Author Archives: Michal Necasek

OS/2 Kernel Debugger and MVDM Interrupts

Posted on August 29, 2014 by Michal Necasek

While working on an unrelated problem, I noticed a strange behavior of one of my OS/2 VMs running OS/2 Warp 4.52. To cut a long story short, if an unhandled floating-point exception occurred in a DOS window (VDM, or Virtual … Continue reading →

Posted in Bugs, Debugging, OS/2 | 12 Comments

IBM Blue Lightning: World’s Fastest 386?

Posted on August 22, 2014 by Michal Necasek

One of the OS/2 Museum’s vintage boards is a genuine Made in U.S.A. Alaris Cougar. These boards were produced by IBM for Alaris and are a bit unusual: There’s a small IBM DLC3 processor in plastic package soldered on board, … Continue reading →

Posted in 386, IBM, Intel, PC hardware, PC history | 62 Comments

Semantic Differences, Microsoft v. Microsoft

Posted on August 8, 2014 by Michal Necasek

While comparing the behavior of various versions of old Microsoft C compilers, I tried building a trivial hello-world type program with CL.EXE from Microsoft C/C++ 7.0 (March 1992) running on top of a 32-bit Windows Server 2003. This seemingly trivial … Continue reading →

Posted in DOS, Microsoft, Virtualization | 14 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 | 50 Comments

Windows Presentation Manager Documentation

Posted on July 20, 2014 by Michal Necasek

The OS/2 Museum just posted a three-volume set of draft Windows Presentation Manager reference documentation. This refers to the OS/2 Presentation Manager GUI but highlights the story Microsoft pushed in 1987: Windows and OS/2 both used the same graphical user … Continue reading →

Posted in Documentation, Microsoft, OS/2 | 5 Comments

OS/2 Programmer’s Toolkit

Posted on July 11, 2014 by Michal Necasek

For those wishing to write OS/2 1.x programs, the complete Microsoft OS/2 Programmer’s Toolkit documentation is now online. This is Microsoft’s programming documentation for OS/2 1.0 programming. It is worth noting that IBM’s programming documentation was different; worse yet, IBM’s … Continue reading →

Posted in Development, Documentation, Microsoft, OS/2 | 2 Comments

Weekend Reading, OS/2 and Windows

Posted on July 4, 2014 by Michal Necasek

In a recent post I mentioned that the OS/2 Museum’s stack of PC Tech Journal issues ironically does not include the first PCTJ issue devoted to OS/2. Thanks to pcjs.org, the October 1987 issue of PCTJ can now be read … Continue reading →

Posted in Documentation, Microsoft, OS/2, Windows | 3 Comments

Careful with that Buffer…

Posted on June 29, 2014 by Michal Necasek

Last week I was sorting through several sets of Microsoft C 5.1 disks from 1988  (more about that later). While I was comparing the disk images to see whether the disks were the same or not, despite different labels and part … Continue reading →

Posted in Microsoft, Security | 13 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 | 7 Comments

Intel 287XL… From 1986? Or 1996?

Posted on June 14, 2014 by Michal Necasek

Many or most readers of this site probably know that most chips (and PCBs) have the date of manufacture stamped on them, almost always indicating the year and week (usually not the actual date) they were made. Especially with PCBs, … Continue reading →

Posted in Intel, PC history | 12 Comments