Category Archives: Documentation

Frequently Given Misleading Answers

Posted on February 21, 2018 by Michal Necasek

The other day I came across this FGA item describing how to detect virtualized environments. It includes interesting comments which make Microsoft, Intel, and AMD sound stupid, but perhaps only reflect on the author being either deliberately misleading, or trying … Continue reading →

Posted in Corrections, Documentation, Virtualization | 9 Comments

AMD64 APM Archive Online

Posted on December 29, 2017 by Michal Necasek

Thanks to Konstantin Belousov, the OS/2 Museum AMD64 APM (Architecture Programmer’s Manual) is now available online. Big thanks to blog readers who recently supplied several missing revisions of the documents. This is a nearly complete archive of all published AMD64 … Continue reading →

Posted in AMD, AMD64, Documentation | 2 Comments

How Fast Again?

Posted on December 27, 2017 by Michal Necasek

Or, Yet Another Wikipedia Mystery Looking for something on the Wikipedia USB page, a detail caught my eye. In the version history section, both the table and the text claim that the original 1996 USB 1.0 specification defined 1.5 Mbps … Continue reading →

Posted in Documentation, USB | 36 Comments

AMD64 Manual Vol. 3 Rev. 3.24 Anyone?

Posted on December 24, 2017 by Michal Necasek

AMD tricked me. After not updating anything for months, they updated the AMD64 documentation and not only that, they updated Volume 3 (instruction reference) twice within a few weeks. First to revision 3.24 in November, then 3.25 in December. I … Continue reading →

Posted in AMD, Documentation | 3 Comments

HTT Means Hyper-Threading, Right?

Posted on December 11, 2017 by Michal Necasek

In a logical, ordered world, the HTT bit in CPUID would indicate a processor with Hyper-Threading Technology enabled. But of course the world with Intel inside is anything but logical. The actual meaning of the HTT bit changed several times … Continue reading →

Posted in Documentation, Intel, Pentium 4 | 13 Comments

MS KB Articles

Posted on October 17, 2017 by Michal Necasek

A recent blog post over at pcjs.org explores some of the mysteries surrounding information that at one point or another was published as a Microsoft KnowledgeBase article (or a KB article for short). It’s not entirely clear where the KB … Continue reading →

Posted in Documentation, Microsoft, PC history | 17 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

Finally Free

Posted on January 4, 2017 by Michal Necasek

For a while I’ve been toying with the idea of buying the full official MIDI specification, but never went through with it. Not so much because of the cost ($100 for the core spec) but because of the hassle. Only … Continue reading →

Posted in Documentation, MIDI | 6 Comments

IBM OS/2 1.x Programming Documentation Added

Posted on April 15, 2016 by Michal Necasek

IBM’s programming documentation (Programming Tools and Information, aka PTI) for OS/2 versions 1.2 and 1.3 has been added. Big thanks to Bob Eager who scanned the originals and converted them to PDF. The documents have been added to the OS/2 … Continue reading →

Posted in Development, Documentation, IBM, OS/2 | 2 Comments

Periscope Manuals

Posted on March 1, 2016 by Michal Necasek

Some time ago I recovered a latter-day Periscope manual from storage. Since some readers might find it useful, I decided to scan the manual and convert it to PDF. It covers the basic Periscope debugger, variants and add-ons (remote Periscope, … Continue reading →

Posted in Debugging, Documentation | 7 Comments