Author Archives: Michal Necasek

SYSENTER, Where Are You?

It has only recently been brought to my attention that Intel’s SYSENTER/SYSEXIT instructions have rather unusual past, and their origin is shrouded in mystery and confusion. One facet of the usage of these instructions is also a little unorthodox. Depending … Continue reading

Posted in Intel, PC history, Undocumented | 5 Comments

Of G-Men and Farmers

There’s an interesting story concerning this Midiman GMan General MIDI sound module. It involves Midiman (better known as M-Audio), the Farmers Insurance Exchange, and also Dream/Atmel, Crystal Semiconductor, and Roland. (Apologies for the beat-up specimen.) The story of course concerns … Continue reading

Posted in Crystal Semi, Dream, Legal, MIDI, Roland, Sound | 20 Comments

Would You Believe It?

The following article was printed in Computer Shopper, June 1992 issue (page 152). Commentary follows. The Big Squeeze Compression Scheme Shatters Storage Logjam Todd Daniel believes he has found a way to revolutionize data storage as we know it. DataFiles/16, … Continue reading

Posted in PC history, PC press | 56 Comments

Brightening Up

A depressingly yellowed Roland CM-64 led me to try retr0bright for the first time. The short story is that despite a few minor missteps, the experiment was a success. Yes, it really does work! Here’s what the CM-64 looked like … Continue reading

Posted in Fixes, Hardware Hacks, Roland | 7 Comments

VME Fixed on AMD Ryzen

As expected, AMD fixed the problem with VME that affected Ryzen processors. The fix is shipped in the form of a microcode patch as part of AGESA 1.0.0.6, currently being rolled out by OEMs as part of a BIOS update. … Continue reading

Posted in AMD, Bugs | 17 Comments

Rich Heimlich’s Patch Set Overview

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

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 | 42 Comments

How Many Gravis UltraSounds?

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 | 49 Comments

VME Broken on AMD Ryzen

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 | 35 Comments

SGDT/SIDT Fiction and Reality

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 | 37 Comments