Category Archives: VGA

Learn Something Old Every Day, Part X: The VGA Attribute Controller Is Weird

Posted on May 3, 2024 by Michal Necasek

A few days ago I finally swatted a VGA emulation bug that I had known about for several years, but couldn’t identify until recently. The problem affected only Windows 3.1 running in Standard mode. It did not occur in Windows … Continue reading →

Posted in Bugs, PC hardware, VGA | 9 Comments

Xenix 2.2 vs. VGA

Posted on April 15, 2022 by Michal Necasek

The other day I started wondering why certain old versions of 286 and 386 XENIX look a bit weird in emulation: The characters are cut off, because XENIX sets up an EGA text mode with 8×14 character matrix but uses … Continue reading →

Posted in 286, 386, PC architecture, PC history, VGA, Xenix | 14 Comments

FantasyLand on VGA

Posted on April 3, 2022 by Michal Necasek

In 1984, Joel Gould of IBM Cambridge (that is Cambridge, Massachusetts rather than Cambridge, UK) Scientific Center wrote a demo program named FantasyLand. This demo was meant to show off the capabilities of IBM’s brand new Enhanced Graphics Adapter, or … Continue reading →

Posted in IBM, PC hardware, PC history, VGA | 16 Comments

More ISA VGA Benchmarks

Posted on November 6, 2015 by Michal Necasek

After establishing that Trident VGA cards are indeed very slow, the natural follow-up question is: Are there cards even slower than that? But not some 8-bit VGA card from the 1980s (or a Realtek from the 1990s), and not some … Continue reading →

Posted in Cirrus Logic, IBM, S3, VGA | 9 Comments

About Those Trident VGAs…

Posted on October 30, 2015 by Michal Necasek

An earlier post mentioned that the performance of Trident-based ISA VGA cards leaves much to be desired. A reader pointed out that such cards tend to have switchable 8-bit/16-bit bus width and performance might suffer if the card is incorrectly jumpered. … Continue reading →

Posted in Trident, VGA | 17 Comments

Fast Unaccelerated VGA?

Posted on October 26, 2015 by Michal Necasek

For the purpose of comparing the relative real-world performance of various processors, it’s useful to run CPU and graphics-intensive benchmarks such as 3DBench or DOOM. To avoid benchmarking the graphics card instead, the VGA has to have enough headroom so … Continue reading →

Posted in 386, ATi, S3, VGA | 27 Comments

Windows NT BSOD Aclock Port

Posted on November 7, 2012 by tenox

Do you remember the famous Windows NT Blue Screen Of Death? For years it was a source of jokes and bad reputation of Windows reliability. There even was a Blue Screen Saver! Today we fortunately see much less of it, but it … Continue reading →

Posted in 386, Development, NT, VGA, Windows, x86 | 10 Comments

Undocumented VflatD

Posted on February 23, 2012 by Michal Necasek

The virtual flat framebuffer driver, or VflatD, was introduced in Windows 95 in order to ease development of display drivers. It was surprisingly poorly documented and the sample drivers did not illustrate its use very well. A short backgrounder may … Continue reading →

Posted in Documentation, VGA, Windows | 2 Comments

DOS/V graphics text modes and scrolling

Posted on January 22, 2012 by Michal Necasek

I recently ran into an interesting difference in the way various DOS/V versions manage VGA memory. DOS/V of course refers to the Japanese versions of DOS which are capable of running on standard “Western” hardware. Microsoft has a very long … Continue reading →

Posted in DOS, VGA | Leave a comment