAS (1980), EPBENCHI.BAS (1985), EPIMRG.BAS (1986), EPISTAT.BAS (1986), EPSONSET.BAS (1987), EPSONUTL.BAS (1983), EQNSOLVE.BAS (1979), EQUAT.BAS (1987), EQUIP.BAS (1990), ERASCN.BAS (1990), ERFERFC.BAS (1984), ERFIND.BAS (1991), ERG.BAS (1986), ERRANAL.BAS (1980), ERROR.BAS (1980), ESCKEY.BAS (1987), ESOLVE.BAS (1988), ESSXFADE.BAS (1982), ET4.BAS (1983), EUCHRE.BAS (1984), EVRONWRD.BAS (1980), EXAMP1.BAS (1988), EXAMP1.BAS (1991), EXAMP2.BAS (1988), EXAMP2.BAS (1991), EXAMP3.BAS (1988), EXAMP3.BAS (1991), EXAMP4.BAS (1988), EXAMP4.BAS (1991), EXAMP5.BAS (1988), EXAMP5.BAS (1991), EXAMP6.BAS (1988), EXAMP6.BAS (1991), EXAMP7.BAS (1988), EXAMP8.BAS (1988), EXAMPLE.BAS (1987), EXAMPLE.BAS (1991), EXISTS.BAS (1990), EXPAND.BAS (1982), EXPENSE.BAS (1985), EXPER.BAS (1988), EXPERT.BAS (1980), EXPFIT.BAS (1984), EZ-MENU.BAS (1985), EZCODE1.BAS (1985), EZFDOCM.BAS (1982), FACTOR.BAS (1980), FACTORY.BAS (1990), FAMILY.BAS (1989), FARMBID.BAS (1980), FC.BAS (1984), FCBCRT.BAS (1983), FCBEXM.BAS (1983), FCBREAD.BAS (1985), FCC.BAS (1986), FCT1.BAS (1988), FCT2.BAS (1988), FCT3.BAS (1987), FEEDPIGS.BAS (1980), FEEDSILO.BAS (1984), FEEDVALU.BAS (1980), FENCE.BAS (1982), FENCE.BAS (1982), FENTRY-U.BAS (1990), FENTRY-U.BAS (1990), FF.BAS (1990), FFILE.BAS (1985), FFILEBIG.BAS (1985), FGAL.BAS (1986), FIFTEEN.BAS (1983), FIGDAT-U.BAS (1990), FILECAB.BAS (1984), FILECMD.BAS (1983), FILECMD2.BAS (1983), FILECOPY.BAS (1980), FILEDATE.BAS (1987), FILEFILE.BAS (1982), FILEFIX.BAS (1985), FILELIST.BAS (1980), FILEMENU.BAS (1982), FILEOUT.BAS (1983), FILESORT.BAS (1982), FILETRAN.BAS (1986), FILTER.BAS (1980), FILTER.BAS (1982), FILTER.BAS (1984), FIN.BAS (1986), FINANCE.BAS (1980), FINANCE.BAS (1982), FINANCE.BAS (1983), FINANCE.BAS (1983), FINANCE.BAS (1983), FINANCE1.BAS (1982), FIND-DS.BAS (1985), FINDFILE.BAS (1990), FINDFILE.BAS (1990), FINDSAT.BAS (1985), FINISH.BAS (1982), FINISH.BAS (1982), FINISHTX.BAS (1982), FINPAK.BAS (1982), FINPGM.BAS (1980), FIREFIRE.BAS (1982), FISHERS.BAS (1986), FIX-TEST.BAS (1983), FIXFILES.BAS (1983), FIXIT.BAS (1983), FIXPIC.BAS (1985), FIXTABS.BAS (1989), FIXTEXT.BAS (1984), FLAG.BAS (1980), FLASH.BAS (1984), FLASH.BAS (1985), FLASH.BAS (1990), FLASHCRD.BAS (1983), FLASHDAN.BAS (1984), FLIPPER.BAS (1983), FLIT.BAS (1986), FLY.BAS (1980), FLYBY.BAS (1982), FOILS.BAS (1982), FONTEDIT.BAS (1984), FOOT.BAS (1986), FOOTBAL.BAS (1985), FOOTBALL.BAS (1980), FOOTBALL.BAS (1985), FORM.BAS (1983), FORMDISP.BAS (1980), FORMGEN.BAS (1982), FORNEXT.BAS (1980), FORNEXT.BAS (1980), FORTH.BAS (1980), FORTRANS.BAS (1986), FORWARD.BAS (1983), FOS.BAS (1983), FOS2.BAS (1982), FOURIER.BAS (1980), FOZ.BAS (1986), FPINT.BAS (1986), FPLOT.BAS (1983), FQT.BAS (1986), FRANK.BAS (1982), FRANK.BAS (1986), FREQPLOT.BAS (1985), FRM.BAS (1984), FROG.BAS (1986), FROG.BAS (1988), FT2.BAS (1986), FT3.BAS (1986), FTELL.BAS (1992), FTLB.BAS (1986), FTPDL.BAS (1986), FULLEDIT.BAS (1980), FULLSCRN.BAS (1984), FUN.BAS (1980), FUNC1.BAS (1982), FUNC2.BAS (1979), FUNCT.BAS (1988), FUNGEN.BAS (1989), FUTRDATE.BAS (1983), FUTURE.BAS (1982), G1.BAS (1980), G2.BAS (1980), G3.BAS (1980), G4.BAS (1980), G5.BAS (1980), GALAXY.BAS (1983), GALAXY2.BAS (1980), GALILEAN.BAS (1987), GALLERY.BAS (1982), GAMMA(X).BAS (1980), GASFORM.BAS (1987), GATDECUP.BAS (1980), GDEMO.BAS (1985), GDUMP.BAS (1982), GDUMP1.BAS (1982), GDUMP2.BAS (1982), GEM’PRTR.BAS (1985), GENERAL.BAS (1986), GENERAL.BAS (1989), GENLEGER.BAS (1987), GENLEGER.BAS (1987), GENLGR.BAS (1989), GENPATCH.BAS (1984), GETCWD.BAS (1990), GETSP.BAS (1985), GETSP1.BAS (1985), GL.BAS (1988), GLACTS.BAS (1989), GLIDER.BAS (1987), GLOBE.BAS (1983), GOBBLE.BAS (1982), GODCREAT.BAS (1980), GODFATHR.BAS (1982), GOLDING.BAS (1989), GOLF.BAS (1982), GOLF2.BAS (1983), GOLFCARD.BAS (1984), GOTO.BAS (1980), GOTO.BAS (1980), GPRINT.BAS (1982), GR.BAS (1980), GR.BAS (1980), GRADES.BAS (1985), GRAF.BAS (1983), GRAFGE.BAS (1983), GRAFHAT.BAS (1982), GRAFTRAX.BAS (1983), GRAMF.BAS (1986), GRAMM.BAS (1986), GRAPH.BAS (1983), GRAPH1.BAS (1982), GRAPH2.BAS (1983), GRAPHICS.BAS (1980), GRAPHIT.BAS (1982), GREATCIR.BAS (1979), GREATRHM.BAS (1979), GREEKRTS.BAS (1980), GRINCH.BAS (1985), GROUP.BAS (1989), GROWTH.BAS (1980), GROWTH.BAS (1982), GROWTH.BAS (1983), GROWTH1.BAS (1982), GROWTH2.BAS (1982), GRPH64K.BAS (1983), GRTCRCL1.BAS (1987), GSDUMP.BAS (1983), GTEST.BAS (1981), GTFLP.BAS (1987), GUESS.BAS (1980), GUESS.BAS (1980), GUESS_1.BAS (1980), GUESS_2.BAS (1980), GUIDE.BAS (1980), GUIDE.BAS (1980), GUITAR.BAS (1984), H1.BAS (1980), H2.BAS (1980), HAIKU.BAS (1985), HALLEY.BAS (1985), HAMCALC.BAS (1985), HAMHELP.BAS (1985), HAMMODEM.BAS (1985), HAMURABI.BAS (1980), HAMURABI.BAS (1980), HANDSGEN.BAS (1986), HANGMAN.BAS (1982), HANGMAN.BAS (1982), HANOI.BAS (1982), HANOI.BAS (1983), HAPPYB.BAS (1981), HAPPYB.BAS (1983), HARDCASH.BAS (1984), HARMOSC.BAS (1984), HATDANCE.BAS (1980), HAYCRAB.BAS (1984), HAYESTST.BAS (1984), HAYSMODM.BAS (1983), HBDEMO.BAS (1990), HBDEMO.BAS (1990), HDRAW.BAS (1983), HEADCLN.BAS (1987), HEADER.BAS (1990), HEAPSORT.BAS (1985), HEARING.BAS (1979), HEARING.BAS (1983), HEBREW.BAS (1985), HELLO.BAS (1984), HELMET.BAS (1985), HELPCOM.BAS (1982), HELPPLUS.BAS (1980), HEX.BAS (1980), HEXCONV.BAS (1982), HEXPRINT.BAS (1987), HEXSAY.BAS (1987), HEXTODEC.BAS (1980), HGCTEST.BAS (1987), HGCTEST.BAS (1987), HIDEFILE.BAS (1983), HIDEFILE.BAS (1983), HIDESEEK.BAS (1983), HIQUE.BAS (1983), HIQUE2.BAS (1983), HIRESCOL.BAS (1984), HIRESNUD.BAS (1988), HISTGRAM.BAS (1982), HISTOGRM.BAS (1986), HLP3.BAS (1987), HLP3.BAS (1988), HOBBIT.BAS (1980), HOME-INV.BAS (1984), HORSE.BAS (1980), HOST.BAS (1982), HOST2.BAS (1982), HOUR.BAS (1986), HP7470A.BAS (1983), HPHR.BAS (1986), HPII.BAS (1990), HQ.BAS (1980), HRSCRSET.BAS (1990), HRSERACE.BAS (1983), HRZMENU.BAS (1980), HUFFMAN.BAS (1990), HUNGRHAP.BAS (1983), HUSTLE.BAS (1983), IBBS.BAS (1983), IBMCS.BAS (1980), IBMDIY.BAS (1980), IBMLABEL.BAS (1987), IBMMC.BAS (1980), IBMSONG.BAS (1982), IBMSONG.BAS (1983), ICICLE.BAS (1980), IDSPRISM.BAS (1983), IFTHEN.BAS (1980), IFTHEN.BAS (1983), IFTHEN.BAS (1980), IGAL.BAS (1986), IN2.BAS (1986), IN3.BAS (1986), INCH.BAS (1986), INCOME.BAS (1982), INCOME.BAS (1984), INDEX.BAS (1983), INDEX1.BAS (1987), INDEX2.BAS (1987), INDEXMAR.BAS (1989), INDEXPC.BAS (1989), INDXCARD.BAS (1983), INIT-U.BAS (1990), INIT-U.BAS (1990), INKEY.BAS (1985), INKEY2.BAS (1985), INPUSING.BAS (1990), INPUT.BAS (1980), INPUT.BAS (1980), INSAT.BAS (1984), INSERT.BAS (1982), INSTALL.BAS (1984), INSTR.BAS (1983), INSULIN.BAS (1987), INTCAL.BAS (1988), INTEREST.BAS (1980), INTERMOD.BAS (1985), INTERP3.BAS (1980), INTERP4.BAS (1980), INTLCVID.BAS (1980), INTRATE.BAS (1986), INTRO.BAS (1983), INTRO.BAS (1985), INTRO.BAS (1988), INTROD.BAS (1990), INTRODUC.BAS (1986), INTRODUC.BAS (1989), INVEN.BAS (1982), INVENPRC.BAS (1984), INVENRPT.BAS (1984), INVENTRY.BAS (1980), INVHISTO.BAS (1986), INVINCOM.BAS (1986), INVPRICE.BAS (1986), INVRECOV.BAS (1980), INVVALUE.BAS (1986), INVYIELD.BAS (1986), IPCOGOLF.BAS (1982), IPLOT.BAS (1987), IPLOT.BAS (1988), IQBUILD.BAS (1982), IQBUILD.BAS (1985), IQUEEN.BAS (1983), IRA.BAS (1980), IRA.BAS (1986), ISLAND.BAS (1989), ITALICS.BAS (1982), J2000.BAS (1987), JAIME.BAS (1980), JAMMER.BAS (1982), JBREAK.BAS (1982), JESUS.BAS (1986), JESUSLOV.BAS (1982), JET.BAS (1985), JETPILOT.BAS (1980), JETSET.BAS (1980), JETSET.BAS (1980), JOULE.BAS (1986), JOURNEY.BAS (1989), JOYSTEST.BAS (1983), JOYSTICK.BAS (1982), JOYSTIK.BAS (1985), JSB.BAS (1984), JSB.BAS (1984), JUKEBOX.BAS (1980), JUKEBOX.BAS (1980), JULIAN.BAS (1985), JUMBLE.BAS (1983), K0.BAS (1983), K1.BAS (1980), K1.BAS (1983), K2.BAS (1980), K2.BAS (1983), K3.BAS (1980), K4.BAS (1980), K5.BAS (1980), KALCOL.BAS (1980), KALEID.BAS (1982), KALK.BAS (1985), KANGAROO.BAS (1984), KBDFIX.BAS (1983), KBD_FIX.BAS (1980), KB_FLAG.BAS (1983), KB_FLAG.BAS (1984), KCAL.BAS (1986), KENO.BAS (1980), KEPLER.BAS (1985), KEPLER.BAS (1987), KEY.BAS (1983), KEY.BAS (1986), KEYCREAT.BAS (1990), KEYDEF.BAS (1980), KEYDEMO.BAS (1990), KEYDEMO1.BAS (1990), KEYMOVE.BAS (1984), KEYPAD.BAS (1984), KEYPUNCH.BAS (1982), KEYS.BAS (1983), KEYSBAS.BAS (1983), KEYSET.BAS (1986), KEYSET.BAS (1987), KEYSMP.BAS (1983), KEYSTAT.BAS (1984), KGF.BAS (1986), KGM.BAS (1986), KILL.BAS (1980), KILL.BAS (1983), KILL2.BAS (1985), KILLNULL.BAS (1982), KING.BAS (1980), KINGDOM.BAS (1980), KIT.BAS (1980), KM.BAS (1986), KM2.BAS (1986), KM3.BAS (1986), KNOCK.BAS (1982), KSCOPE.BAS (1986), KSPRBAS.BAS (1990), KWH.BAS (1986), KWHR.BAS (1986), KYBD.BAS (1982), KYBD.BAS (1982), L2FILMS.BAS (1980), LABELEPS.BAS (1982), LABELPRT.BAS (1984), LABELS.BAS (1982), LABLFILE.BAS (1987), LABLFILE.BAS (1987), LABMAIL.BAS (1982), LABPRINT.BAS (1982), LABSELEC.BAS (1982), LANDER.BAS (1980), LANDER.BAS (1982), LANDER.BAS (1982), LANDER.BAS (1983), LANDPUR.BAS (1984), LANDSEQ.BAS (1982), LARMOR.BAS (1980), LASERJET.BAS (1987), LBANNER.BAS (1980), LBF.BAS (1986), LBL-BAS.BAS (1983), LBL-SAMP.BAS (1983), LBM.BAS (1986), LDIR.BAS (1982), LDIRC.BAS (1982), LEAS-BY1.BAS (1984), LEASE.BAS (1982), LEGENDRE.BAS (1984), LEM.BAS (1983), LET.BAS (1980), LET.BAS (1983), LET.BAS (1980), LETTER.BAS (1983), LEYGREF1.BAS (1987), LIBMAKE.BAS (1990), LIBMAKE.BAS (1990), LIEBESTR.BAS (1983), LIFE.BAS (1981), LIFE2.BAS (1980), LIFE2.BAS (1984), LILSPROG.BAS (1989), LINEBUG.BAS (1984), LINEQNS.BAS (1980), LINES.BAS (1980), LINLSQR.BAS (1984), LINREGR.BAS (1980), LINREGRS.BAS (1982), LIST1.BAS (1984), LISTER.BAS (1980), LISTER.BAS (1984), LISTER.BAS (1987), LISTFILE.BAS (1982), LISTMAIL.BAS (1982), LISTMAR.BAS (1989), LISTPCI.BAS (1989), LISTPER.BAS (1989), LITUPLIF.BAS (1982), LJLBAR39.BAS (1990), LNREGRES.BAS (1986), LOADPIC.BAS (1984), LOAN-MTG.BAS (1984), LOAN.BAS (1983), LOAN.BAS (1984), LOAN2.BAS (1982), LOAN3.BAS (1983), LOANANAL.BAS (1983), LOANCOST.BAS (1986), LOANQUAL.BAS (1986), LOANS.BAS (1985), LOANSVGS.BAS (1983), LOANTERM.BAS (1986), LOCMAIL.BAS (1982), LOCSTIME.BAS (1985), LODEMO.BAS (1984), LOF.BAS (1989), LOGCONV.BAS (1985), LOGCURVE.BAS (1980), LOGO40.BAS (1980), LOGOC.BAS (1981), LOGOFF.BAS (1985), LOGON.BAS (1985), LOGPRINT.BAS (1985), LONGTERM.BAS (1984), LONGZONE.BAS (1983), LOOKUP.BAS (1982), LORES.BAS (1984), LOSTGOLD.BAS (1983), LOTTO.BAS (1985), LPCTALK.BAS (1982), LPT12SET.BAS (1987), LQ.BAS (1983), LRNCRVPR.BAS (1987), LRNCRVSC.BAS (1987), LRS.BAS (1982), LSQPARAB.BAS (1980), LSQREXP.BAS (1984), LSQRPR.BAS (1987), LSQRSC.BAS (1987), LSTRANGE.BAS (1990), LUDWIG.BAS (1983), LUMBER.BAS (1985), LUNAR.BAS (1982), LUNAR.BAS (1982), LWINTRO.BAS (1990), M1.BAS (1982), M10.BAS (1982), M11.BAS (1982), M12.BAS (1982), M13.BAS (1982), M14.BAS (1983), M15.BAS (1983), M16.BAS (1982), M17.BAS (1983), M18.BAS (1982), M19.BAS (1982), M2.BAS (1982), M2.BAS (1986), M20.BAS (1983), M21.BAS (1983), M22.BAS (1983), M23.BAS (1983), M24.BAS (1982), M25.BAS (1983), M26.BAS (1983), M3.BAS (1982), M3.BAS (1986), M4.BAS (1982), M5.BAS (1982), M6.BAS (1982), M7.BAS (1982), M8.BAS (1983), M9.BAS (1982), MA.BAS (1984), MA.BAS (1985), MAGDALEN.BAS (1980), MAGDALEN.BAS (1983), MAIL.BAS (1983), MAIL1.BAS (1983), MAILIST1.BAS (1983), MAILIST1.BAS (1983), MAILIST2.BAS (1982), MAILLIST.BAS (1982), MAILMEMB.BAS (1982), MAILMENU.BAS (1982), MAILSORT.BAS (1983), MAILSORT.BAS (1983), MAILTIPS.BAS (1988), MAIN.BAS (1980), MAIN.BAS (1980), MAIN.BAS (1985), MAKE.BAS (1990), MAKE.BAS (1990), MAKEDATA.BAS (1984), MAKEDOTS.BAS (1985), MAKEFIDX.BAS (1989), MAKEMEMO.BAS (1983), MAKETABS.BAS (1989), MAKSTKFL.BAS (1983), MANOR.BAS (1980), MAPTREE.BAS (1985), MARS-ESC.BAS (1985), MASTER.BAS (1982), MASTER2.BAS (1983), MASTMIND.BAS (1982), MATERBAL.BAS (1980), MATH.BAS (1980), MATH.BAS (1982), MATH.BAS (1982), MATH.BAS (1983), MATH.BAS (1983), MATH.BAS (1985), MATH.BAS (1980), MATHF.BAS (1989), MATHFUNC.BAS (1982), MATOP.BAS (1990), MATRDIAG.BAS (1984), MATRINV.BAS (1984), MATRIX.BAS (1983), MAXIT.BAS (1982), MAZE.BAS (1980), MAZE.BAS (1982), MCNEMAR.BAS (1986), MDRAW.BAS (1983), MEAN.BAS (1982), MEDBULL.BAS (1980), MEDLEY.BAS (1984), MEGATREK.BAS (1984), MEMBERS.BAS (1982), MEMBRAIN.BAS (1980), MEMDUMP.BAS (1983), MEMO.BAS (1983), MEMO.BAS (1984), MEMORY.BAS (1980), MEMORY.BAS (1983), MEMORY.BAS (1984), MEMPEEK.BAS (1983), MEMSET.BAS (1980), MEMSIZE.BAS (1983), MENU.BAS (1980), MENU.BAS (1980), MENU.BAS (1980), MENU.BAS (1980), MENU.BAS (1980), MENU.BAS (1980), MENU.BAS (1982), MENU.BAS (1982), MENU.BAS (1982), MENU.BAS (1982), MENU.BAS (1982), MENU.BAS (1983), MENU.BAS (1983), MENU.BAS (1985), MENU.BAS (1985), MENU.BAS (1985), MENU.BAS (1986), MENU.BAS (1987), MENU.BAS (1988), MENU.BAS (1989), MENU.BAS (1980), MENU.BAS (1989), MENU2.BAS (1980), MENU2.BAS (1983), MENUMAKR.BAS (1984), MENUPRNT.BAS (1987), MENUS-U.BAS (1990), MENUS-U.BAS (1990), MESSIAH.BAS (1983), METEOR.BAS (1980), METEOR.BAS (1980), METEOR.BAS (1982), METER.BAS (1986), METRICON.BAS (1985), MEZ.BAS (1987), MHCHIMLT.BAS (1986), MHCHISQR.BAS (1986), MI3.BAS (1986), MICE.BAS (1990), MICRON.BAS (1986), MICROS.BAS (1986), MIL.BAS (1986), MIL2.BAS (1986), MIL3.BAS (1986), MILE.BAS (1986), MILE2.BAS (1986), MILLIS.BAS (1986), MIN.BAS (1986), MINI-WP.BAS (1982), MINI.BAS (1987), MINIMATH.BAS (1980), MINIPROG.BAS (1983), MINUET.BAS (1983), MINUET.BAS (1983), MINUET2.BAS (1983), MISC-U.BAS (1990), MISC-U.BAS (1990), MISSING.BAS (1980), MISSING.BAS (1989), MISSING.BAS (1980), MISSLE.BAS (1980), MLOAD.BAS (1990), MLTIBRST.BAS (1980), MM.BAS (1986), MM2.BAS (1986), MM3.BAS (1986), MNTHINCM.BAS (1986), MOD100IN.BAS (1983), MODES.BAS (1980), MODES.BAS (1980), MODULO.BAS (1983), MOLY-PAY.BAS (1983), MOMSKKUR.BAS (1984), MONAMORT.BAS (1987), MONEYMKT.BAS (1985), MONITOR.BAS (1982), MONO.BAS (1980), MONO.BAS (1983), MONOFILE.BAS (1982), MONOGRAF.BAS (1982), MONOSET.BAS (1983), MONSW.BAS (1982), MONTHLYO.BAS (1986), MONTOCOL.BAS (1982), MONYM.BAS (1988), MOON.BAS (1980), MOON.BAS (1982), MOON.BAS (1983), MORSE.BAS (1987), MORSE1.BAS (1985), MORSE2.BAS (1985), MORSECOD.BAS (1987), MORSECRV.BAS (1980), MORTGAGE.BAS (1985), MOUNTAIN.BAS (1980), MPG-CAL.BAS (1980), MPG.BAS (1980), MPG.BAS (1980), MSPCBOOT.BAS (1984), MSPCTRAN.BAS (1984), MSQUARE.BAS (1983), MSRBBOO.BAS (1984), MTN-KING.BAS (1983), MULTID.BAS (1980), MULTPULS.BAS (1980), MUSIC.BAS (1980), MUSIC.BAS (1983), MUSIC.BAS (1983), MUSICBOX.BAS (1983), MUSICBOX.BAS (1984), MUSICFIL.BAS (1984), MX80.BAS (1982), NADIA.BAS (1983), NATINST.BAS (1990), NCCLSPRE.BAS (1983), NECPLOT7.BAS (1983), NECPRINT.BAS (1983), NETPREST.BAS (1982), NETWORK.BAS (1985), NEWACT.BAS (1989), NEWCHARS.BAS (1984), NEWCHESS.BAS (1983), NEWFONT.BAS (1984), NEWKEY.BAS (1982), NEWTON.BAS (1986), NEWTONRT.BAS (1980), NEWTREK.BAS (1982), NEXTSHOW.BAS (1982), NFL-PK.BAS (1983), NICELIST.BAS (1987), NIM.BAS (1982), NIM.BAS (1982), NISTSYNC.BAS (1991), NMILE.BAS (1986), NMILE2.BAS (1986), NMR-ABC.BAS (1980), NMR-ABCD.BAS (1980), NMR-WEFT.BAS (1980), NMR0.BAS (1985), NMR1.BAS (1985), NMR2.BAS (1985), NMR3.BAS (1985), NMR4.BAS (1985), NMR5.BAS (1985), NMR6.BAS (1985), NMREXCH.BAS (1980), NMREXEC.BAS (1980), NMRFOURT.BAS (1980), NMRPHASE.BAS (1980), NMRRELAX.BAS (1980), NMRROT.BAS (1980), NOBRKCOM.BAS (1983), NOISE.BAS (1982), NONLIN.BAS (1982), NORESET.BAS (1984), NORMAL-Z.BAS (1982), NORMAL.BAS (1986), NOTEPAD.BAS (1991), NOTESAND.BAS (1986), NOTICE.BAS (1985), NPAD.BAS (1985), NSEC.BAS (1986), NTP.BAS (1980), NUDE.BAS (1983), NUDE.BAS (2025), NUKE-NY.BAS (1983), NUKE-SF.BAS (1984), NUM-WORD.BAS (1983), NUM2.BAS (1982), NUM2WORD.BAS (1985), NUM3.BAS (1982), NUMBERS.BAS (1982), NUMDAYS.BAS (1986), NUMDIFF.BAS (1980), NUMERIC.BAS (1982), NUMVERT.BAS (1983), NUMZAP.BAS (1984), NUTCRAKR.BAS (1983), NUTREK.BAS (1984), NWCLOCK.BAS (1983), NYLOGO.BAS (1984), OBJGEN.BAS (1988), OBJSPEC.BAS (1988), OBLITER8.BAS (1988), OFFRES.BAS (1980), OK84ASET.BAS (1983), OKIDLCG.BAS (1987), OKIMENU.BAS (1984), OKIMENUC.BAS (1984), OKITALIC.BAS (1984), OPERATOR.BAS (1982), OPKEYS.BAS (1983), OPNBAL.BAS (1989), OSCAR.BAS (1985), OSCFREQ.BAS (1985), OSCPLOT.BAS (1985), OSCUPLK.BAS (1985), OTHDEMO.BAS (1982), OTHELLO.BAS (1980), OTHELLO.BAS (1980), OTHELLO.BAS (1982), OUTLINE1.BAS (1988), OUTLINE2.BAS (1988), OVERVIEW.BAS (1986), OVERVIEW.BAS (1989), OZF.BAS (1986), OZM.BAS (1986), PAINT.BAS (1980), PAK-DATE.BAS (1985), PAL80.BAS (1984), PALLETTE.BAS (1983), PANDL.BAS (1989), PARABOLA.BAS (1985), PARSECMD.BAS (1990), PASSWORD.BAS (2025), PASSWORD.BAS (1987), PATCHER.BAS (1984), PATCHER.BAS (1984), PATHMAN.BAS (1982), PATTERNS.BAS (1982), PATTERNS.BAS (1982), PATTERNS.BAS (1983), PAYBACK.BAS (1986), PAYMENT.BAS (1983), PAYROLL.BAS (1985), PBCOPY.BAS (1990), PBS.BAS (1987), PBTOUCH.BAS (1990), PC-CALC.BAS (1984), PC-CHECK.BAS (1980), PC-COLOR.BAS (1987), PC-GRAF2.BAS (1985), PC-GRAF3.BAS (1985), PC-GRAF4.BAS (1985), PC-LIB.BAS (1983), PC-MAP.BAS (1983), PC-PAD.BAS (1983), PC-PAD.BAS (1983), PC-SPEAK.BAS (1983), PC-SPELL.BAS (1984), PC-TALK.BAS (1982), PC-TOUCH.BAS (1985), PCBD.BAS (1985), PCFILECH.BAS (1983), PCFORM.BAS (1982), PCGLOBE.BAS (1983), PCGLOBE.BAS (1983), PCHALLEN.BAS (1982), PCHEERS.BAS (1982), PCIGEN.BAS (1984), PCINIT.BAS (1982), PCINPUT.BAS (1984), PCKEY.BAS (1984), PCMAN.BAS (1982), PCMAN.BAS (1982), PCMAN.BAS (1984), PCT3VT.BAS (1983), PD200.BAS (1990), PDDEMO.BAS (1990), PDL.BAS (1986), PDRAW.BAS (1980), PEARSON.BAS (1980), PEEK.BAS (1983), PEEKPRNT.BAS (1987), PENCIL.BAS (1980), PENCIRC.BAS (1982), PENCLEAR.BAS (1982), PENDRAW.BAS (1982), PENGUIN.BAS (1985), PENLINE.BAS (1982), PENPAINT.BAS (1982), PENSAVE.BAS (1982), PEOPLE.BAS (1982), PEPLSYST.BAS (1987), PEPSON.BAS (1983), PERBALAN.BAS (1986), PERCENT.BAS (1984), PERDEPOS.BAS (1986), PERMEXM2.BAS (1991), PERMEXMP.BAS (1991), PERMFONT.BAS (1991), PERMFPBU.BAS (1991), PERMUTE.BAS (1982), PERPCAL.BAS (1980), PERRATE.BAS (1986), PERS.BAS (1985), PERSONAL.BAS (1980), PERT.BAS (1982), PERT3.BAS (1983), PERTCHRT.BAS (1983), PERTCHT.BAS (1982), PERTERM.BAS (1986), PGBRK.BAS (1985), PGMCVRT.BAS (1984), PH1.BAS (1988), PH2.BAS (1988), PH3.BAS (1988), PH4.BAS (1988), PH5.BAS (1988), PH6.BAS (1988), PHASER.BAS (1982), PHASERB.BAS (1982), PHOENIX.BAS (1983), PHONELST.BAS (1987), PIANO1.BAS (1980), PIANO2.BAS (1980), PICKER.BAS (1984), PICKTRAN.BAS (1984), PICTURE.BAS (1980), PIE.BAS (1984), PIECHART.BAS (1982), PIG.BAS (1985), PINWHEEL.BAS (1980), PIRATE.BAS (1980), PLIC.BAS (1987), PLIC.BAS (1987), PLIC.BAS (1988), PLOG.BAS (1987), PLOG.BAS (1988), PLOT.BAS (1982), PLOTM.BAS (1987), PLOTM.BAS (1988), PLOTTER.BAS (1981), PLOTTER.BAS (1984), PLTSTKFL.BAS (1983), PMB15.BAS (1987), PMLOF2.BAS (1990), PMMAC.BAS (1990), PMPBWIND.BAS (1991), POINTS.BAS (1986), POISSON.BAS (1986), POLRECT.BAS (1985), PONGPONG.BAS (1980), PORT4.BAS (1990), PORTCOST.BAS (1984), PORTMRKT.BAS (1984), POST.BAS (1989), POSTER.BAS (1983), POSTER.BAS (1983), POWRCURV.BAS (1980), PPLOT.BAS (1987), PPLOT.BAS (1988), PRAELUD1.BAS (1983), PRAELUD2.BAS (1983), PRDEMO.BAS (1981), PRECESS.BAS (1985), PRESCH.BAS (1980), PRGTIM.BAS (1984), PRINGRAF.BAS (1982), PRINT.BAS (1980), PRINT.BAS (1980), PRINT.BAS (1981), PRINT.BAS (1982), PRINT.BAS (1980), PRINTCON.BAS (1985), PRINTDIF.BAS (1983), PRINTER.BAS (1982), PRINTER.BAS (1982), PRINTER2.BAS (1982), PRINTERS.BAS (1985), PRINTERS.BAS (1985), PRINTERS.BAS (1989), PRINTES1.BAS (1983), PRINTING.BAS (1980), PRINTING.BAS (1980), PRINTMAN.BAS (1980), PRINTMAN.BAS (1984), PRINTMAR.BAS (1989), PRINTNEC.BAS (1982), PRINTPER.BAS (1989), PRINTQUE.BAS (1980), PRLIST.BAS (1980), PRN2GRAF.BAS (1982), PRNSTATS.BAS (1984), PRNT2.BAS (1983), PRNT3.BAS (1984), PRNTCALL.BAS (1987), PRNTGRAF.BAS (1982), PRNTSAVE.BAS (1982), PROBS.BAS (1989), PROFILE.BAS (1982), PROFILER.BAS (1982), PROGHEAD.BAS (1987), PROJECTS.BAS (1984), PROVERB1.BAS (1982), PRTEXTRA.BAS (1980), PRTGRAF.BAS (1982), PRTSC.BAS (1985), PRTSET.BAS (1983), PSCREEN.BAS (1983), PSEC.BAS (1986), PSQUISH.BAS (1983), PSTCLS.BAS (1989), PSTYLES.BAS (1981), PSWDFILE.BAS (1990), PSWDWRIT.BAS (1990), PUBVARS.BAS (1990), PUBVARS.BAS (1990), PUBVARS.BAS (1990), PUFF.BAS (1982), PUNYCALC.BAS (1983), PUPPY.BAS (1985), PUSH.BAS (1985), PVTAX.BAS (1982), PWW.BAS (1989), PWW.BAS (1990), Q.BAS (1983), Q4T-DEMO.BAS (1990), QB-TO-TB.BAS (1987), QBDEMO.BAS (1988), QBNEST.BAS (1989), QBSCR.BAS (1990), QPRINT.BAS (1983), QSORT.BAS (1982), QSORT.BAS (1985), QUEST.BAS (1986), QUICKC.BAS (1985), QUICKCHA.BAS (1987), QUICKREF.BAS (1983), QUICKSRT.BAS (1980), QUIZ.BAS (1985), QUOTATIO.BAS (1989), QUOTINST.BAS (1989), QUOTREV.BAS (1989), R1.BAS (1980), R2.BAS (1980), R3.BAS (1980), R4.BAS (1980), R5.BAS (1980), RABBIT.BAS (1985), RACE.BAS (1983), RACECAR.BAS (1985), RAIL.BAS (1983), RANDOM.BAS (1985), RANDOMIZ.BAS (1986), RANDSEED.BAS (1987), RANGERD.BAS (1980), RANKTEST.BAS (1986), RATEADJ.BAS (1986), RATION.BAS (1984), RATS.BAS (1990), RBBS-PC.BAS (1984), RBBS-PC.BAS (1990), RBBS-VAR.BAS (1990), RBBSSUB1.BAS (1990), RBBSSUB2.BAS (1990), RBBSSUB3.BAS (1990), RBBSSUB4.BAS (1990), RBBSSUB5.BAS (1990), RBBSUTIL.BAS (1982), RCV.BAS (1987), READ123.BAS (1989), READBAS.BAS (1984), READDATA.BAS (1980), READDATA.BAS (1980), READING.BAS (1982), README.BAS (1983), README.BAS (1988), READTEMP.BAS (1991), READTEMP.BAS (1991), READ_DIR.BAS (1985), REAL$.BAS (1983), REALPGM.BAS (1980), REBOOT.BAS (1990), RECONFIG.BAS (1990), RECTPOL.BAS (1985), REF.BAS (1990), REFER.BAS (1988), REFERENC.BAS (1986), REFERENC.BAS (1989), REFLEX.BAS (1985), REFORM.BAS (1985), REFSHT.BAS (1988), REGRESS.BAS (1982), REGRESS.BAS (1982), REGRESS.BAS (1984), REGRS.BAS (1989), REKEY.BAS (1983), REM.BAS (1980), REMAK.BAS (1989), REMARKS.BAS (1984), REMARKS1.BAS (2080), REMARKS2.BAS (2080), REMARKS3.BAS (2080), REMARKS4.BAS (2080), REMARKST.BAS (2080), REMCACC.BAS (1982), REMOTE.BAS (1987), REMOVE.BAS (1982), REMREM.BAS (1983), RENUM.BAS (1985), RENUMEMB.BAS (1982), REORDERS.BAS (1988), REORMAIL.BAS (1982), REPEAT.BAS (1983), REPORT.BAS (1984), REPORTOR.BAS (1983), REPORTS.BAS (1980), REPORTS.BAS (1985), RESCMD.BAS (1983), RESCMD.BAS (1983), RESCMDCK.BAS (1983), RESISTOR.BAS (1985), RESTATTR.BAS (1980), RESUME.BAS (1980), RETRIEVE.BAS (1989), REVERSE.BAS (1980), REVIEW.BAS (1980), REVUMEMB.BAS (1982), RHMLINE.BAS (1979), RIDDLES.BAS (1980), RIEMAN.BAS (1980), RING.BAS (1984), RMEX079.BAS (1990), RMEX085.BAS (1990), RMEX106.BAS (1990), RMEX122.BAS (1990), RMEX145.BAS (1990), RMEX160.BAS (1990), RMEX173.BAS (1990), RMEX174.BAS (1990), RMEX175.BAS (1990), RMEX182.BAS (1990), RMEX195.BAS (1990), RMEX198.BAS (1990), RMEX230.BAS (1990), RMEX232.BAS (1990), RMEX282.BAS (1990), RMEX288.BAS (1990), RMEX290.BAS (1990), RMEX291.BAS (1990), ROADRALY.BAS (1983), ROBOTNKA.BAS (1985), ROCK.BAS (1989), ROCKET.BAS (1980), ROCKET1.BAS (1987), ROD.BAS (1982), ROLAND.BAS (1986), ROLODEX.BAS (1984), ROMBASIC.BAS (1984), ROMBIOS.BAS (1984), ROMCHAR.BAS (1982), ROMREAD.BAS (1980), ROOTFHLF.BAS (1980), ROULETTE.BAS (1980), ROULETTE.BAS (1980), ROUNDER.BAS (1980), ROUNDER1.BAS (1980), ROUNDER2.BAS (1980), ROUNDER3.BAS (1980), ROUNDER4.BAS (1980), ROWCOL.BAS (1983), RP-HELP.BAS (1985), RPTUSE.BAS (1984), RTTYTALK.BAS (1984), RUBIC.BAS (1980), RUBIC3.BAS (1983), RUBIK.BAS (1983), RULEOF78.BAS (1986), RUNFIRST.BAS (1985), RUNFIRST.BAS (1985), RUNFIRST.BAS (1986), RUNOFF.BAS (1982), RUTHEXPT.BAS (1984), RUTHSCAT.BAS (1984), RV-EDIT.BAS (1982), RV-EDIT.BAS (1983), RVAR0227.BAS (1990), S1.BAS (1979), S1.BAS (1980), S10.BAS (1983), S11.BAS (1979), S12.BAS (1983), S13.BAS (1982), S14.BAS (1983), S15.BAS (1982), S16.BAS (1983), S17.BAS (1982), S18.BAS (1982), S2.BAS (1980), S2.BAS (1983), S3.BAS (1980), S3.BAS (1982), S4.BAS (1980), S4.BAS (1982), S5.BAS (1980), S5.BAS (1982), S6.BAS (1980), S6.BAS (1983), S7.BAS (1980), S7.BAS (1982), S8.BAS (1983), S9.BAS (1979), SAMECHK.BAS (1985), SAMPDRAW.BAS (1982), SAMPLE.BAS (1983), SAMPLE.BAS (1984), SAMPLE.BAS (1990), SAMPLES.BAS (1983), SAMPLSIZ.BAS (1986), SAMPRPT1.BAS (1990), SATFIND2.BAS (1985), SATFIND4.BAS (1987), SATURN.BAS (1981), SATURN.BAS (1982), SAVEGRAF.BAS (1982), SAVER.BAS (1991), SAVHISTO.BAS (1986), SAVINGS.BAS (1987), SCALES.BAS (1984), SCAN.BAS (1983), SCANP2.BAS (1990), SCATRGRM.BAS (1986), SCHEDU.BAS (1984), SCHWABCM.BAS (1983), SCISUBV1.BAS (1982), SCN-DEMO.BAS (1984), SCN-DEMO.BAS (1984), SCN-DEMO.BAS (1984), SCNMAP.BAS (1983), SCOPE.BAS (1982), SCR-COLN.BAS (1985), SCR-COLY.BAS (1985), SCR-DATA.BAS (1985), SCR-MENU.BAS (1985), SCR-MONN.BAS (1985), SCR-MONY.BAS (1985), SCRAMBLE.BAS (1980), SCRAMBLE.BAS (1982), SCRAMBLE.BAS (1988), SCRAMBLE.BAS (1980), SCREEN.BAS (1980), SCREEN.BAS (1980), SCREEN.BAS (1982), SCREEN.BAS (1984), SCREEN.BAS (1986), SCREEN.BAS (1987), SCREEN.BAS (1990), SCREEN1.BAS (1980), SCREEN2.BAS (1980), SCREEN3.BAS (1980), SCREEN4.BAS (1980), SCREEN5.BAS (1980), SCREENIN.BAS (1984), SCRLDEMO.BAS (1985), SCRN-MAP.BAS (1984), SCRN-WK.BAS (1985), SCRNAMRT.BAS (1985), SCRNDUMP.BAS (1985), SCRNMOVE.BAS (1987), SCROLL.BAS (1984), SCROLL.BAS (1985), SCROLL1.BAS (1983), SCROLL2.BAS (1983), SCROLLK.BAS (1983), SEAWOLF.BAS (1985), SEC&BYTE.BAS (1983), SEC.BAS (1986), SECRETNO.BAS (1980), SEESWTCH.BAS (1983), SELECT.BAS (1986), SELTRA.BAS (1989), SERIAL.BAS (1980), SERIALNO.BAS (1982), SERPENT.BAS (1980), SESAME.BAS (1983), SETDRIVE.BAS (1984), SETDRV.BAS (1985), SETIT.BAS (1988), SETKEY.BAS (1984), SETMEM.BAS (1985), SETUP-H.BAS (1990), SETUP.BAS (1983), SETUP.BAS (1989), SETUP.BAS (1989), SFG-BACH.BAS (1984), SHARE.BAS (1985), SHELLSRT.BAS (1980), SHELLSRT.BAS (1982), SHELLSRT.BAS (1984), SHELSORT.BAS (1980), SHELSORT.BAS (1985), SHIELDS.BAS (1982), SHIFTS.BAS (1982), SHOP.BAS (1980), SHORTERM.BAS (1984), SHORTSUB.BAS (1985), SHOWBOX.BAS (1987), SHOWCHRS.BAS (1990), SHOWMEMO.BAS (1983), SHUTTL3D.BAS (1988), SHUTTLE.BAS (1980), SIDEREAL.BAS (1987), SIMONSEZ.BAS (1984), SIMPINT.BAS (1980), SIMPINV.BAS (1986), SIMPLEX.BAS (1985), SINSTALL.BAS (1984), SIREN.BAS (1980), SIREN.BAS (1982), SIXBOXES.BAS (1987), SIY2LINR.BAS (1989), SIZER.BAS (1983), SKELETON.BAS (1984), SKELETON.BAS (1984), SKETCH.BAS (1980), SLEEVE.BAS (1987), SLEEVE.BAS (1987), SLOT.BAS (1980), SLOT.BAS (1984), SLOTCOLR.BAS (1980), SLOTMACH.BAS (1983), SLOTMACH.BAS (1983), SLOTMACH.BAS (1984), SLUG.BAS (1986), SMITH.BAS (1985), SMURF.BAS (1983), SNAKE.BAS (1989), SNOOPY.BAS (1980), SNOW1.BAS (1982), SNOW2.BAS (1982), SNOW3.BAS (1982), SOLAR.BAS (1980), SOLFE.BAS (1983), SOLITAIR.BAS (1984), SOLITARE.BAS (1984), SONGS.BAS (1982), SORRY.BAS (1982), SORT-BLK.BAS (1982), SORT.BAS (1980), SORT.BAS (1982), SORT.BAS (1983), SORTDIC.BAS (1984), SORTDIF.BAS (1982), SORTEST.BAS (1983), SORTINT.BAS (1980), SORTS.BAS (1982), SORTSTR.BAS (1980), SOUND1.BAS (1982), SOUNDEFF.BAS (1983), SOUNDEMO.BAS (1983), SOUNDS.BAS (1983), SOUNDS.BAS (1983), SOVIET.BAS (1987), SOWINDEX.BAS (1984), SPEC-OCC.BAS (1983), SPECPROB.BAS (1980), SPECTERN.BAS (1990), SPEECH.BAS (1982), SPEEDUP.BAS (1982), SPELL.BAS (1983), SPELLBEE.BAS (1980), SPELLDAT.BAS (1980), SPELLER.BAS (1982), SPELLING.BAS (1980), SPELLING.BAS (1986), SPINECHO.BAS (1980), SPINOUT.BAS (1980), SPINOUT.BAS (1982), SPIRO.BAS (1984), SPKDEMO.BAS (1990), SPLOT.BAS (1987), SPLOT.BAS (1988), SPLTSCRN.BAS (1985), SPOOLBAS.BAS (1982), SPRITE.BAS (1984), SPROGH.BAS (1989), SPSHIPS.BAS (1982), SQUARE.BAS (1980), SQUARE.BAS (1983), SQUARE.BAS (1983), SQUISH.BAS (1983), SQUISHER.BAS (1984), SR.BAS (1980), SRS.BAS (1982), SS.BAS (1980), SSREMARK.BAS (1980), STAR.BAS (1985), STAR2001.BAS (1985), STARFIND.BAS (1985), STARLANE.BAS (1982), STARMAP.BAS (1983), STARS.BAS (1980), START.BAS (1981), START.BAS (1982), START.BAS (1984), START.BAS (1984), START.BAS (1986), START.BAS (1988), STARTBAS.BAS (1983), STARTREK.BAS (1980), STARTREK.BAS (1982), STARTREK.BAS (1982), STARTREK.BAS (1982), STARTREK.BAS (1982), STARTREK.BAS (1982), STARTREK.BAS (1983), STARTREK.BAS (1986), STARTRK2.BAS (1982), STARTUP.BAS (1980), STARTUP.BAS (1987), STARWARS.BAS (1983), STAT.BAS (1983), STATCAPS.BAS (1983), STATFILE.BAS (1982), STATMAIL.BAS (1982), STATMEMB.BAS (1982), STATS.BAS (1985), STEERBID.BAS (1984), STICK.BAS (1983), STICK.BAS (1987), STOACT.BAS (1989), STOCK.BAS (1985), STOPGAP.BAS (1983), STORM.BAS (1985), STORY.BAS (1980), STRIKE9.BAS (1980), STRINGS.BAS (1982), SUBDEMO.BAS (1984), SUBGRAF2.BAS (1985), SUBGRAF3.BAS (1985), SUBGRAF4.BAS (1985), SUMMARY.BAS (1988), SUNNY.BAS (1985), SUNSET.BAS (1984), SUPERDIR.BAS (1980), SUPRTREK.BAS (1982), SUPSCRAM.BAS (1980), SUPSCRAM.BAS (1980), SURFGEN.BAS (1989), SURFPR.BAS (1983), SURROUND.BAS (1979), SURVIVAL.BAS (1982), SURVIVAL.BAS (1982), SURVIVAL.BAS (1983), SW-PEG.BAS (1983), SWARMS.BAS (1983), SWIRL.BAS (1980), SWW.BAS (1990), SWW.BAS (1990), SYMPH-5.BAS (1983), SYNCSAT.BAS (1987), SYNONYM.BAS (1982), SYNONYM2.BAS (1982), SYNONYMS.BAS (1980), SYNTH.BAS (1980), SYS.BAS (1983), T-ROAD.BAS (1980), T-TEST.BAS (1986), TABDOC.BAS (1989), TABLE.BAS (1990), TABLEOFC.BAS (1986), TABLEOFC.BAS (1989), TABLET.BAS (1982), TABLET.BAS (1984), TABS.BAS (1984), TADAA.BAS (1982), TADADADA.BAS (1982), TALKDEMO.BAS (1988), TALKPAGE.BAS (1980), TANK.BAS (1983), TANKS.BAS (1980), TARGET.BAS (1983), TASKLIST.BAS (1987), TASKPLAN.BAS (1984), TAXDEDCT.BAS (1984), TAXMAN.BAS (1980), TCLOCK.BAS (1983), TEACHER.BAS (1985), TEACHER.BAS (1985), TEACHER.BAS (1985), TEACHER.BAS (1985), TEACHER.BAS (1985), TEACHER.BAS (1985), TEACHER.BAS (1985), TELLTIME.BAS (1983), TEMP.BAS (1980), TEMP.BAS (1980), TEMP.BAS (1990), TEMPCONV.BAS (1982), TEMPFDMO.BAS (1991), TEMPFPBU.BAS (1991), TEMPGRAF.BAS (1982), TEMPLE.BAS (1980), TERM.BAS (1983), TERMDEPO.BAS (1986), TEST.BAS (1982), TEST.BAS (1982), TESTASCI.BAS (1983), TESTDRV.BAS (1983), TESTPRNT.BAS (1982), TESTPROG.BAS (1980), TESTSCRN.BAS (1981), TESTWRIT.BAS (1987), TEXTPROC.BAS (1985), TFL.BAS (1985), THANKS.BAS (1988), THINGFIL.BAS (1987), TICCLOCK.BAS (1982), TICKTOCK.BAS (1982), TICTACTO.BAS (1982), TICTACTO.BAS (1982), TILEEQ.BAS (1992), TIME.BAS (1983), TIMEAL.BAS (1985), TIMEDEMO.BAS (1984), TIMER.BAS (1985), TIMESHOW.BAS (1987), TIMING.BAS (1983), TITLE.BAS (1984), TITLE2.BAS (1984), TITLEPG.BAS (1985), TM-BREAK.BAS (1982), TM-DIAL2.BAS (1982), TM-LDIR1.BAS (1982), TM-TIME1.BAS (1982), TMDAY.BAS (1983), TMSTRT.BAS (1984), TMT.BAS (1987), TNODE.BAS (1987), TODAY.BAS (1990), TODAYU.BAS (1990), TORPEDOB.BAS (1982), TOUCH.BAS (1990), TOUT.BAS (1985), TRACE.BAS (1984), TRADE.BAS (1980), TRADER.BAS (1983), TRAILER.BAS (1982), TRANDUMP.BAS (1981), TRANDUMP.BAS (1983), TRANSFER.BAS (1982), TRANSFER.BAS (1983), TRAP.BAS (1983), TRAUMERI.BAS (1983), TREASURE.BAS (1980), TREASURE.BAS (1990), TREASURY.BAS (1982), TREE.BAS (1983), TREEFIX.BAS (1985), TREK.BAS (1982), TRIANGLE.BAS (1980), TRIBAL.BAS (1989), TRIDIAG.BAS (1980), TRONLC.BAS (1980), TRS2PC.BAS (1983), TRUCK.BAS (1987), TRUCK.BAS (1988), TRUCKER.BAS (1982), TRUMPET.BAS (1983), TTD100.BAS (1990), TTD101.BAS (1990), TTD105.BAS (1990), TTDIR100.BAS (1990), TTDIR101.BAS (1990), TTDIR105.BAS (1990), TTENTER.BAS (1984), TTEST.BAS (1990), TTEST5.BAS (1990), TTNOTE.BAS (1985), TTOWERS.BAS (1984), TTRULES.BAS (1984), TTY22.BAS (1985), TUNE.BAS (1983), TUTOR.BAS (1983), TWINKLE.BAS (1983), TWOLINE.BAS (1980), TWOMEANS.BAS (1980), TWORD.BAS (1990), TWOSIDE.BAS (1982), TXTSCAN.BAS (1983), TYPE.BAS (1980), TYPE.BAS (1985), TYPE.BAS (1980), TYPING.BAS (1980), TYPING.BAS (1980), U-MIND.BAS (1984), UASM-LST.BAS (1984), ULOGO.BAS (1984), UMEX227.BAS (1990), UMEX230.BAS (1990), UMEX233.BAS (1990), UMEX235.BAS (1990), UMEX238.BAS (1990), UMEX258.BAS (1990), UMEX262.BAS (1990), UMEX300.BAS (1990), UNDO.BAS (1984), UNDOBKUP.BAS (1984), UNSCRAM.BAS (1988), UNWS.BAS (1983), UPBEAT.BAS (1982), UPCASE.BAS (1985), UPDATMAR.BAS (1989), UPDATORD.BAS (1989), UPDATPER.BAS (1989), UPDLOAD.BAS (1982), UPDMEMB.BAS (1982), UPLINK.BAS (1985), UPPER.BAS (1983), USALIST.BAS (1980), USAT.BAS (1985), USERDOCS.BAS (1984), USERMANU.BAS (1985), USINGTHE.BAS (1986), USINGTHE.BAS (1989), USLE.BAS (1985), USRINIT1.BAS (1983), USRINIT2.BAS (1983), UTMP.BAS (1984), UTSCAN.BAS (1982), V.BAS (1991), VAMPIRE.BAS (1984), VARIABLE.BAS (1983), VDEMO.BAS (1991), VERB.BAS (1980), VERBAR.BAS (1988), VHF-YAGI.BAS (1985), VPDEMO1.BAS (1990), VPLOT.BAS (1987), VPLOT.BAS (1988), VSD.BAS (1987), VUE.BAS (1983), WAITIN.BAS (1981), WALLS.BAS (1980), WALLST.BAS (1985), WAR.BAS (1985), WARGAMES.BAS (1980), WATERFOW.BAS (1985), WB-UPTLE.BAS (1982), WEATHER.BAS (1983), WEBB.BAS (1991), WEDPRICE.BAS (1988), WEEK.BAS (1986), WEEKDAYS.BAS (1985), WEIGHTFM.BAS (1987), WELCOME.BAS (1982), WELLTEMP.BAS (1980), WHACPU.BAS (1990), WHATSON.BAS (1986), WHEEL.BAS (1980), WHEEL.BAS (1984), WHEEL.BAS (1985), WHERE.BAS (1985), WHEREIS.BAS (1980), WHLABELS.BAS (1987), WHOLE.BAS (1980), WILCX.BAS (1990), WILLTELL.BAS (1980), WILLTELL.BAS (1983), WINDCHIL.BAS (1982), WINDDEMO.BAS (1990), WISLAND.BAS (1989), WIZARD.BAS (1983), WMTELL.BAS (1983), WOMBATS.BAS (1986), WOODHEAT.BAS (1985), WORDFREQ.BAS (1983), WORDPLAY.BAS (1982), WORDS.BAS (1984), WORLDMAP.BAS (1983), WORM1.BAS (1982), WORMCITY.BAS (1980), WRITECOM.BAS (1984), WRITEDIF.BAS (1983), WS-ASCII.BAS (1983), WS-DOS.BAS (1983), WS-DOS.BAS (1984), WSPATCH2.BAS (1985), WSPNEC35.BAS (1983), WUMPUS.BAS (1982), WURD.BAS (1980), WURD.BAS (1980), X10.BAS (1988), X10TEST.BAS (1988), XAPRIN.BAS (1984), XCGAVU.BAS (1989), XMAS.BAS (1979), XMAS.BAS (1984), XMASCARD.BAS (1983), XRAYDIF1.BAS (1980), XREF.BAS (1984), XREFMOD.BAS (1982), XTAB.BAS (1986), XTMENU.BAS (2090), XUP.BAS (1983), XWING.BAS (1983), XWING.BAS (1985), XYZ.BAS (1985), YA1LOOK.BAS (1984), YAHTZEE.BAS (1982), YAHTZEE.BAS (1982), YAHTZEE.BAS (1982), YAHTZEE.BAS (1983), YAHTZEE.BAS (1987), YARD.BAS (1986), YD2.BAS (1986), YD3.BAS (1986), YEAR.BAS (1986), YESORNO.BAS (1987), YESTER.BAS (1980), YOURMENU.BAS (1987), YOURVOWN.BAS (1985), ZAP’EM.BAS (1980), ZAP’EM.BAS (1982), ZAP-EM.BAS (1982), ZAPDEB.BAS (1984), ZAPTRE.BAS (1984), ZELLER.BAS (1982), ZIP.BAS (1990), ZIPCLEAR.BAS (1987), ZOOSORT.BAS (1980), ZOOTIME.BAS (1982), ZSCOR.BAS (1989), ZYLGIS.BAS (1983),

The PC-SIG Library and ZIP Files

Thu, 06 Apr 2023 10:00:00 +0000

The PC Software Interest Group, aka PC-SIG, began advertising a directory of public domain software for the IBM PC in early 1983. A year later, their collection featured over 135 diskettes, which you could purchase for $6 per diskette, plus $4 per order for shipping. Each diskette was numbered, to make it easy to specify which diskettes you wanted. By 1986, PC-SIG was one of the most prominent advertisers of user-supported software (“shareware”), sold annual memberships, and had a collection of nearly 500 diskettes.

As CD-ROM technology became popular in late 1980s, PC-SIG began distributing their library on CD-ROM as well. As of 1987, the library contained over 700 diskettes, so this was a much more convenient and economical way to get the collection.

So far, I’ve seen only five of their CD-ROM releases:

8th Edition (April 1990, Diskettes 1-2121)
9th Edition (December 1990, Diskettes 1-2485)
10th Edition (September 1991, Diskettes 1-2804)
12th Edition (March 1993, Diskettes 1-3404, 2929 Available)
13th Edition (March 1994, Diskettes 1-4313, 3064 Available)

I recently acquired the 8th Edition CD-ROM, previously unavailable except as a collection of files on Jason Scott’s website, cd.textfiles.com (see “PC-SIG Library Eighth Edition From PC-SIG (April 1990)”), so I uploaded a copy of the CD-ROM to the Internet Archive.

I’m sure there were more than those five CD-ROMs. There was probably an 11th Edition released in 1992. And “CD ROM” releases were mentioned in their advertisements going back to at least September 1987, so the 8th Edition was definitely not the first CD-ROM release.

PC-SIG “editions” were not limited to CD-ROM releases, because at some point, their printed directories were labeled as “editions”, too. Another recent acquisition was a copy of “The PC-SIG Library 4th Edition”, published in March 1987, which I’ve also uploaded to the Internet Archive.

On page 424 of that directory, there is a picture of their “February 1987” CD-ROM, and while the CD-ROM does not appear to mention any “edition”, it would likely be considered the “PC-SIG Library 4th Edition” CD-ROM. It was probably the first CD-ROM that PC-SIG produced, too, based on that early date. At $295, it was also rather expensive, which means that not many people may have bought it, which may explain why the disc hasn’t shown up anywhere – at least not yet.

The layout of the PC-SIG CD-ROMs changed over time. In the 8th Edition, the contents of each diskette were deposited in the their own folder. For example, Disk #1 was stored in /001_100/DISK0001/:

Oct  3  1985 ASK.COM
Jan  1  1970 BLACKJCK.BAS
Jun 11  1986 CASPAR.BAT
Jun 11  1986 CASPAR.HLP
Jun 11  1986 CASPAR0.HLP
Jun 11  1986 CASPAR1.HLP
Jun 11  1986 CASPAR2.HLP
Jun 11  1986 CASPAR3.HLP
Jan  1  1970 CIRCLES.BAS
Mar 26  1983 COPYOVER.BAT
Mar 26  1983 COPYOVER.DOC
Feb  2  1982 DOTS.BAS
May 28  1987 FILES001.TXT
Jan  1  1970 HATDANCE.BAS
Mar 26  1982 KALEID.BAS
Mar 26  1982 MAXIT.BAS
Dec 24  1982 MENU.BAS
Jan  1  1970 OTHELLO.BAS
Sep  8  1982 PATTERNS.BAS
Jan  1  1970 PONGPONG.BAS
Mar 26  1983 SAMPLES.BAS
Mar 26  1982 STRINGS.BAS
Jun 17  1986 WOMBATS.BAS
Jun 10  1986 WOMBATS.DOC
Jun 10  1986 WOMBATS.WP
Mar 26  1982 YAHTZEE.BAS

However, beginning with the 9th Edition, diskette contents were stored on the CD-ROM as ZIP files (eg, DISK0001.ZIP through DISK2485.ZIP).

As PC-SIG explained, ZIP files were initially used on a case-by-case basis to preserve filenames that were not allowed on CD-ROM, but eventually it was done for all diskettes to save space as well:

“This zipping was necessary because the High Sierra Format and MS-DOS Extensions allow only the characters A through Z, 0 through 9, and _(underscore) in filenames. Some of our nearly 30,000 files include other characters, so rather than change the original filename given by the author, we elected to zip those files and give the newly created zipped files allowable filenames. (Every disks’ files were zipped on the Ninth Edition in order to fit, as we had approached the maximum for a CD on the Eighth Edition.)”

[More details about the PC-SIG CD-ROM can be found in the CD-ROM Booklet that I included with my upload].

It turns out there was another good for reason using for using ZIP files: on a CD-ROM, all files in a directory are stored in ascending (alphabetical) order, which would ruin the “DIR” listing order that some diskette authors depended on. For example, Disk #798 used filenames with line-drawing characters unique to the IBM PC:

A:\>DIR

 Volume in drive A has no label
 Directory of  A:\

DEMO     BAT      114   5-02-87  11:44a
PMENU    DOC    25407   8-01-88  11:28a
BRUN40   EXE    76816  10-08-87   5:57p
MENGEN   EXE    67847   8-01-88  10:32a
MG-C     EXE     6723   8-01-88  10:34a
MG-M     EXE     5261   8-01-88  10:35a
MGHLP    EXE    26805   8-01-88  10:37a
PLIC     EXE     4791   8-01-88  10:38a
PMENU    EXE    21215   7-30-88   4:57p
DEMO     HLP     8562   5-05-87  12:16p
DEMO     MEN     5115   5-02-87  12:36p
M        MEN     1371   7-30-88  12:55p
FILES798 TXT     2178   8-25-88   2:09p
GO       BAT       38   7-02-87  11:29a
GO       TXT      463   7-02-87  11:29a
┌─┬─┬─┐             0
│T│G│S│             0
│Y│O│T│             0
│P│                 0
│E│T│R│             0
│                   0
└─┴─┴─┘             0
       22 File(s)     60416 bytes free

While ZIP files did incidentally preserve file order, the ZIP format was not specifically designed for disk preservation (no volume labels, for example), and in the particular case of DISK0798, some filenames were still mangled at some point (though not necessarily by PKZIP), because the directory listing was probably intended to display as:

┌─┬─┬─┐
│T│G│S│
│Y│O│T│
│P│  A│
│E│T│R│
│ │O│T│
└─┴─┴─┘

Another interesting difference between CD-ROM editions was their degree of “completeness”. At first glance, the 9th Edition CD-ROM would appear to include every diskette from 0001 through 2485, but it turns out that at least 165 of diskettes had their contents removed from the library. The ZIP file for those 165 diskettes contains nothing more than a NOTE.TXT that says:

╔═════════════════════════════════════════════════════════════════════════╗
║   This disk has been withdrawn by the author from the PC-SIG library.   ║
╚═════════════════════════════════════════════════════════════════════════╝

Later CD-ROM editions didn’t bother including folders or ZIP files for removed or obsolete diskettes, which is why I noted above that the 12th Edition had only 2929 disks available (out of 3404 total), and the 13th Edition had only 3064 available (out of 4313 total).

Putting the PC-SIG Library Online

Some years ago, I added part of the PC-SIG Library to PCjs; specifically, the PC-SIG Library 8th Edition CD-ROM (April 1990). That process involved recreating 2121 diskette images from folders, and then producing four web pages, each with an IBM PC and directory listings for 500+ diskettes, along with buttons to load the desired diskette into the PC.

But I wanted to do something better – something more comprehensive and user-friendly.

So I’ve added the PC-SIG Diskette Library: The (Almost) Complete Collection, featuring over 4000 diskettes from all the available CD-ROMs, and supplemented with diskette images of actual PC-SIG diskettes where available.

Every disk now has its own page, and the PC-SIG Diskette Library page offers a very rudimentary search capability to help you find the program or diskette you’re looking for. I’ve also started adding PC-SIG documentation for each diskette to the individual pages. Work on both search and documentation is on-going.

Creating Disk Images from ZIP Files

Although I prefer original disk images, ZIP files are the next best thing, and while the standard practice of “unzipping” a ZIP file into a directory and then running DiskImage with the --dir option works, it’s not ideal for several reasons, some of which were touched on above:

While a ZIP file does (incidentally) preserve the order of the files as they appeared on the original diskette, modern operating systems do not, so the process of “unzipping” usually destroys that order.
DOS file attributes and file modification dates and times are not always accurately preserved by modern operating systems.
DOS filenames containing special characters from the IBM PC character set (ie, Code Page 437) are almost always mangled in the process.

For all those reasons, I decided to update DiskImage with a new --zip option. It can now read and decompress the contents of an entire ZIP file into memory and then create a disk image, preserving the order of files, as well as the original attributes, dates, times, and filenames.

Next, I updated DiskImage’s --extract option to automatically convert CP437 filenames to UTF-8 filenames, so by combining --zip and --extract, you can effectively “unzip” a ZIP file into your file system and not get mangled filenames – even if they included PC graphics characters.

I also decided to “expand” on that feature with a new --expand option, so that any .ZIP files inside a ZIP file can be decompressed, too. For example, if you have a BACKUP.ZIP that contains a DOCS.ZIP, the --expand option (in conjunction with --extract) will create a directory named DOCS.ZIP containing the decompressed contents of the DOCS ZIP file. This feature should work for any number of nested ZIP files.

Extracting BASIC Program Listings

Last but not least, the PC-SIG collection contained a large number of BASIC programs, which I thought would be nice to include listings of on the individual PC-SIG diskette pages. Unfortunately, in those days, .BAS files were usually stored in tokenized (non-ASCII) format, since that was BASIC’s default SAVE behavior and the files were slightly smaller.

So, I added yet another DiskImage option (--normalize) to automatically convert tokenized .BAS files to CP437 text files (or UTF-8 files if extracting to your local file system). As an added bonus, I included the ability to detect “protected” (encrypted) .BAS files and “de-protect” them in the process.

These “de-tokenization” and “de-protection” processes seemed straight-forward at first, thanks to several useful online resources that I credit in the source code (eg, https://github.com/rwtodd/bascat and https://slions.net), but de-tokenization is actually a bit trickier than most people realize, in part because they didn’t know how inventive BASIC programmers were in the early days of the IBM PC.

For example, some programmers liked to include PC graphics characters inside their strings, comments, and DATA statements – which BASIC was perfectly fine with. However, all the de-tokenization code and pseudo-code I saw would misidentify those characters as BASIC tokens. There were also a few other tricky details, like rendering floating-point constants with the correct precision, appending ‘#’ to double-precision constants, etc.

Here’s just one example of the use of non-ASCII characters inside strings and comments, from PC-SIG Disk #241:

3300 REM ▬ OTHER OTHELLO BOARD
3310 CLS:LOCATE 1,10:PRINT "O T H E L L O"
3320 LOCATE 3,5:PRINT"1   2   3   4   5   6   7   8"
3330 FOR N=1 TO 8:LOCATE 3+2*N,1:PRINT CHR$(N+64):NEXT
3340 LOCATE 4,3  :PRINT"╔═══╦═══╦═══╦═══╦═══╦═══╦═══╦═══╗":FOR N=1 TO 13STEP 2
3350 LOCATE 4+N,3:PRINT"║   ║   ║   ║   ║   ║   ║   ║   ║"
3360 LOCATE 5+N,3:PRINT"╠═══╬═══╬═══╬═══╬═══╬═══╬═══╬═══╣":NEXT
3370 LOCATE 4+N,3:PRINT"║   ║   ║   ║   ║   ║   ║   ║   ║"
3380 LOCATE 5+N,3:PRINT"╚═══╩═══╩═══╩═══╩═══╩═══╩═══╩═══╝"
3390 FOR I= 1TO 8
3400 FOR J= 1 TO 8:LOCATE 2* J+ 3,4* I+ 1:FACE= (A(I,J)+ 3)/2
3410 IF FACE = 1.5 THEN PRINT" " ELSE PRINT CHR$(FACE)
3420 NEXT J,I
3430 GOSUB 3250
3440 RETURN

In short, the collection of PC-SIG .ZIP and .BAS files provided an excellent set of test cases for ZIP decompression and BASIC de-tokenization, and the PCjs DiskImage utility now has some handy new capabilities.

New PCjs Libraries

I started with node-stream-zip, added support for the ARC file format, and then extended its decompression support; like most modern ZIP utilities, it uses zlib, which supports only Deflate compression.

Here’s a list of the new JavaScript modules:

StreamZip.js, an improved version of the node-stream-zip package
Structure.js, a helper class that provides methods for defining and reading on-disk structures
LegacyZip.js, a decompression library used by StreamZip.js that adds support for:
- Packed files (ARC compression format #3)
- Squeezed files (ARC compression format #4)
- Crunched files (ARC compression formats #5, #6, and #7)
- Crushed files (ARC compression format #8)
- Squashed files (ARC compression format #9)
- Shrinked files (ZIP compression format #1)
- Reduced files (ZIP compression formats #2, #3, #4, and #5)
- Imploded files (ZIP compression format #6)
- Deflated files (ZIP compression format #8)
BASFile.js, a BASIC file de-tokenizer that also performs PC character conversion

The combination of StreamZip.js with LegacyZip.js should be able to decompress any old ARC or ZIP archive, so test it out with the new --arc and --zip options in the DiskImage utility, and if you find one that doesn’t work, let me know.

Last but not least, I’ve also added a BASIC Conversion Utility page that loads BASFile.js in your web browser. It should be able to convert any old IBM PC BASIC file to plain text, but again, if you run into any interesting discrepancies, let me know.

The Joys of Old ARC and ZIP Files

Tue, 07 Mar 2023 10:00:00 +0000

File compression became quite popular in the 1980s. People who used dial-up “BBS” bulletin board systems could transfer compressed data in less time, and people like me could squeeze more data onto 360K diskettes.

For IBM PC users, a popular compression solution was a “shareware” program named ARC written by Thom Henderson in 1985 and sold by his company, System Enhancement Associates (“SEA”). ARC was written entirely in C, using the Computer Innovations C86 Compiler, and the source code was available on request (note that the source code was copyrighted with “all rights reserved”; more on that later).

We take easy-to-use compression utilities for granted these days, but ARC was something of a novelty at the time. I probably used ARC version 5.12 to produce many of my early .ARC files:

ARC - Archive utility, Version 5.12, created on 02/05/86 at 22:22:01
(C) COPYRIGHT 1985,86 by System Enhancement Associates; ALL RIGHTS RESERVED

Please refer all inquiries to:

       System Enhancement Associates
       21 New Street, Wayne NJ 07470

You may copy and distribute this program freely, provided that:
    1)   No fee is charged for such copying and distribution, and
    2)   It is distributed ONLY in its original, unmodified state.

If you like this program, and find it of use, then your contribution will
be appreciated.  You may not use this product in a commercial environment
or a governmental organization without paying a license fee of $35.  Site
licenses and commercial distribution licenses are available.  A program
disk and printed documentation are available for $50.

If you fail to abide by the terms of this license,  then your conscience
will haunt you for the rest of your life.

Usage: ARC {amufdxerplvtc}[bswn][g<password>] <archive> [<filename> . . .]
Where:   a   = add files to archive
         m   = move files to archive
         u   = update files in archive
         f   = freshen files in archive
         d   = delete files from archive
         x,e = extract files from archive
         r   = run files from archive
         p   = copy files from archive to standard output
         l   = list files in archive
         v   = verbose listing of files in archive
         t   = test archive integrity
         c   = convert entry to new packing method
         b   = retain backup copy of archive
         s   = suppress compression (store only)
         w   = suppress warning messages
         n   = suppress notes and comments
         g   = Encrypt/decrypt archive entry

Please refer to the program documentation for complete instructions.

Here’s how you would use it to, for example, archive your entire MS-DOS 3.20 directory:

C:\> ARC A DOS.ARC C:\DOS\*.*
Creating new archive: DOS.ARC
Adding file:   ANSI.SYS       analyzing, packing, done.
Adding file:   APPEND.COM     analyzing, crunching, done.
Adding file:   ASSIGN.COM     analyzing, crunching, done.
Adding file:   ATTRIB.EXE     analyzing, crunching, done.
Adding file:   BACKUP.EXE     analyzing, crunching, done.
Adding file:   CHKDSK.EXE     analyzing, crunching, done.
Adding file:   COMMAND.COM    analyzing, squeezing, done.
Adding file:   DEBUG.EXE      analyzing, squeezing, done.
Adding file:   DISKCOMP.EXE   analyzing, crunching, done.
Adding file:   DISKCOPY.EXE   analyzing, crunching, done.
Adding file:   DRIVER.SYS     analyzing, crunching, done.
Adding file:   EDLIN.EXE      analyzing, crunching, done.
Adding file:   EXE2BIN.EXE    analyzing, crunching, done.
Adding file:   FC.EXE         analyzing, crunching, done.
Adding file:   FDISK.EXE      analyzing, crunching, done.
Adding file:   FIND.EXE       analyzing, crunching, done.
Adding file:   FORMAT.EXE     analyzing, crunching, done.
Adding file:   GRAFTABL.EXE   analyzing, crunching, done.
Adding file:   GRAPHICS.EXE   analyzing, crunching, done.
Adding file:   GWBASIC.EXE    analyzing, squeezing, done.
Adding file:   JOIN.EXE       analyzing, crunching, done.
Adding file:   KEYBDV.EXE     analyzing, crunching, done.
Adding file:   KEYBFR.EXE     analyzing, crunching, done.
Adding file:   KEYBGR.EXE     analyzing, crunching, done.
Adding file:   KEYBIT.EXE     analyzing, crunching, done.
Adding file:   KEYBSP.EXE     analyzing, crunching, done.
Adding file:   KEYBUK.EXE     analyzing, crunching, done.
Adding file:   LABEL.EXE      analyzing, crunching, done.
Adding file:   LINK.EXE       analyzing, crunching, done.
Adding file:   MODE.EXE       analyzing, crunching, done.
Adding file:   MORE.COM       analyzing, crunching, done.
Adding file:   PRINT.EXE      analyzing, crunching, done.
Adding file:   RAMDRIVE.SYS   analyzing, crunching, done.
Adding file:   RECOVER.EXE    analyzing, crunching, done.
Adding file:   REPLACE.EXE    analyzing, crunching, done.
Adding file:   RESTORE.EXE    analyzing, crunching, done.
Adding file:   SHARE.EXE      analyzing, crunching, done.
Adding file:   SORT.EXE       analyzing, packing, done.
Adding file:   SUBST.EXE      analyzing, crunching, done.
Adding file:   SYS.COM        analyzing, crunching, done.
Adding file:   TREE.EXE       analyzing, crunching, done.
Adding file:   XCOPY.EXE      analyzing, crunching, done.

C:\>DIR DOS.ARC

 Volume in drive C is PCJS ORG   
 Directory of  C:\

DOS      ARC   338459   7-07-86  12:00p

Listing the contents of DOS.ARC shows that the original total size of all the files was 426387, so the archive reduced that total by over 20% – not bad for a bunch of binary files. In 1986, that is.

C:\> ARC L DOS.ARC
Name          Length    Date     
============  ========  =========
ANSI.SYS          1651   7 Jul 86
APPEND.COM        1725   7 Jul 86
ASSIGN.COM        1523   7 Jul 86
ATTRIB.EXE        8234   7 Jul 86
BACKUP.EXE       23404   7 Jul 86
CHKDSK.EXE        9680   7 Jul 86
COMMAND.COM      23612   7 Jul 86
DEBUG.EXE        15647   7 Jul 86
DISKCOMP.EXE      3808   7 Jul 86
DISKCOPY.EXE      4096   7 Jul 86
DRIVER.SYS        1102   7 Jul 86
EDLIN.EXE         7356   7 Jul 86
EXE2BIN.EXE       3050   7 Jul 86
FC.EXE           14558   7 Jul 86
FDISK.EXE        16830   7 Jul 86
FIND.EXE          6403   7 Jul 86
FORMAT.EXE       11005   7 Jul 86
GRAFTABL.EXE      8210   7 Jul 86
GRAPHICS.EXE     13170   7 Jul 86
GWBASIC.EXE      78864   7 Jul 86
JOIN.EXE          9012   7 Jul 86
KEYBDV.EXE        2886   7 Jul 86
KEYBFR.EXE        2948   7 Jul 86
KEYBGR.EXE        2940   7 Jul 86
KEYBIT.EXE        2892   7 Jul 86
KEYBSP.EXE        2983   7 Jul 86
KEYBUK.EXE        2886   7 Jul 86
LABEL.EXE         2750   7 Jul 86
LINK.EXE         43988   7 Jul 86
MODE.EXE         13928   7 Jul 86
MORE.COM           282   7 Jul 86
PRINT.EXE         8824   7 Jul 86
RAMDRIVE.SYS      6462   7 Jul 86
RECOVER.EXE       4145   7 Jul 86
REPLACE.EXE       4852   7 Jul 86
RESTORE.EXE      21750   7 Jul 86
SHARE.EXE         8544   7 Jul 86
SORT.EXE          1898   7 Jul 86
SUBST.EXE         9898   7 Jul 86
SYS.COM           4607   7 Jul 86
TREE.EXE          8588   7 Jul 86
XCOPY.EXE         5396   7 Jul 86
        ====  ========
Total     42    426387  

Fast forward 35 years later. After reading thousands of old diskettes in storage and collecting all their contents onto my laptop, I noticed there were a lot of .ARC files (and even more .ZIP files), and since disk space was no longer a premium, I decided to expand them all.

Fortunately, the archive utility I use on my MacBook (“The Unarchiver”) has a command-line utility, unar, that knows how to deal with both .ARC and .ZIP files.

I wasn’t expecting the hundreds of old .ARC and .ZIP archives to decompress without issues, especially because a few of them had come from diskettes with unrecoverable read errors, but there were far more problems than I had expected.

The most common problem was actually with .ZIP files, and whenever unar ran into a problem, it wasn’t very helpful. For example:

unar -o BOXES3 PCMAG-VOL07N15/BOXES3.ZIP
BOXES3  (384 B)... OK.
BOXES3.C  (10496 B)... Failed! (File is not fully supported)
BOXES3.DEF  (384 B)... OK.
BOXES3.EXE  (5552 B)... Failed! (File is not fully supported)
BOXES3.H  (384 B)... OK.
BOXES3.RC  (3868 B)... Failed! (File is not fully supported)

The problem became clearer after running a vintage copy of PKUNZIP on the archives:

C:\TMP>PKUNZIP -V BOXES3.ZIP

PKUNZIP (tm)    FAST!    Extract Utility    Version 1.02    10-01-89
Copyright 1989 PKWARE Inc.  All Rights Reserved.  PKUNZIP/h for help

Searching ZIP: BOXES3.ZIP

 Length  Method   Size  Ratio   Date    Time   CRC-32  Attr  Name
 ------  ------   ----- -----   ----    ----   ------  ----  ----
    384  Shrunk     189  51%  05-13-88  16:27  301e262c --w  BOXES3
  10496  Reduce4   3019  72%  05-15-88  01:43  746c8158 --w  BOXES3.C
    384  Shrunk     247  36%  05-13-88  16:27  cd620860 --w  BOXES3.DEF
   5552  Reduce4   3827  32%  05-16-88  14:55  7dd8923c --w  BOXES3.EXE
    384  Shrunk     207  47%  05-13-88  16:24  84b5ba7c --w  BOXES3.H
   3868  Reduce4   1307  67%  08-01-88  04:49  b1f16a7f --w  BOXES3.RC
 ------          ------  ---                                 -------
  21068            8796  59%                                       6

Apparently, the Reduce4 compression method was short-lived, and as a result, almost no modern archive utilities support it. See this excellent write-up on legacy ZIP compression methods like Reduce for more details.

There were also number of .ARC files that had more mysterious problems. For example, I had three different .ARC backups of an old OS/2 utility I had written in early 1988 named “Cue”. It was a handy program that saved (“queued”) your OS/2 command-line history for quick recall and editing. Unfortunately, none of the three CUE.ARC archives could be completely decompressed. Here is what unar reported:

unar -o CUE -d CUE.ARC
CUE  (2151 B)... OK.
CUE.C  (20157 B)... Failed! (Error on decrunching)
CUE.DEF  (35 B)... Failed! (Wrong checksum)
CUE.DOC  (12913 B)... Failed! (Error on decrunching)
CUE.EXE  (16463 B)... Failed! (Data is corrupted)
CUE.H  (11829 B)... OK.
CUE.MAP  (13942 B)... Failed! (Error on decrunching)
CUE.OBJ  (8456 B)... Failed! (Data is corrupted)
CUE.SYM  (2228 B)... Failed! (Data is corrupted)
CUE.SYS  (1405 B)... Failed! (Data is corrupted)
CUECOMM.C  (5961 B)... OK.
CUECOMM.OBJ  (1710 B)... OK.
CUEFIND.C  (10264 B)... Failed! (Data is corrupted)
CUEFIND.OBJ  (3133 B)... Failed! (Data is corrupted)
CUEHIST.C  (7435 B)... Failed! (Data is corrupted)
CUEHIST.OBJ  (2379 B)... Failed! (Data is corrupted)
CUEKBD.C  (2958 B)... Failed! (Data is corrupted)
CUEKBD.OBJ  (911 B)... Failed! (Data is corrupted)
CUEKREG.C  (15653 B)... Failed! (Error on decrunching)
CUEKREG.OBJ  (4108 B)... Failed! (Data is corrupted)
CUEKSUP.C  (5623 B)... Failed! (Data is corrupted)
CUEKSUP.OBJ  (2010 B)... Failed! (Data is corrupted)
CUEMSE.C  (2404 B)... Failed! (Data is corrupted)
CUEMSE.OBJ  (672 B)... Failed! (Data is corrupted)
CUEPOP.C  (19345 B)... Failed! (Error on decrunching)
CUEPOP.OBJ  (5421 B)... Failed! (Data is corrupted)
CUEPROC.C  (8774 B)... Failed! (Data is corrupted)
CUEPROC.OBJ  (2675 B)... Failed! (Data is corrupted)
CUEREG.C  (14679 B)... Failed! (Error on decrunching)
CUEREG.OBJ  (3655 B)... Failed! (Data is corrupted)
CUESUBS.C  (10744 B)... Failed! (Data is corrupted)
CUESUBS.DEF  (1452 B)... Failed! (Data is corrupted)
CUESUBS.DLL  (33077 B)... OK.
CUESUBS.H  (12841 B)... OK.
CUESUBS.LIB  (3584 B)... Failed! (Data is corrupted)
CUESUBS.LRF  (170 B)... Failed! (Data is corrupted)
CUESUBS.MAP  (19524 B)... OK.
CUESUBS.OBJ  (3481 B)... Failed! (Data is corrupted)
CUESUBS.SYM  (2516 B)... OK.
CUESUP.ASM  (49248 B)... Failed! (Error on decrunching)
CUESUP.OBJ  (5357 B)... Failed! (Data is corrupted)
CUESYS.ASM  (8003 B)... Failed! (Data is corrupted)
CUESYS.DEF  (28 B)... Failed! (Wrong checksum)
CUESYS.INC  (18064 B)... Failed! (Error on decrunching)
CUESYS.MAP  (916 B)... Failed! (Data is corrupted)
CUESYS.OBJ  (882 B)... Failed! (Data is corrupted)
CUESYS.SYM  (244 B)... Failed! (Data is corrupted)
CUESYS.SYS  (1405 B)... Failed! (Data is corrupted)
CUETTY.C  (1967 B)... OK.
CUETTY.OBJ  (573 B)... OK.
CUEUTIL.C  (2624 B)... Failed! (Data is corrupted)
CUEUTIL.OBJ  (696 B)... Failed! (Data is corrupted)
CUEVIO.C  (7116 B)... Failed! (Data is corrupted)
CUEVIO.OBJ  (2226 B)... Failed! (Data is corrupted)
CUEVREG.C  (20393 B)... OK.
CUEVREG.OBJ  (4055 B)... OK.
DEBUG.ASM  (342 B)... Failed! (Data is corrupted)
DEBUG.OBJ  (84 B)... Failed! (Wrong checksum)
READ.ME  (11148 B)... Failed! (Data is corrupted)
TOOLS.INI  (9754 B)... Failed! (Data is corrupted)

So I switched back to an IBM PC and asked the ARC utility to list the archive’s contents:

C:\TMP>ARC L CUE
Name          Length    Date     
============  ========  =========
CUE               2151  27 Feb 89
I don't know how to handle file CUE.C in archive CUE.ARC
I think you need a newer version of ARC.

Well, there were newer versions of ARC, but no, that was not the problem.

The Sad History of ARC Files

In 1986, Phil Katz (“PK”) was a software developer who saw an opportunity to make a faster version of ARC, apparently by taking the original source code and rewriting key portions in assembly language. He formed the company PKware and released his version as two separate programs: PKARC to create and update archives, and PKXARC to extract files from them.

And he didn’t stop there. You may have noticed in my MS-DOS 3.20 example that ARC chose from a variety of storage methods, such as “packing”, “crunching”, and “squeezing”. ARC would choose whichever method was appropriate for a particular file. Katz went a step farther, and with the release of PKARC version 2.0 and PKXARC version 3.4 (both dated 12-15-86), added “squashing”.

Unfortunately, “squashing” created a lot of confusion, because it meant any .ARC archive that contained “squashed” files was unusable by any version of ARC, as well as earlier versions of PKARC and PKXARC. And even if there was precedent for this (if, for example, either of ARC’s “crunching” or “squeezing” methods had been added after ARC’s initial release), the large number of .ARC files being circulated at the time made this change much more problematic.

Compounding matters were questions of whether PKware had violated SEA’s copyrights or trademarks, including the use of SEA’s source code without permission. PKware also started running ads, like the April 1988 PC Tech Journal ad shown below, which reportedly infuriated SEA. A lawsuit ensued, and while a settlement was ultimately reached, PKware simply pivoted to a different archive format (.ZIP) and a new set of utilities (PKZIP and PKUNZIP). The ZIP era was born, and the ARC era gradually came to an end.

There’s a good segment on YouTube from BBS The Documentary by Jason Scott that was filmed around 15 years after the controversy, if you want to learn more about it.

Returning to the ARC of My Story

Getting back to those CUE.ARC archives that I couldn’t decompress, PKXARC version 3.5 recognized all the compression methods being used, including the infamous “squash” method:

C:\TMP>PKXARC -V CUE

PKXARC    FAST!    Archive Extract Utility    Version 3.5    04-27-87
Copyright (c) 1986,1987 PKWARE Inc. All Rights Reserved. PKXARC/h for help

Searching: CUE.ARC

Filename        Length   Method     Size   Ratio    Date      Time    CRC
--------        ------   ------    ------  -----    ----      ----    ---
CUE               2151  Crunched     1071   51%   02-27-89  22:19:02  F48B
CUE.C            20157  Squashed     9802   52%   02-26-89  11:23:30  CFBE
CUE.DEF             35   Stored        35    0%   08-29-88  23:50:22  5050
CUE.DOC          12913  Squashed     6673   49%   04-17-88  01:02:50  814E
CUE.EXE          16463  Crunched    12327   26%   02-26-89  12:10:58  A164
CUE.H            11829  Crunched     5480   54%   02-28-89  21:31:00  9178
CUE.MAP          13942  Squashed     4769   66%   02-26-89  12:10:58  2437
CUE.OBJ           8456  Crunched     6780   20%   02-26-89  12:10:52  2EF3
CUE.SYM           2228  Crunched     1959   13%   02-26-89  12:11:42  895B
CUE.SYS           1405  Crunched      576   60%   01-24-89  12:02:18  F11C
CUECOMM.C         5961  Crunched     3171   47%   02-28-89  10:03:42  F8F4
CUECOMM.OBJ       1710  Crunched     1457   15%   02-28-89  10:04:34  2E67
CUEFIND.C        10264  Crunched     4526   56%   10-27-88  02:05:44  CA6D
CUEFIND.OBJ       3133  Crunched     2561   19%   01-24-89  11:51:14  4BF7
CUEHIST.C         7435  Crunched     3698   51%   10-27-88  00:06:36  F442
CUEHIST.OBJ       2379  Crunched     2054   14%   01-24-89  11:53:58  2760
CUEKBD.C          2958  Crunched     1650   45%   10-25-88  00:02:50  9B67
CUEKBD.OBJ         911  Crunched      774   16%   01-24-89  11:51:30  52D4
CUEKREG.C        15653  Squashed     7305   54%   02-19-89  11:35:06  916C
CUEKREG.OBJ       4108  Crunched     3359   19%   02-19-89  11:54:02  4A91
CUEKSUP.C         5623  Crunched     2529   56%   09-25-88  23:50:28  EFEC
CUEKSUP.OBJ       2010  Crunched     1621   20%   01-24-89  11:53:42  B135
CUEMSE.C          2404  Crunched     1424   41%   09-30-88  13:02:00  8338
CUEMSE.OBJ         672  Crunched      572   15%   01-24-89  11:53:28  7D07
CUEPOP.C         19345  Squashed     8142   58%   10-30-88  12:34:18  1903
CUEPOP.OBJ        5421  Crunched     4229   22%   01-24-89  11:50:48  0F92
CUEPROC.C         8774  Crunched     4574   48%   09-30-88  13:47:30  0662
CUEPROC.OBJ       2675  Crunched     2249   16%   01-24-89  11:54:18  A980
CUEREG.C         14679  Squashed     7116   52%   02-19-89  12:44:28  A1AD
CUEREG.OBJ        3655  Crunched     3010   18%   02-19-89  12:46:06  89D8
CUESUBS.C        10744  Crunched     5235   52%   02-19-89  11:14:36  AABF
CUESUBS.DEF       1452  Crunched      863   41%   02-18-89  04:38:10  4FC1
CUESUBS.DLL      33077  Crunched    24885   25%   02-28-89  22:52:32  84A7
CUESUBS.H        12841  Squashed     6232   52%   02-28-89  22:22:02  8C23
CUESUBS.LIB       3584  Crunched     1294   64%   09-29-88  22:13:40  7338
CUESUBS.LRF        170  Crunched      123   28%   02-18-89  03:51:42  89E8
CUESUBS.MAP      19524  Squashed     6474   67%   02-28-89  22:52:30  F1AC
CUESUBS.OBJ       3481  Crunched     2770   21%   02-19-89  11:16:08  582A
CUESUBS.SYM       2516  Crunched     2256   11%   02-28-89  22:52:36  F010
CUESUP.ASM       49248  Squashed    20230   59%   02-26-89  11:24:02  113F
CUESUP.OBJ        5357  Crunched     4004   26%   02-26-89  12:11:02  8264
CUESYS.ASM        8003  Crunched     4209   48%   10-24-88  22:41:00  4071
CUESYS.DEF          28   Stored        28    0%   08-07-88  02:20:28  85B4
CUESYS.INC       18064  Squashed     9382   49%   08-19-88  18:14:04  3363
CUESYS.MAP         916  Crunched      441   52%   01-24-89  12:02:18  1852
CUESYS.OBJ         882  Crunched      771   13%   01-24-89  12:02:14  1C38
CUESYS.SYM         244  Crunched      186   24%   01-24-89  12:02:20  5A34
CUESYS.SYS        1405  Crunched      576   60%   01-24-89  12:02:18  F11C
CUETTY.C          1967  Crunched     1068   46%   02-28-89  21:27:00  65DD
CUETTY.OBJ         573  Crunched      469   19%   02-28-89  21:46:04  EC7A
CUEUTIL.C         2624  Crunched     1504   43%   10-27-88  02:18:58  022A
CUEUTIL.OBJ        696  Crunched      606   13%   01-24-89  11:54:44  476A
CUEVIO.C          7116  Crunched     3699   49%   10-27-88  15:15:54  2D88
CUEVIO.OBJ        2226  Crunched     1772   21%   01-24-89  11:51:46  4FBF
CUEVREG.C        20393  Squashed     8842   57%   02-28-89  22:51:14  473A
CUEVREG.OBJ       4055  Crunched     3097   24%   02-28-89  22:52:18  1572
DEBUG.ASM          342  Crunched      270   22%   10-25-88  00:16:26  E534
DEBUG.OBJ           84   Stored        84    0%   01-24-89  11:48:44  9440
READ.ME          11148  Crunched     5951   47%   01-24-89  17:09:06  BA31
TOOLS.INI         9754  Crunched     4356   56%   02-25-89  11:36:32  E566
-----           ------             ------  -----
0060            441863             237170   47%

However, neither PKXARC 3.5 nor any other version I tried could extract all the files; an “archive integrity” test using -t reported the same failures, and it didn’t seem to matter if the files were “squashed”, “crunched”, or just “stored”:

C:\TMP>PKXARC -T CUE

PKXARC    FAST!    Archive Extract Utility    Version 3.5    04-27-87
Copyright (c) 1986,1987 PKWARE Inc. All Rights Reserved. PKXARC/h for help

Searching: CUE.ARC
Testing: CUE           Ok
Testing: CUE.C         Warning!  file CUE.C fails CRC check.
Testing: CUE.DEF       Warning!  file CUE.DEF fails CRC check.
Testing: CUE.DOC       Warning!  file CUE.DOC fails CRC check.
Testing: CUE.EXE       Warning!  file CUE.EXE fails CRC check.
Testing: CUE.H         Ok
Testing: CUE.MAP       Warning!  file CUE.MAP fails CRC check.
Testing: CUE.OBJ       Warning!  file CUE.OBJ fails CRC check.
Testing: CUE.SYM       Warning!  file CUE.SYM fails CRC check.
Testing: CUE.SYS       Warning!  file CUE.SYS fails CRC check.
Testing: CUECOMM.C     Ok
Testing: CUECOMM.OBJ   Ok
Testing: CUEFIND.C     Warning!  file CUEFIND.C fails CRC check.
Testing: CUEFIND.OBJ   Warning!  file CUEFIND.OBJ fails CRC check.
Testing: CUEHIST.C     Warning!  file CUEHIST.C fails CRC check.
Testing: CUEHIST.OBJ   Warning!  file CUEHIST.OBJ fails CRC check.
Testing: CUEKBD.C      Warning!  file CUEKBD.C fails CRC check.
Testing: CUEKBD.OBJ    Warning!  file CUEKBD.OBJ fails CRC check.
Testing: CUEKREG.C     Warning!  file CUEKREG.C fails CRC check.
Testing: CUEKREG.OBJ   Warning!  file CUEKREG.OBJ fails CRC check.
Testing: CUEKSUP.C     Warning!  file CUEKSUP.C fails CRC check.
Testing: CUEKSUP.OBJ   Warning!  file CUEKSUP.OBJ fails CRC check.
Testing: CUEMSE.C      Warning!  file CUEMSE.C fails CRC check.
Testing: CUEMSE.OBJ    Warning!  file CUEMSE.OBJ fails CRC check.
Testing: CUEPOP.C      Warning!  file CUEPOP.C fails CRC check.
Testing: CUEPOP.OBJ    Warning!  file CUEPOP.OBJ fails CRC check.
Testing: CUEPROC.C     Warning!  file CUEPROC.C fails CRC check.
Testing: CUEPROC.OBJ   Warning!  file CUEPROC.OBJ fails CRC check.
Testing: CUEREG.C      Warning!  file CUEREG.C fails CRC check.
Testing: CUEREG.OBJ    Warning!  file CUEREG.OBJ fails CRC check.
Testing: CUESUBS.C     Warning!  file CUESUBS.C fails CRC check.
Testing: CUESUBS.DEF   Warning!  file CUESUBS.DEF fails CRC check.
Testing: CUESUBS.DLL   Ok
Testing: CUESUBS.H     Ok
Testing: CUESUBS.LIB   Warning!  file CUESUBS.LIB fails CRC check.
Testing: CUESUBS.LRF   Warning!  file CUESUBS.LRF fails CRC check.
Testing: CUESUBS.MAP   Ok
Testing: CUESUBS.OBJ   Warning!  file CUESUBS.OBJ fails CRC check.
Testing: CUESUBS.SYM   Ok
Testing: CUESUP.ASM    Warning!  file CUESUP.ASM fails CRC check.
Testing: CUESUP.OBJ    Warning!  file CUESUP.OBJ fails CRC check.
Testing: CUESYS.ASM    Warning!  file CUESYS.ASM fails CRC check.
Testing: CUESYS.DEF    Warning!  file CUESYS.DEF fails CRC check.
Testing: CUESYS.INC    Warning!  file CUESYS.INC fails CRC check.
Testing: CUESYS.MAP    Warning!  file CUESYS.MAP fails CRC check.
Testing: CUESYS.OBJ    Warning!  file CUESYS.OBJ fails CRC check.
Testing: CUESYS.SYM    Warning!  file CUESYS.SYM fails CRC check.
Testing: CUESYS.SYS    Warning!  file CUESYS.SYS fails CRC check.
Testing: CUETTY.C      Ok
Testing: CUETTY.OBJ    Ok
Testing: CUEUTIL.C     Warning!  file CUEUTIL.C fails CRC check.
Testing: CUEUTIL.OBJ   Warning!  file CUEUTIL.OBJ fails CRC check.
Testing: CUEVIO.C      Warning!  file CUEVIO.C fails CRC check.
Testing: CUEVIO.OBJ    Warning!  file CUEVIO.OBJ fails CRC check.
Testing: CUEVREG.C     Ok
Testing: CUEVREG.OBJ   Ok
Testing: DEBUG.ASM     Warning!  file DEBUG.ASM fails CRC check.
Testing: DEBUG.OBJ     Warning!  file DEBUG.OBJ fails CRC check.
Testing: READ.ME       Warning!  file READ.ME fails CRC check.
Testing: TOOLS.INI     Warning!  file TOOLS.INI fails CRC check.

I could chalk up the errors in one CUE.ARC file to possible disk corruption, but I had three different CUE.ARC archives, made at different times, and stored on three different diskettes. Why would they all be plagued by similar decompression errors?

Not Corrupted, Just “Garbled”

After more digging, I found a set of unarchived files that had timestamps similar to those in the “corrupted” archive, and when I looked at the first two files in the archive:

Testing: CUE           Ok
Testing: CUE.C         Warning!  file CUE.C fails CRC check.

the unarchived copy of CUE was identical to the archived copy, and the unarchived copy of CUE.C was exactly the same size, so it was probably also identical. So I found and tweaked a UNIX version of ARC, and then I used that to create a “good” .ARC with just those two files.

Then I ran ARC and watched it decode.

Here’s the section containing the header for CUE.C in the “good” archive:

00000440  47 87 23 04 5c 9d 2e 18  c1 2a 2a 00 1a 09 43 55  |G.#.\....**...CU|
00000450  45 2e 43 00 25 25 25 25  25 25 25 4a 26 00 00 9c  |E.C.%%%%%%%J&...|
00000460  12 ec 5a be cf bd 4e 00  00 2f 54 80 00 31 a4 4a  |..Z...N../T..1.J|

The file header began at 0x44C with marker byte 0x1A, followed by “squashed” compression type 0x09; the name of the file (“CUE.C”); the compressed file size (0x264A); date, time, and CRC words; the uncompressed file size (0x4EBD); and finally the compressed data stream at offset 0x469:

2f 54 80 00 31 a4 4a ...

which corresponded to the first few byte of CUE.C:

00000000  2f 2a 20 20 43 55 45 2e  43 0d 0a 20 2a 20 20 42  |/*  CUE.C.. *  B|
00000010  79 20 4a 65 66 66 20 50  61 72 73 6f 6e 73 20 20  |y Jeff Parsons  |

Now here’s the same section from the “corrupted” archive:

00000440  47 87 23 04 5c 9d 2e 18  c1 2a 2a 00 1a 09 43 55  |G.#.\....**...CU|
00000450  45 2e 43 00 25 25 25 25  25 25 00 4a 26 00 00 5a  |E.C.%%%%%%.J&..Z|
00000460  12 ef 5a be cf bd 4e 00  00 78                    |..Z...N..x      |

The date and time words were different, but both the compressed and uncompressed sizes were the same, and even the CRC values (0xCFBE) were identical. And yet, the compressed data streams were completely different; the “good” stream began with 0x2F, but the “corrupted” stream began with 0x78.

At this point, I stopped debugging and thought for a minute. I had just watched ARC read the compressed data using this function:

    getb_unp(f)
    FILE *f;
    {
        register u_int len;

        if (stdlen) {
                len = (stdlen < MYBUF) ? stdlen : MYBUF;

                len = fread(pinbuf, 1, len, f);

                if (password)
                        codebuf(pinbuf, len);
        
                stdlen -= len;
        } else
                len = 0;
        
        return (len);
    }

and then it hit me: what if I had used a password on some of the files in the archive? That might explain why none of the compressed bytes looked the same. So I took a quick look at codebuf():

    VOID
    codebuf(buf, len)               /* encrypt a buffer */
    reg char       *buf;
    u_int           len;
    {
            reg u_int       i;
            reg char       *pasptr = p;

            for (i = 0; i < len; i++) {
                    if (!*pasptr)
                            pasptr = password;
                    *buf++ ^= *pasptr++;
            }
            p = pasptr;
    }

and all it did was sequentially XOR every byte in the buffer with bytes from the password. So I took the first byte from each compressed stream again (0x2F and 0x78), XOR’ed them, and got 0x54, or capital “W”. I repeated the process until the letters began repeating, and now I had the complete 6-letter password. Every file that had originally reported a CRC error could now be successfully extracted with that password.

I’m still not sure why I would have bothered password-protecting any of the files in the archive, let alone only some of them. ARC will clearly let you do that, but the result is a mess, because any unprotected files will appear corrupt if you supply any password, and any password-protected files will appear corrupt if you don’t supply the right password. And there’s no hint in either case that you should – or should not – supply a password.

Here’s an excerpt from the ARC manual regarding this feature, known as the “Garble” option:

This is not a particularly sophisticated means of encryption, and it is theoretically possible to crack. Still, since it is performed on the packed data, the result should be quite sufficient for casual use.

You can, if you wish, use different passwords for different files in an archive, but we advise against it. If you are going to encrypt an archive, we suggest you use the same password for every file, and give the password whenever you do anything at all with the archive. It is possible to list the entries in an encrypted archive using the “L” and “V” commands without giving the password, but nothing else will work properly.

We advise that you use this option sparingly, if at all. If you should forget or mistype your password, it is highly unlikely that you will ever recover your data.

In retrospect, ARC probably should have had an “encrypted” indicator in each file header, so that it could simply bypass any encrypted files when no password was provided, as well as some means of verifying a compressed stream after unencrypting it (before attempting to decompress it). ARC would usually halt and report a cryptic error when decoding an invalid (“garbled”) data stream, but the error would be unpredictable, with no indication of what the real problem was – not a very user-friendly result.

Anyway, to celebrate, I’ve added the entire contents of that weird CUE.ARC to a new Cue repository, so that everyone can enjoy all that crusty, now-useless code from 1988. Cue was a popular in-house OS/2 utility back in the day, but like so many other tools we used to use at Microsoft (Z, WZMAIL, etc), it’s faded into oblivion.

Is the Living Computer Museum Dead?

Thu, 16 Feb 2023 11:00:00 +0000

I first visited Paul Allen’s Living Computer Museum in October 2013. It offered a unique museum experience, combining traditional displays and plaques with interactive exhibits and vintage computers that allowed you to run a variety of old software–and even write your own.

In 2012, when the museum first opened to the public, here’s what Paul Allen wrote on the LCM website:

Note one sentence in particular:

The Living Computer Museum also fulfills my hope that the achievements of early computer engineers aren’t lost to time.

It’s unfortunate that Paul Allen, after investing so much time, energy, and money in the Living Computer Museum and its people – not to mention his express hope that efforts like his would not be “lost to time” – didn’t ensure that the museum would continue after his death.

It makes sense for some of Paul Allen’s acquisitions, like his recently auctioned art collection, to find their way into new hands after he’s gone. Items like artwork are always changing hands.

But LCM was fundamentally different. It also involved a lot of acquisitions, but as the Living Computer Museum, it became something greater than the sum of its parts. It was Paul Allen’s personal creation, and a reflection not only of the legacy of the entire computer industry, but also of his own legacy.

The LCM website hasn’t changed much over the last 3 years, and it continues to say the museum “is closed for now,” with no indication of what, if anything, Vulcan decided to do when the first 18 months came and went. And we are now fast approaching the end of another 18 months since the museum closed.

When will someone turn the lights back on at LCM?

P.S. I took hundreds of photos at the Living Computer Museum during my visits over the years, and future posts will feature some of those photos, focusing on all the good work the museum used to do.

Also, I encourage you to leaf through LCM’s Engineering Blog, before someone decides to power that down as well.

Update (February 17, 2023)

Several people noted – and I should have mentioned – that there is still remote access to a number of systems at LCM. In fact, after more than two years of total silence, LCM sent this email to former remote systems users in October 2022:

Hello,

Several years ago we modified how the Remote Systems are accessed via 
the INTERNET.  Connections originally were done directly via TELNET
and some of the systems lived wildly on the wild INTERNET.

Currently all Remote Systems are accessible via a Secure Shell (ssh)
pass-through server know as 'tty.livingcomputers.org'. 

Examples of ssh clients are:

* Windows:      putty
* MacOS X:      ssh in Terminal.app
* Linux/BSD:    ssh 
* Web Browser:  https://ssh.livingcomputers.org

To reach the Remote Systems, you can use 'ssh menu@tty.livingcomputers.org'
This will present you with a menu system which lists all available hosts and
what they are running.  Currently there are 17 Remote Systems online with 
the majority running on real vintage hardware while 4 are operated as hybrid 
or full emulation.

When you make a selection in the menu interface information regarding direct
access to that host, as well as guest login access, will be displayed.  If you
have a login on that particular host, you can log on or use the guest account.
Note, if you've forgotten your login/password, please reply to get it reset.

A user contributed WIKI can be found at https://wiki.livingcomputers.org 
Here you'll find Remote Systems pictures, details, manuals, survival guides
and coding examples.  If you have some coding examples or additions to the
survival guides, please let us know.

Thank you for continuing to use the Remote Systems at Living Computers!

Stephen Jones

The focus of my post was the entire museum and all the in-person interactive programs that it used to offer, but it is nice to know that there are still some beating hearts and spinning disks in the bowels of the building, so perhaps all hope is not lost.

The Adventure of the Mysterious Mail Files

Mon, 30 Jan 2023 12:00:00 +0000

I’ve recently been sifting through many boxes of loose diskettes. Any disks with personal information are being copied and then destroyed, while any “commercial” disks are also being copied and then put in a box for resale or donation. Hopefully later this year, my house will finally be free of ancient disk clutter.

Anyway, last week, I came across a few 10-diskette boxes containing disks labelled “MAIL1.1”, “MAIL1.2”, etc. Not very illuminating. So I made copies of them all and then looked at their contents; here’s what was on the first couple of disks:

 Volume in drive A has no label
 Directory of A:\

MAIL1    1     1442584   1-27-94  11:58a
        1 file(s)    1442584 bytes
                       14848 bytes free

 Volume in drive A has no label
 Directory of A:\

MAIL1    2     1442584   1-27-94  11:58a
        1 file(s)    1442584 bytes
                       14848 bytes free

and except for one string near the beginning of the first file:

00000090  45 6e 67 6c 69 73 68 20  28 41 6d 65 72 69 63 61  |English (America|
000000a0  6e 29 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |n)..............|

the rest of the files contained no human-readable text.

There were 18 diskettes altogether, and fortunately, there was a clue on disk #14:

 Volume in drive A has no label
 Directory of A:\

MAIL2    A      265513   1-27-94  12:11p
MAIL3    MMF    408321  10-18-93   5:34p
        2 file(s)     673834 bytes
                      783360 bytes free

At last it was clear that these files were pieces of Microsoft Mail Files or MMFs, and while MAIL3.MMF had been small enough to fit on a single diskette, all the other MMF files had been chopped up into diskette-sized pieces, using some sort of “splitting” utility that I had probably written specifically to make my own email backups.

It was easy enough to recombine the pieces and recreate four presumably complete MMF files, but now the question was how to read them.

My first thought was OUTLOOK, since I already had a copy of it on my MacBook; however, I couldn’t find any options for importing MMF files. I gradually came to the conclusion that the simplest solution would be to use the Inbox (Windows Messaging) application that came with Windows 95, which would allow me to create a PST file, import the MMF files, and then I could move the PST file to my MacBook and open it with OUTLOOK.

Well, that may have seemed like the simplest solution, but it was anything but simple….

Running Windows 95

I had upgraded to an M1 (Apple Silicon) MacBook a few months ago, so it turned out that getting Windows 95 to run in a virtual machine on my MacBook was harder than I’d expected. In “the old days”, with an Intel MacBook, I could (and did) run Windows 95 in a VM using VMware Fusion, Parallels, and VirtualBox. However, with an M1 MacBook, none of those were options anymore, because they all require an Intel processor to “virtualize” an x86 environment; they could not actually “emulate” one.

UPDATE: VirtualBox may eventually become a viable solution, because Oracle recently released a V7 beta that supports x86 emulation on Apple Silicon; unfortunately, the beta crashes a lot, so I’m holding off until it becomes more stable.

The only more-or-less stable “emulation” option appeared to be QEMU, and I chose the version of QEMU bundled with UTM, since UTM includes some nice UI enhancements that make it easier to manage QEMU-based VMs.

Using QEMU, Windows 95 and the “Inbox” (Windows Messaging) application were easy enough to setup, and Windows Messaging seemed willing to import my MMF files. But anticipation quickly turned to disappointment when it prompted me for a password. I had vague recollections of some passwords that I might have used over 30 years ago, but nothing I tried worked.

I knew that Microsoft’s post-MMF storage solution – PST files – had had weak password protection, because several years ago, I had unearthed some password-protected PST files, and it hadn’t been hard to find a PST tool online that could recreate working passwords. The tool seemed unable to recover the original password, but it could apparently generate any number of alternate strings that worked just as well as the original password.

Unfortunately, a quick online search for a similar MMF password recovery tool turned up absolutely nothing. In fact, I could barely find any information at all about MMF files, let alone how to recover a lost MMF password. I did find some references to an ADMIN.EXE tool as part of Microsoft Mail for PC Networks that might have offered some recovery options, but did I really want to set up my own Microsoft Mail “postoffice” server to find out? I didn’t think so.

And there was a potentially shorter path to success. Every time the “Import” command displayed the following MessageBox:

it clearly had some idea (if it was comparing password hashes), and possibly even an exact idea (if it was comparing plain-text passwords), of what the original password was. All I needed to do was to fire up a debugger and find the exact spot in memory where that check was being performed.

The game was afoot!

Debugging Windows 95

I still find that the easiest way to debug software on Windows 95 is with WDEB386.EXE, the beloved kernel debugger that I and my co-workers used to debug thousands of issues during the development of Windows 95. And I still had a small collection of symbol (SYM) files to make debugging easier, including KERNEL32.SYM, USER32.SYM, and GDI32.SYM.

So the debugging process seemed simple enough: set breakpoints on a few Win32 Dialog Box APIs, like DialogBoxParamA, then bring up the MMF password dialog, make a note of the app’s “dialog procedure” address, and then watch what happens when the “OK” button is pressed.

The app immediately called GetDlgItemTextA (no big surprise) to get the string I had just typed. At that point, debugging should have been a simple exercise of using “data” breakpoints to watch the code read that string (as well as any copies it made of the string), catching the code comparing the string to something else, and then seeing what that “something else” was.

And that’s when QEMU let me down. For whatever reason, whenever the kernel debugger’s data read breakpoint should have fired, QEMU simply hung.

So I gave up trying to do everything on my M1 MacBook, and fired up an old Windows 95 VM using VMware on an Intel Mac Mini, and repeated the entire process. And then VMware let me down. It seemed that data breakpoints simply did not work in VMware; the kernel debugger (WDEB386.EXE) could happily set the breakpoints, but they would never fire.

So, OK, I had v6.1 of VirtualBox on the Intel Mac Mini, so I decided to use that instead. Well, that was even worse: every time I tried to access a symbol, like GetDlgItemTextA, the kernel debugger would crash:

1##u getdlgitemtexta
Trap 6 - Invalid Opcode Exception - In Debugger
eax=b0000000 ebx=c13a6f9b ecx=000000fe edx=00340104 esi=00005fe6 edi=c1596d9d
eip=00000530 esp=00006a0a ebp=c13c4303 iopl=3 RF -- -- nv up di NG nz AC PE nc
cs=0058 ss=0060 ds=0060 es=0060 fs=0030 gs=0030  cr2=7fe95000  cr3=004eb000
0058:00000530 ffe8           jmp     eax

This was getting frustrating. In the end, I resorted to using two VMs side-by-side: VirtualBox with its built-in debugger to debug one machine, and QEMU running the Windows 95 kernel debugger in another machine. I would look up symbols in the QEMU machine, and then use the corresponding linear addresses in the VirtualBox machine.

What I Finally Learned

The Windows Messaging application, EXCHNG32.EXE, uses a DLL called the “MMF Migration Library” (MMFMIG32.DLL) to handle all things MMF-related. Turning on the Windows 95 kernel debugger’s segment load notifications revealed where the DLL was loaded:

MMFMIG32!MMFMIG32!undefined code(0001)=%7f801000 len 00031800
MMFMIG32!MMFMIG32!undefined data(0002)=%7f833000 len 00007600
MMFMIG32!MMFMIG32!undefined data(0003)=%7f83b000 len 00001600
MMFMIG32!MMFMIG32!undefined data(0004)=%7f83d000 len 00000200
MMFMIG32!MMFMIG32!undefined data(0005)=%7f83e000 len 00003800
MMFMIG32!MMFMIG32!undefined data(0006)=%7f842000 len 00003400

I also created a disassembled copy of the MMF Migration Library to make debugging a bit easier.

After numerous false starts, I eventually got the process down to a few steps. First, I set an INT3 breakpoint on GetDlgItemTextA (“bp %bff61657”), clicked “OK” in the password dialog, and when the breakpoint was hit, set a new INT3 breakpoint in MMFMIG32.DLL, inside 7f810181, at 7f8101f3:

eax=7f8367e4 ebx=7f8367d8 ecx=00000008 edx=00000008 esi=00000000 edi=00000008
eip=7f8101f3 esp=0063f260 ebp=0063f270 iopl=0 rf nv up ei pl nz na pe cy
cs=0137 ds=013f es=013f fs=1a8f gs=0000 ss=013f               eflags=00010203
0137:7f8101f3 3b cf                   cmp ecx, edi

At this point, EDI was the length of the typed password, and ECX was the length of the stored password. These lengths include room for a terminator, so in the above example, since EDI contained 8, a 7-character password was expected. If the lengths didn’t match, I would start over with a password guess that was the same length.

Ultimately, I finally found where the MMF’s internal password was being extracted, so all I had to do was set a write breakpoint on 7f8367e4 (“ba w 1 %7f8367e4”). It would stop on a REP MOVSD instruction, and after letting the instruction finish, I dumped the memory at 7f8367e4. For example, here’s what the 7-character password for one of my MMF files looked like:

%7f8367e4: 56 45 52 54 49 47 4f 00-00 00 00 00 00 00 00 00  VERTIGO.........

The code in MMFMIG32.DLL that actually deciphers the password stored in the MMF is located at 7f8128e1. Here’s a listing:

sub_7F8128E1    proc near

        arg_0   = dword ptr  8
        arg_4   = dword ptr  0Ch
        arg_8   = dword ptr  10h
        arg_C   = dword ptr  14h

        push    ebp
        mov     ebp, esp
        push    ebx
        push    esi
        push    edi
        mov     edi, [ebp+arg_8]
        mov     eax, edi
        dec     edi
        test    eax, eax
        jz      short loc_7F81292D
        mov     eax, [ebp+arg_0]
        mov     esi, [ebp+arg_4]
        mov     edx, [ebp+arg_C]

loc_7F8128FA:
        mov     cl, [eax]
        inc     eax
        add     cl, dl
        movzx   ecx, cl
        mov     bl, byte_7F835AE8[ecx]
        mov     cl, dh
        add     bl, cl
        movzx   ebx, bl
        mov     bl, byte_7F835CE8[ebx]
        sub     bl, cl
        movzx   ecx, bl
        mov     cl, byte_7F835BE8[ecx]
        sub     cl, dl
        inc     edx
        mov     [esi], cl
        inc     esi
        mov     ecx, edi
        dec     edi
        test    ecx, ecx
        jnz     short loc_7F8128FA

loc_7F81292D:
        pop     edi
        pop     esi
        pop     ebx
        pop     ebp
        retn    10h
sub_7F8128E1    endp

When it came up with the password VERTIGO, one of the inputs was this data:

%00b84a8c: 9d f5 54 33 1d 9d 87 8e-18 f3 05 ed 2c 38 bf fb  ..T3........,8..
%00b84a9c: ad f3 2f 12 da 46 6c 24-76 79 d7 5f 67 2d aa 43  ../..Fl$vy._g-.C

which corresponded to this section of the MMF:

00004200  9d f5 54 33 1d 9d 87 8e  18 f3 05 ed 2c 38 bf fb  |..T3........,8..|
00004210  ad f3 2f 12 da 46 6c 24  76 79 d7 5f 67 2d aa 43  |../..Fl$vy._g-.C|

However, the code uses multiple inputs, so I don’t think you can decipher the original password from that section alone.

In any case, once I had my passwords, I was done debugging. If anyone else wants to dig into this more and write a general-purpose MMF password recovery tool, there’s absolutely no doubt it can be done, but I also have absolutely no interest in doing that myself.

Besides, I have some old email to catch up on!