Category Archives: Microsoft

PC DOS 1.0, But Not Quite

Posted on May 26, 2017 by Michal Necasek

Last week a most interesting image of a 160K disk arrived at the OS/2 Museum. The files on the disk image are rather old. When the disk boots up (not trivial, see below), the following message appears: Astute readers will … Continue reading →

Posted in DOS, IBM, Microsoft, PC history, Pre-release | 40 Comments

How the PC Industry Screws Things Up

Posted on April 7, 2017 by Michal Necasek

I was recently involved in investigating a problem that turns out to be a complete SNAFU which nicely illustrates the chaos that is the PC platform. It’s about the NX/XD bit. Let’s start with a bit of history. It turns … Continue reading →

Posted in AMD, Intel, Microsoft | 32 Comments

OS/2 2.0 at 25

Posted on March 31, 2017 by Michal Necasek

Twenty-five years ago, on March 31st, 1992, IBM released OS/2 2.0, the first mass-market 32-bit PC operating system. The road to OS/2 2.0 was quite long and winding, and the OS was a proud member of the vaporware club (just like, … Continue reading →

Posted in 386, IBM, Microsoft, OS/2 | 32 Comments

There’s More to the 286 XENIX Story

Posted on March 22, 2017 by Michal Necasek

It turns out that there is a rather interesting story behind the 286 XENIX incompatibility with 386 and later processors. Here’s roughly what happened in chronological order. In 1982, Intel released the iAPX 286 processor, later known as the 80286 or simply 286. This … Continue reading →

Posted in 286, 386, Intel, Microsoft | 39 Comments

Oldest Surviving 386 PC OS?

Posted on March 9, 2017 by Michal Necasek

Four years ago, the Xenix 2.2.3 mystery cropped up (twice). The issue has been revisited and thanks to Michael Casadevall, an enthusiastic reader, came to a happy conclusion: 386 Xenix version 2.2.3 was finalized in late June 1988 (the newest … Continue reading →

Posted in 386, Microsoft, SCO, UNIX, Xenix | 21 Comments

IBM XENIX 1.0 Incompatibility Details

Posted on February 7, 2017 by Michal Necasek

Some time ago I wrote about IBM PC XENIX 1.0 and why it won’t work on 386 and later processors. Thanks to a kind reader, I’ve been able to analyze the object files used to link the kernel, and I believe … Continue reading →

Posted in 286, 386, Microsoft, Xenix | 19 Comments

Updating Windows

Posted on May 27, 2016 by Michal Necasek

Updating older (but still supported) Windows versions can be a tedious tasks. Not only for humans but also for computers. Searching for updates for half an hour every time with the CPU going at full tilt must be a not … Continue reading →

Posted in Microsoft, Windows | 16 Comments

Playing Football

Posted on February 19, 2016 by Michal Necasek

The Super Bowl is long over and it’s time to look at different kind of football. In Winter 1986/1987, Microsoft initiated a small skunkworks project called “Football”. The objective was to take “Sizzle”, a development branch of proto-OS/2 that would eventually … Continue reading →

Posted in 386, IBM, Microsoft, OS/2, PC history | 17 Comments

Before OS/2 Was OS/2

Posted on February 5, 2016 by Michal Necasek

After almost 30 years, several disks with ancient builds of OS/2 surfaced. In this context, “ancient” means older than the May 1987 release of the first MS OS/2 SDK. In fact these disks are so old that the one thing … Continue reading →

Posted in IBM, Microsoft, OS/2, PC history, Undocumented | 36 Comments

MS C 4.0 Documentation Added

Posted on November 27, 2015 by Michal Necasek

Another library expansion. This time it’s Microsoft C 4.0 documentation (1986)—because it’s not available online, is not easy to find offline, and because Jeff asked for it. MS C 4.0 was an early Microsoft compiler, implementing first glimpses of the not-yet finalized … Continue reading →

Posted in C, Documentation, DOS, Microsoft | 6 Comments