Category Archives: Graphics

Windows 3.x VDDVGA

Posted on January 23, 2023 by Michal Necasek

While working on my Windows 3.x display driver, I ran into a vexing problem. In Windows 3.1 running in Enhanced 386 mode, I could start a DOS session and switch it to a window. But an attempt to set a … Continue reading →

Posted in 386, Development, Documentation, Graphics, PC history, Windows | 59 Comments

Reconstructing the EGA BIOS

Posted on March 19, 2022 by Michal Necasek

A few weeks ago I had a sudden need to understand certain finer points of the operation of EGA/VGA BIOS. I found common reference materials to be inadequate—they tend to do a good job of documenting the data structures the … Continue reading →

Posted in BIOS, Development, Documentation, Graphics, IBM, PC history | 32 Comments

Broken Spigot

Posted on June 18, 2015 by Michal Necasek

While searching for an unrelated piece of hardware, I came across an old video capture board. Alarm bells started going off when I heard something rattling in the anti-static wrap. Sure enough, one of the large capacitors fell off… because … Continue reading →

Posted in Graphics, PC hardware, PC history | 3 Comments

sips To the Rescue

Posted on April 17, 2015 by Michal Necasek

A few days ago I scanned a document and unwisely used MS Paint on Windows 7 to touch up a small selection of the scanned pages. Once the dozen or so files were re-touched, I combined them into a PDF … Continue reading →

Posted in Graphics, OS X | Leave a comment

A Tale of Two Displays

Posted on November 8, 2014 by Michal Necasek

By sheer coincidence, two new computers arrived in my family at almost the same time, and they couldn’t be more different. At first sight, the most striking difference is the quality of their displays, and it says a lot about … Continue reading →

Posted in Apple, Graphics, PC hardware | 10 Comments

NT Video Miniport for VirtualBox, With Source Code

Posted on August 1, 2014 by Michal Necasek

Note: See also an updated version. Upon reader request, the OS/2 Museum is publishing the source code to the NT video miniport driver for VirtualBox. To recap, this is a NT video miniport which allows 32-bit NT versions to use high-resolution graphics … Continue reading →

Posted in Graphics, NT, Source code, VirtualBox | 48 Comments

S3 Fraternal Twins

Posted on June 20, 2014 by Michal Necasek

Sometimes identifying old hardware is a bit tricky. Consider these two graphics cards: The PCB is the same, the BIOS chips look the same, the DAC is slightly different but an 80 MHz part in both cases, memory is the … Continue reading →

Posted in Graphics, PC hardware, S3 | 5 Comments

The ISA OSC Mystery

Posted on April 3, 2014 by Michal Necasek

About twenty years ago I ended up with a spare ISA graphics card from an upgraded computer. It was a SVGA card based on the Cirrus Logic CL-GD5422 chip, equipped with 1 MB video memory. This was a very cheap … Continue reading →

Posted in Cirrus Logic, Graphics, PC hardware | 15 Comments

Early PCI Board

Posted on January 28, 2014 by Michal Necasek

Since some of this blog’s readers are very good at recognizing obscure hardware, I thought I’d post photos of one more somewhat exotic graphics card: This board was one of the early PCI graphics adapters. It’s old enough that it … Continue reading →

Posted in Graphics, PC hardware | 27 Comments

Two More TIGAs

Posted on January 24, 2014 by Michal Necasek

Since some readers appear to enjoy identifying prehistoric graphics cards, I thought I’d post photos of two more TIGA boards from my junk pile. I know what these are, but do you? One of them ought to be fairly easy … Continue reading →

Posted in Graphics, PC hardware | 14 Comments