Author Archives: Michal Necasek

Antique Display Driving

Posted on July 29, 2022 by Michal Necasek

Here’s a preview of something I’ve been slowly working on, bit by bit: That screenshot surely looks a little funny. That’s because it is Windows 1.04 running with a heavily modified 256-color Windows 3.x display driver, using resources from a … Continue reading →

Posted in Development, Microsoft, Windows | 35 Comments

Learn Something Old Every Day, Part VI: Backward Buffer Overwrite

Posted on July 13, 2022 by Michal Necasek

A few days ago I spent far too much time debugging a largish piece of 16-bit Windows code written in assembler. I found a scenario where (fortunately fairly reproducibly) Windows crashed because the internal state of a DLL got corrupted. … Continue reading →

Posted in Bugs, Development, Windows | 24 Comments

Windows 9x Video Minidriver Source Code

Posted on June 24, 2022 by Michal Necasek

As promised, here is the source code for the Windows 9x VirtualBox display minidriver. For discussion of the source code, see the included readdev.txt file. The code was developed on a Windows 10 host system. For extra credit, I attempted … Continue reading →

Posted in Development, Source code, VirtualBox, Watcom, Windows 95 | 16 Comments

WordSet: Stolen Without Compensation

Posted on June 21, 2022 by Michal Necasek

A kind reader from a land formerly beyond the Iron Curtain recently supplied the OS/2 Museum with a curious word processor that calls itself WordSet. The files unfortunately lost their original timestamps quite some time ago, but it is apparent … Continue reading →

Posted in Editors, I18N, PC history, WordStar | 29 Comments

Windows 9x Video Minidriver HD+

Posted on June 6, 2022 by Michal Necasek

The OS/2 Museum has made available the first version of a display driver disk for Windows 9x running on VirtualBox. The driver uses a linear framebuffer and supports 8/16/24/32bpp modes with resolutions up to 1920×1200 pixels (see more below). The … Continue reading →

Posted in Development, VirtualBox, Watcom, Windows 95 | 52 Comments

Compaq EGA Technical Reference Guide

Posted on June 1, 2022 by Michal Necasek

A rater nice Compaq EGA Tech Ref recently turned up on archive.org, under the title COMPAQ Enhanced Color Graphics Board Technical Reference Guide. It’s from December 1986, relatively late in EGA’s life (given that it was about to be obsoleted … Continue reading →

Posted in Compaq, Documentation, PC history | Leave a comment

NT video miniport UHD

Posted on May 27, 2022 by Michal Necasek

I’ve finally managed to update the previously released NT video miniport. The reason for the update was indirect, hacking up the video “hardware” access code to support other environments. That led me to separate the generic mode set code from … Continue reading →

Posted in NT, VirtualBox | 1 Comment

IDENTIFY ESDI DRIVE

Posted on May 25, 2022 by Michal Necasek

As previously mentioned on this site, the IDENTIFY DRIVE command in the ATA specification almost certainly first appeared in ESDI controllers supplied to Compaq by Western Digital. Since I have now finally secured a working ESDI hard disk, I could … Continue reading →

Posted in ESDI, IDE, PC hardware, PC history, Western Digital | 19 Comments

The Strange Case of GetEnvironmentStringsA

Posted on May 22, 2022 by Michal Necasek

It was recently pointed out to me that a simple “hello world” style application built with Open Watcom C/C++ 1.9 does not run on Win32s version 1.30, even though the same executable runs just fine on Windows NT 3.51, Windows … Continue reading →

Posted in Development, NT, Watcom | 17 Comments

1989 Networking: OS/2 NetWare Requester 1.1

Posted on May 7, 2022 by Michal Necasek

When I wrote about the pre-release NetWare Requester for OS/2, the oldest archived officially released NetWare OS/2 Requester was version 1.2 from 1990. In the meantime, version 1.1 of the requester showed up, although I only became aware of that … Continue reading →

Posted in NetWare, Networking, OS/2, PC history, Virtualization | 9 Comments