Category Archives: OS/2

IBM OS/2 1.0 in a VM

Posted on March 21, 2014 by Michal Necasek

As previously mentioned, IBM’s OS/2 1.0 and 1.1 is extra unfriendly to modern hypervisors. To recap, there is a curious difference between IBM’s and Microsoft’s kernels in OS/2 1.0/1.1 with regard to mode switching. For reasons that aren’t very clear, … Continue reading →

Posted in IBM, Microsoft, OS/2, VirtualBox, Virtualization | 36 Comments

Fantasy History at Ars Technica

Posted on November 26, 2013 by Michal Necasek

Ars Technica today published an article titled “Half an operating system: The triumph and tragedy of OS/2“. Although very interesting, unfortunately the article to a significant extent engages in what can best be called fantasy history, which causes the text … Continue reading →

Posted in IBM, Microsoft, OS/2 | 51 Comments

LOADALL Strikes Again

Posted on October 18, 2013 by Michal Necasek

A minor mystery recently popped up while running IBM’s OS/2 1.1 (1988), the first OS/2 version with the Presentation Manager GUI. While Microsoft’s and IBM’s releases of OS/2 were fully compatible from application perspective, there were differences in the drivers … Continue reading →

Posted in IBM, Intel, Microsoft, OS/2, x86 | 11 Comments

Taking Screenshots of OS/2 on ThinkPad 850

Posted on October 3, 2013 by Michal Necasek

An article about OS/2 on a PowerPC-based ThinkPad 850 needed a few screenshots for illustration. Once an OS is installed and running a GUI, it’s typically possible to run a screen grab utility and capture screenshots digitally. But that’s not an … Continue reading →

Posted in OS/2, PowerPC | 4 Comments

OS/2 on ThinkPad 850

Posted on September 27, 2013 by Michal Necasek

The ThinkPad 850 was no ordinary ThinkPad. It was IBM’s high-end portable multimedia workstation, built around a 100MHz PowerPC 603e processor, with a list price of $12,399 (February 1996). The ThinkPad 850 was originally slated (see IBM announcement letter 195-176) to … Continue reading →

Posted in IBM, OS/2, PowerPC | 18 Comments

Why Won’t IBM’s MSPS201.SYS Load?

Posted on August 23, 2013 by Michal Necasek

Recently a minor mystery resurfaced. When IBM’s OS/2 1.2 SE is installed on any “normal” system (either physical or virtual) and the PS/2 mouse driver is installed (the typical choice), the mouse won’t work: The MSPS201.SYS driver is intended for … Continue reading →

Posted in IBM, OS/2 | 7 Comments

Detecting an Empty Drive… Or Not

Posted on August 3, 2013 by Michal Necasek

Detecting an empty drive with a NEC uPD765A or compatible FDC is theoretically easy using the ‘drive ready’ signal. In practice, the drive ready mechanism is completely unusable on IBM PCs and compatibles due to the way the FDC is … Continue reading →

Posted in OS/2, PC hardware | 16 Comments

OS/2 2.0 LA and “Large” IDE Disks

Posted on July 26, 2013 by Michal Necasek

Attempting to boot OS/2 2.0 LA (Limited Availability) on many systems built in the last 20 years often results in the following crash: The trap screen claims there was an exception (Trap 0 or division overflow) in device driver A:, … Continue reading →

Posted in IDE, OS/2 | 4 Comments

The Oldest OS/2 Executable In the Wild

Posted on March 22, 2013 by Michal Necasek

While researching the history of Microsoft’s segmented-executable linker originally called LINK4.EXE, I came across an OS/2 executable that was publicly released almost a year before the first OS/2 SDK was shipped, and many months before OS/2 was even announced. In … Continue reading →

Posted in DOS, Microsoft, OS/2 | 16 Comments

OS/2 2.1 National Language Versions

Posted on March 1, 2013 by Michal Necasek

IBM’s OS/2 2.1 (1993) was shipped in a number of national language versions (NLVs). At the time, the US version of OS/2 was the “master copy” and all NLVs were derived from it.  There were two major classes of NLVs: … Continue reading →

Posted in IBM, OS/2 | 7 Comments