Author Archives: Michal Necasek

Rich Heimlich’s Patch Set Overview

Posted on June 9, 2017 by Michal Necasek

Resurrected from the depths of the Internet, here comes an interesting and useful historical resource.  In 1994 and 1995, Rich Heimlich published several iterations of his “patch set overview” covering mainstream wavetable sound cards, daughterboards, and modules (“mainstream” being defined … Continue reading →

Posted in PC history, Sound, Wave Blaster | 33 Comments

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 | 47 Comments

How Many Gravis UltraSounds?

Posted on May 20, 2017 by Michal Necasek

The question came up a while ago. Just how commercially unsuccessful was the Gravis UltraSound? There appears to be no public information about the sales volume of the UltraSound. But now, looking at a sample of 3 (three) classic GUS … Continue reading →

Posted in PC history, Sound, UltraSound | 51 Comments

VME Broken on AMD Ryzen

Posted on May 12, 2017 by Michal Necasek

That’s VME as in Virtual-8086 Mode Enhancements, introduced in the Intel Pentium Processor, and initially documented in the infamous NDA-only Appendix H. Almost immediately since the Ryzen CPUs became available in March 2017, there have been various complaints about problems … Continue reading →

Posted in AMD, Bugs | 36 Comments

SGDT/SIDT Fiction and Reality

Posted on May 4, 2017 by Michal Necasek

PSA: Actual hardware behavior takes precedence over vendor documentation. Or, as they say… trust but verify. A reader recently complained how Intel and AMD do not implement the SGDT and SIDT instructions the same way. AMD documentation states that these … Continue reading →

Posted in 286, 386, AMD, Documentation, Intel | 39 Comments

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 | 16 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