Category Archives: Microsoft

More MS OS/2 2.0

Posted on June 30, 2024 by Michal Necasek

Over the last few weeks, two “new” pre-releases of OS/2 2.0 have been found in ancient warez archives. The first is OS/2 2.0 build 6.64, released in early April 1990: In general, this build is not substantially different from the … Continue reading →

Posted in IBM, Microsoft, OS/2, Pre-release | 5 Comments

Who Knew What When

Posted on June 28, 2024 by Michal Necasek

When Microsoft released the unique early beta build of Multitasking DOS 4, I quickly found out that it does not run in VirtualBox: This was a bit of a surprise, because the more-or-less released versions of Multitasking DOS 4 from … Continue reading →

Posted in 286, DOS, IBM, Microsoft, PC architecture, PC history, VirtualBox | 26 Comments

Learn Something Old Every Day, Part XII: Strange File Resizing on DOS

Posted on June 7, 2024 by Michal Necasek

Someone recently asked an interesting question: Why do Microsoft C and compatible DOS compilers have no truncate() and/or ftruncate() library functions? And how does one resize files on DOS? OK, that’s actually two questions. The first one is easy enough … Continue reading →

Posted in Computing History, CP/M, Development, Documentation, DOS, Microsoft | 27 Comments

The Future That Never Was

Posted on March 4, 2024 by Michal Necasek

Microsoft OS/2 2.0 SDK Pre-Release 2, June 1990 In 1990, the strategic PC operating system of Microsoft and IBM was not DOS, not Windows, but OS/2. The first 16-bit OS/2 was initially released in 1987 with a reduced feature set, … Continue reading →

Posted in 386, IBM, LAN Manager, Microsoft, OS/2, PC history, Pre-release | 76 Comments

From the Annals of Preprocessor Hackery

Posted on October 22, 2023 by Michal Necasek

Over the last few days I’ve been slowly attacking the source code for 386MAX, trying to build the entire product. One of the many problems I ran into turned out to be quite interesting. There are several (16-bit) Windows components … Continue reading →

Posted in 386MAX, C, Development, Microsoft | 25 Comments

VDS: Borne out of Necessity

Posted on October 5, 2023 by Michal Necasek

In July 1990, Microsoft released a specification for Virtual DMA Services, or VDS. This happened soon after the release of Windows 3.0, one of the first (though not the first) providers of VDS. The VDS specification was designed for writers … Continue reading →

Posted in 386, Documentation, Microsoft, PC history, Windows | 10 Comments

This Code Smells of Desperation

Posted on August 5, 2023 by Michal Necasek

A few weeks ago I had the questionable pleasure of diving into the math exception handler of WIN87EM.DLL, the Windows 3.1 math emulator and FPU support library. Actually WIN87EM.DLL appears to have been first shipped with Windows 3.0, and the … Continue reading →

Posted in Bugs, Microsoft, PC architecture, x87 | 19 Comments

Retro-Porting to NT 3.1

Posted on July 26, 2023 by Michal Necasek

In another useless project, I decided to find out why even trivial programs created with the Open Watcom compiler refuse to run on Windows NT 3.1. Attempting to start an executable failed with foo.exe is not a valid Windows NT … Continue reading →

Posted in Development, Microsoft, NT, Watcom | 12 Comments

Retro-Porting to OS/2 1.0

Posted on July 20, 2023 by Michal Necasek

A few weeks ago I embarked on a somewhat crazy side project: Make the Open Watcom debugger work on OS/2 1.0. This project was not entirely successful, but I learned a couple of things along the way. The Open Watcom … Continue reading →

Posted in Development, IBM, Microsoft, OS/2, Watcom | 10 Comments

A House of Cards

Posted on December 30, 2022 by Michal Necasek

As one step in the development of the Windows 3.x/2.x display driver, I needed to replace a BIOS INT 10h call to set the video mode with a “native” mode set code going directly to the (virtual) hardware registers. One … Continue reading →

Posted in Bugs, Development, Microsoft, Windows | 49 Comments