Author Archives: Michal Necasek

OS/2 2.0, Xmas ’91 Edition

Posted on April 26, 2017 by Michal Necasek

After reviewing the OS/2 2.0 level 6.605 pre-release, another re-discovery is the “Limited Availability” (LA) level 6.177 from December 1991. This was the last OS/2 2.0 pre-release of 1991 and also the last one using the 6.1xx numbering; the next pre-release was … Continue reading →

Posted in 386, IBM, OS/2, PC history | 18 Comments

CF/IDE/SCSI Benchmark Update

Posted on April 22, 2017 by Michal Necasek

To see how the CF-to-IDE-to-SCSI solution really performs, I tried it in a slightly faster system. GA-586HX motherboard (Intel 430HX chipset), AMD K5-133 processor, and PCI SCSI HBAs. The first tested configuration was using a Tekram DC-390 HBA. Sysinfo showed 8.7 … Continue reading →

Posted in CompactFlash, SCSI, Storage | 12 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 | 37 Comments

OS/2 2.0, Summer ’91 Edition

Posted on April 5, 2017 by Michal Necasek

In a fascinating example of poor timing, disk images of OS/2 2.0 pre-release level 6.605 from July/September 1991 were missing for over 25 years, only to show up literally one day after after the 25th anniversary of the OS/2 2.0 release … Continue reading →

Posted in 386, IBM, OS/2, PC history | 37 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 | 34 Comments

Something New Every Day…

Posted on March 26, 2017 by Michal Necasek

Apparently in 1990, Intel still sold complete systems, and they were PC compatible at that point. And perhaps not surprisingly, Intel also OEMed MS OS/2 1.21: And there was this cute ASCII-art logo: There very little customization that Intel did, … Continue reading →

Posted in Intel, OS/2 | 14 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 | 43 Comments

PCI Corner Case

Posted on March 20, 2017 by Michal Necasek

Last weekend I had the pleasure of debugging a curious case of older PCI configuration code (circa 2005) failing on newer (post-2010) hardware. The code was well tested on many 1990s and 2000s PCs (and some non-PCs) with PCI/AGP/PCIe and never … Continue reading →

Posted in Bugs, Intel, PCI | 11 Comments

IBM XENIX: Two Steps Forward

Posted on March 16, 2017 by Michal Necasek

There are reasons to revisit an old topic. Very old, considering that IBM Xenix 1.0 was released in 1984, well over 30 years ago. To recap, this version of Xenix is unique in that it runs only on 286 processors. It … Continue reading →

Posted in 286, IBM, VirtualBox, Xenix | 23 Comments

Tales From the Xenix Crypt

Posted on March 13, 2017 by Michal Necasek

What does Xenix have to do with the Enigma machine? Perhaps surprisingly, there is a clear connection… When reconstructing 386 Xenix 2.2.3, the libmdep.a library proved to be a particularly tough nut to crack. That is because it’s one of … Continue reading →

Posted in SCO, Software Hacks, Xenix | 17 Comments