Category Archives: IBM

Learn Something Old Every Day, Part XVI: DOS 4.0 SELECT Is Too Clever

Posted on July 2, 2025 by Michal Necasek

A while ago I discovered an antique pirated copy of IBM DOS 4.00 on 5.25″ media, which was something that was missing in my archive. And by antique I mean from August 1988, when DOS 4.0 was practically brand new. … Continue reading →

Posted in Archiving, DOS, IBM, PC history | 17 Comments

Where Did CP852 Come From Again?

Posted on June 27, 2025 by Michal Necasek

An earlier article explored the history of codepage 852 (Latin-2 PC codepage) in released and pre-release versions of DOS and OS/2. At the time of this writing (June 2025), the earliest OS/2 build with some form of CP852 support including … Continue reading →

Posted in DOS, I18N, IBM, PC history | 25 Comments

Learn Something Old Every Day, Part XV: KEYB Is Half of Keyboard BIOS

Posted on June 16, 2025 by Michal Necasek

Recently I had an opportunity to reacquaint myself with the DOS KEYB utility. KEYB is interesting in that it is designed primarily for international users, but one can also run KEYB US to load KEYB with standard US layout. It … Continue reading →

Posted in BIOS, DOS, IBM, Keyboard | 10 Comments

AI Responses May Include Mistakes

Posted on May 20, 2025 by Michal Necasek

The other day I wanted to look up a specific IBM PS/2 model, a circa 1992 PS/2 Server system. So I punched the model into Google, and got this: That did not look quite right, since the machine I was … Continue reading →

Posted in IBM, PS/2 | 27 Comments

The Other Three

Posted on January 2, 2025 by Michal Necasek

A previous blog post explored the semi-mysterious yet sometimes highly useful DOS APPEND command. Now it’s time to look at its relatives: ASSIGN, JOIN, and SUBST. ASSIGN ASSIGN is the oldest of the bunch. It was written by IBM and … Continue reading →

Posted in DOS, IBM, PC history | 13 Comments

DOS APPEND

Posted on December 20, 2024 by Michal Necasek

For a long time, I couldn’t quite grasp what the DOS APPEND command could possibly be good for. Until I came across a situation which APPEND was made for. When I worked on organizing and building the DOS 2.11 source … Continue reading →

Posted in DOS, IBM | 46 Comments

Programming NetBIOS on OS/2

Posted on October 23, 2024 by Michal Necasek

Recently I spent some time trying to understand a piece of networking code, and it turned out to be far more difficult than it should have been. The code in question is the NetBIOS interface of C-Kermit and was originally … Continue reading →

Posted in Development, Documentation, IBM, Microsoft, Novell, OS/2 | 21 Comments

OS/2 TCPBEUI Name Resolution

Posted on October 8, 2024 by Michal Necasek

Sometimes I have the following problem to deal with: An OS/2 system uses NetBIOS over TCP/IP (aka TCPBEUI) and should communicate with a SMB server (likewise using TCPBEUI) on a different subnet. This does not work on OS/2 out of … Continue reading →

Posted in IBM, Networking, OS/2, TCP/IP | 49 Comments

IBM PC 5150 Model Numbers

Posted on September 24, 2024 by Michal Necasek

Recently I came across a minor mystery—the model numbers of the original IBM PC. For such a pivotal product, there is remarkably little detailed original information from the early days. When IBM started selling the PC, it used two methods … Continue reading →

Posted in IBM, PC hardware, PC history | 27 Comments

OS/2 2.0 Commitments

Posted on September 23, 2024 by Michal Necasek

Last week the OS/2 Museum received a rather interesting donation: a thick spiral bound document titled Third party commitment to IBM’s OS/2 Version 2.0, and labeled IBM COMDEX/SPRING ’92. The binder is a collection of about 250 press releases that … Continue reading →

Posted in IBM, Marketing, OS/2, PC history | 8 Comments