Category Archives: OS/2

OS/2 Kernel Debugger and MVDM Interrupts

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 | 11 Comments

Windows Presentation Manager Documentation

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

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

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, the October 1987 issue of PCTJ can now be read … Continue reading

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

Microsoft OS/2 1.3… But Which One?

A recent inventory at the OS/2 Museum revealed that two seemingly identical sets of Microsoft OS/2 1.30.1 disk images were in fact not identical at all. Probably thanks to the twilight status of OS/2 at Microsoft in the days of OS/2 1.3, Microsoft … Continue reading

Posted in Microsoft, OS/2 | 21 Comments

OEM MS OS/2: 1987-1990

When Microsoft started offering OS/2, the arrangement was roughly similar to how DOS 3.3 had been handled: Microsoft and IBM jointly developed the code, IBM maintained its own version, and Microsoft licensed an “adaptation kit” to OEMs. While the IBM … Continue reading

Posted in Microsoft, OS/2 | 17 Comments

Multitasking MS-DOS 4.0, Goupil OEM

The recently unearthed copy of the near-mythical Multitasking (aka European) MS-DOS 4.0 clearly did not want to be alone. James Lariviere, a kind reader of this blog, provided a disk image of multitasking DOS 4 which was released in 1986 … Continue reading

Posted in DOS, Microsoft, OS/2 | 29 Comments

IBM OS/2 1.0 in a VM

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 | 35 Comments

Fantasy History at Ars Technica

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 | 50 Comments

LOADALL Strikes Again

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 | 9 Comments