OS/2 Museum

I have an old, circa 1994 IBM ThinkPad 750C (with a 33MHz Intel 486SL processor) which used to work but now refuses to boot with error I9990303.

When I was researching the mess related to strange and poorly documented CPUID bits in the Athlon MP and XP processors, I had to swap a lot of CPUs.

A reader pointed at the 1992 game Comanche: Maximum Overkill by NovaLogic as a possible unreal mode user—since the original game release was known to be problematic.

This is a kind of knowledge base article which resulted from attempts to understand exactly how memory management works in 16-bit Windows.

Last week I had another run-in with VGA emulation, and like last time, the cause was very likely the generally woefully inadequate VGA documentation.

Some time ago I embarked on a minor retro development project related to this post.

Last week I spent far too much time trying to get my Windows 11 machine to talk to an antique Tyan SMDC (Server Management Daughter Card) IPMI module over the network.

Not too long ago I had a need and an opportunity to re-acquaint myself with the mechanism used for software emulation of the 8087 FPU on 8086/8088 machines.

Quite a while ago, I acquired a dual-socket (Socket 462 aka Socket A) board for the Athlon MP, AMD’s first entry into the multi-processor/multi-socket market.

Yesterday I had the opportunity to test a recently acquired Athlon 1200 CPU (Thunderbird core, ceramic PGA package).

This post ended up being much longer than originally intended because halfway into writing it, I found that 286 and later CPUs don’t behave the way I had assumed they would… While investigating a bug related to a program using floating-point math on a 386…

Some time ago I ran into a bug that had been dormant for some time.

The memory management in DOS is simple, but that simplicity may be deceptive.

There are situations where software is available only in the form of a floppy image.

Spurred by a discussion about Polish keyboard layouts, I tried to find more about the history of Czech keyboard layouts.

It is fair to say that Novell struggled with moving from the IPX protocol to TCP/IP.

While working on a hobby project, I set up an OS/2 MCP2 (Convenience Package 2 for OS/2 Warp 4) virtual machine with a debug kernel and an expectation that I’d reboot the VM a lot.

I have recently explored (again) the possibility of writing a high-res display driver for virtualized OS/2.

Large companies like IBM, Microsoft, or Novell typically had a well defined process for releasing software on floppies.

I was recently made aware of something that I had noticed before, but never paid much attention to.

Investigating the rather odd behavior of the Microsoft OS/2 1.21 disk driver led me to Compaq and their EXTDISK.SYS driver.