Author Archives: Michal Necasek

EISA Specification 3.1

Posted on June 9, 2021 by Michal Necasek

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

Posted on June 5, 2021 by Michal Necasek

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

Whence IDENTIFY DRIVE?

Posted on June 4, 2021 by Michal Necasek

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

OS/2 1.2 EE DAP

Posted on June 2, 2021 by Michal Necasek

That same shoebox I mentioned the other day also contained three plain cardboard 3.5″ floppy boxes with a set of disks that look like this: Once again, despite the plain-looking labels, these are mass-duplicated floppies, which is handy because Kryoflux … Continue reading →

Posted in Archiving, IBM, Kryoflux, OS/2, PC history | 2 Comments

Like New

Posted on May 31, 2021 by Michal Necasek

About twenty years ago, I bought a used IBM Model M keyboard with a PS/2 connector. I believe it cost me around $5-$10 plus shipping at the time. A good investment, given that this sort of keyboard is probably worth … Continue reading →

Posted in IBM, Keyboard, PC hardware | 5 Comments

Archival Puzzles

Posted on May 28, 2021 by Michal Necasek

Every now and then I attack the large amount of floppy disks in my basement and run a bunch of them through Kryoflux. This time it was a shoebox full of OS/2 related floppies. Among them was a very incomplete … Continue reading →

Posted in Archiving, IBM, Kryoflux, OS/2, Pre-release | 30 Comments

DOS SMB Client Performance

Posted on May 20, 2021 by Michal Necasek

Recently I had the need to use several different DOS VMs that all used a SMB network client. Although I did not use networking heavily, I noticed that there are massive differences in performance between the VMs. Copying a circa … Continue reading →

Posted in DOS, IBM, Microsoft, Networking | 15 Comments

It Was a Problem Back in the Day

Posted on May 19, 2021 by Michal Necasek

Several years ago, I found out the hard way that old versions of DOS have trouble with hard disks with more than 17 sectors per track. To recap, DOS versions older than 3.3 may hang when booting from a hard … Continue reading →

Posted in Bugs, DOS, ESDI, Storage | 26 Comments

Installing IBM OS/2 1.0 in a VirtualBox VM

Posted on April 30, 2021 by Michal Necasek

Some time ago I wrote that IBM OS/2 1.0 and 1.1 cannot be installed in a VM due to the way it switches between real and protected mode. At the time I did not realize that there was another obstacle, … Continue reading →

Posted in OS/2, VirtualBox, Virtualization | 18 Comments

Nobody Expects…

Posted on April 14, 2021 by Michal Necasek

…the Spanish Inquisition! Well, that too, but also nobody expects that a bland, run-of-the mill Novell NE2000 NDIS driver would crash/hang just because it runs on 486 or later CPUs. I wanted to try the “basic” DOS redirector shipped with … Continue reading →

Posted in 486, Bugs, Intel, Microsoft | 7 Comments