Author Archives: Michal Necasek

The Secret History of ATAPI

Posted on November 24, 2021 by Michal Necasek

The other day I asked myself a seemingly trivial question: What was the first ATAPI CD-ROM drive and when was it available? Given that ATAPI was a major technology which instantly obsoleted all proprietary CD-ROM interfaces and made SCSI much … Continue reading →

Posted in CD-ROM, PC history, Standards, Undocumented | 60 Comments

Looking for High Sierra

Posted on October 29, 2021 by Michal Necasek

Some time ago, I thought it would be useful to understand exactly what is the difference between CD-ROMs recorded in the old High Sierra format versus the ISO 9660 standard. This was in part spurred by the fact that I … Continue reading →

Posted in CD-ROM, Documentation, PC history | 23 Comments

Deeper Into ATA History

Posted on October 14, 2021 by Michal Necasek

While looking for something completely unrelated (namely the Rock Ridge extensions to ISO 9660), I came across a cache of old X3T9 committee documents from 1990. In retrospect I’m a little surprised that I hadn’t found these earlier, since the … Continue reading →

Posted in IDE, PC history, Standards | 17 Comments

Weird Tales

Posted on October 1, 2021 by Michal Necasek

While researching various aspects of the history of computing, sometimes I come across what can best be described as “weird tales” — unsourced claims that sound interesting but are either provably wrong or there’s no evidence to support them. In … Continue reading →

Posted in IBM, Microsoft, PC history, PC press | 22 Comments

DOS 2.11 From Scratch

Posted on September 21, 2021 by Michal Necasek

Warning: Long post! After having good luck with rebuilding core PC DOS 1.1 from source code, I thought I’d do the same with the DOS 2.11 source code released by the CHM. What follows is largely a collection of notes … Continue reading →

Posted in Development, DOS, Microsoft, PC history | 42 Comments

PC DOS 1.1 From Scratch

Posted on September 10, 2021 by Michal Necasek

A number of years ago, the Computer History Museum together with Microsoft released the source code for MS-DOS 1.25 (very close to PC DOS 1.1) and MS-DOS 2.11. I never did anything with it beyond glancing at the code, in … Continue reading →

Posted in Development, DOS, Microsoft, PC history | 24 Comments

Learn Something Old Every Day, Part III

Posted on September 8, 2021 by Michal Necasek

As part of a hobby project, I set out to reconstruct assembly source code that should be built with an old version of MASM and exactly match an existing old binary. In the process I learned how old MASM versions … Continue reading →

Posted in Assembler, Development, Microsoft, PC history | 11 Comments

PC-86-DOS

Posted on September 3, 2021 by Michal Necasek

A number of years ago, an 8″ disk containing Seattle Computer Products (SCP) 86-DOS 1.0 was successfully imaged. The newest files on the disk are dated April 30, 1981, making the disk the oldest complete release of what was soon … Continue reading →

Posted in Development, DOS, IBM, PC history | 18 Comments

The Dual-Drive IDE Hell

Posted on August 25, 2021 by Michal Necasek

I have perhaps inaccurate but very strong memories from my PC-building days (in the early to mid-1990s) that one of the most failure-prone and frustrating endeavors was trying to get two IDE drives working together on a single cable as … Continue reading →

Posted in IDE, PC hardware, PC history | 20 Comments

Drive Price Mystery

Posted on August 17, 2021 by Michal Necasek

While digging into the history of DoubleSpace and DriveSpace, I came across a handy article about the rocky relationship between Stac Electronics and Microsoft. Only I was distracted by the bold claim (certainly claimed in very bold letters) that a … Continue reading →

Posted in PC history, Storage | 16 Comments