Category Archives: Documentation

EISA Specification 3.1

While researching the Compaq Intelligent Drive Array (IDA), a circa 1990 EISA-based IDE RAID controller, I quickly established that there’s very little surviving information about it, and most of what there is can be found in two or three patents … Continue reading

Posted in Documentation, EISA | 19 Comments

WD1007V Commands

While researching material for a previous article, I wanted to examine the only AT-compatible ESDI controller I have, a Western Digital WD1007V-SE2. My board was made in 1990, the firmware is from 1989, and the controller was likely introduced in … Continue reading

Posted in Debugging, Documentation, ESDI, Western Digital | 3 Comments


As most everyone knows, the AT Attachment standard (informally known as IDE) started by literally bolting the previously standalone AT disk controller onto a MFM drive with a ST506 interface and connecting the assembly to the host system with a … Continue reading

Posted in Compaq, Documentation, IDE, PC hardware, PC history, Storage | 36 Comments

MS OS/2 SDK Document Dump

The Microsoft OS/2 1.0 SDK library section got a big fat update. Over the holidays I managed to finalize and upload about 25 PDFs, some of which have been lying on my NAS in 98% completed state for almost 10 … Continue reading

Posted in Documentation, Microsoft, OS/2 | Leave a comment

LAN Manager Product Specification, 1987

Now available is the preliminary yet fairly complete product specification for the LAN Manager server and workstation from October 14, 1987. This document was available to developers months before any pre-release LAN manager code, and about a year before any … Continue reading

Posted in Archiving, Documentation, LAN Manager, Microsoft, OS/2, PC history | 1 Comment

Microsoft OS/2 Programmer’s Guide

For once, the OS/2 Museum lives up to its name… After a long pause, a new document from the MS OS/2 SDK has been uploaded. It’s the pre-release Microsoft Operating System/2 Programmer’s Guide from April 1987. This document was part … Continue reading

Posted in Documentation, Microsoft, OS/2 | Leave a comment

The History of a Security Hole

Warning: If you do not care for the finer points of x86 architecture, please stop reading right now—in the interest of your own sanity. A while ago I was made aware of a strange problem causing a normal user process … Continue reading

Posted in 386, BSD, Bugs, Documentation, PC history | 44 Comments

USB 0.9

A couple of months ago I lamented the fact that historic USB documentation appears to have vanished from the face of the Earth. Today I finally found one such document, the USB 0.9 specification from April 13, 1995, published almost … Continue reading

Posted in Documentation, PC history, USB | 30 Comments

ICEBP Finally Documented

After more than 30 years, Intel finally documented the INT1 instruction, also known as ICEBP (opcode F1h), in the latest (May 2018, -067) edition of the SDM. This was probably forced by security concerns, because from a security standpoint, having … Continue reading

Posted in 386, Documentation, Intel, Undocumented | 14 Comments

Undocumented RDTSC

The other day I wrote a simple DOS program which used the RDTSC instruction in order to obtain precise time measurements (of how long it takes a PS/2 keyboard to send data; more about that some other time). The 16-bit … Continue reading

Posted in Documentation, Intel, Pentium | 15 Comments