Twenty-five years ago, on March 31st, 1992, IBM released OS/2 2.0, the first mass-market 32-bit PC operating system. The road to OS/2 2.0 was quite long and winding, and the OS was a proud member of the vaporware club (just like, say, Windows NT or Windows 95).
Talk of 32-bit OS/2 goes almost as far back as OS/2 itself. In 1987, Gordon Letwin wrote about OS/2-386 in Inside OS/2 and it is clear that future 32-bit extension was a consideration when OS/2 1.0 was on the drawing board. And we now know that in late 1986, Microsoft already started experimenting with using the 80386’s V86 mode to run Virtual DOS Machines (VDMs) on top of OS/2.
Microsoft launched actual development of OS/2 2.0 probably in 1988, the same year development of NT OS/2 (later known as Windows NT) started. The goal was to provide a PC operating system which is upwardly compatible with OS/2 1.x, supports native 32-bit applications, and supports VDMs; the latter was especially important in light of the fact that compatibility with existing DOS applications was a weak point of OS/2 1.x.
The entire history of OS/2 2.0 development is one of missed deadlines and broken promises. In July 1988, OS/2 2.0 was supposed to be released in early 1989. In February 1989, an OS/2 2.0 SDK was supposed to be released by the end of the year and the finished product in 1990.
Microsoft did ship the OS/2 2.0 SDK by the end of 1989—just. On the last business day of 1989, the $2,600 MS OS/2 2.0 SDK became available.
There is no known surviving copy of a MS OS/2 2.0 SDK. The only known fragment is the development tool set (C compiler, assembler, OS/2 headers and libraries, electronic documentation) from Summer 1990:
The disks aren’t even original—they are copies, made back in 1990 at a certain U.S. Airline which signed up for the SDK program. The disks were donated to the OS/2 Museum about 15 years ago and since then, only parts of the MS OS/2 2.0 SDK printed documentation have been sighted, nothing else.
In the second half of 1990, things fell apart. The tensions between Microsoft and IBM became unsustainable, especially after the runaway success of Microsoft’s Windows 3.0. Irreconcilable differences were followed by a divorce, and the companies parted ways. On September 19, 1990, IBM announced that it is taking over OS/2 development, including OS/2 2.0.
By January 1991, IBM was promising OS/2 2.0 release in March 1992, with free upgrades for purchasers of IBM’s OS/2 1.3. IBM decided that that deadline was going to stick, come hell or high water. And it did.
Not surprisingly, IBM’s OS/2 2.0 was a bit of a rush job. Up to 1990, IBM was concentrating on the development of OS/2 1.3, with Microsoft working on OS/2 2.0. When Microsoft quit, it took IBM many months to get up to speed with OS/2 2.0 development.
IBM also had a serious problem in that with Microsoft gone, a 32-bit C compiler (cl386) was also gone. IBM Toronto rapidly put together a 32-bit compiler for OS/2 2.0, released in 1992 as CSet/2 1.0. IBM also aggressively courted third-party compiler vendors and announced agreements to support OS/2 with Borland (May 16, 1991) and Watcom (August 7, 1991).
The most controversial and most heralded feature of IBM’s OS/2 2.0 was the Workplace Shell (WPS), a modern object-oriented user interface. The WPS was not present in MS OS/2 2.0 SDK and not even the early IBM pre-releases of OS/2 2.0 (e.g. Level 6.149 from July 1991); those used the same simplistic shell as OS/2 1.3.
The WPS was very nifty and impressive, but it was also not entirely stable (especially the use of INI files was error prone) and it consumed a fair amount of memory. That didn’t help when memory was already expensive and OS/2 2.0 required 4 MB to run at all, and 6-8 MB to run acceptably well. In hindsight, jamming WPS into OS/2 2.0 (rather than some later, more stable release) seems like an unhappy decision.
The following is a timeline of OS/2 2.0 betas, whatever they were called at the time—SDK, pre-release, Early Experience Program, and more. No complete official information exists but enough can be pieced together from contemporary press reports and newsgroup discussions. The dates may be inaccurate and where known, refer to the label printed on the disks. Users typically received the disks with a slight delay.
- 6.43, 12/89, first MS OS/2 SDK
- 6.78, 7/90
- IBM took over OS/2 development in 9/90
- 6.123, 2/91, last MS OS/2 SDK, also shipped by IBM
- 6.149, 7/91, first IBM OS/2 2.0
- 6.167 (Comdex preview), 10/91, included WPS
- 6.177 aka 2.0 LA (Limited Availability), 12/91
- 6.304, 02/92
- 6.307 aka 2.0 GA, 3/92, final OS/2 2.0
The information is primarily based on contemporary newsgroup and press reports, there is no official information. Based on the surviving reports, it is unlikely that another OS/2 2.0 pre-release would have existed.
A big OS/2 2.0 push started at Fall Comdex 1991. For that occasion, IBM put together OS/2 2.0 build level 6.167, also known as Comdex beta. OS/2 2.0 6.167 was reasonably close to the finished product. It sported the Workplace Shell, fully supported VDMs, full-screen Win-OS/2 sessions, and came with Boot Manager.
OS/2 2.0 6.167 was shipped in a cardboard box with a modicum of printed documentation. It was clearly a pre-release product but not just a hastily produced beta with labels from a dot matrix printer.
OS/2 2.0 6.167 was a good preview of the final (GA, or General Availability) release. It included all major OS/2 2.0 functionality with the exception of seamless Win-OS/2. The boot-up screen did not look quite like OS/2 2.0 GA:
There was a nice-looking graphical installer, a clear improvement over OS/2 1.x:
The installed product looked a lot like the finished product, with the familiar WorkPlace Shell:
One clear visual difference was the program/folder icon on the left of the title bar, removed in the final version.
Full-screen Win-OS/2 was in place, of course supporting Windows 3.0—Windows 3.1 was released shortly after OS/2 2.0.
All in all, in October 1991 OS/2 2.0 was still five months away, but its shape could be very clearly seen.
But Wait, There’s More
OS/2 2.0 6.167 of course wasn’t the only pre-release of OS/2 2.0 (see timeline above). Some other disks survived as well. For example build 6.304 from February 1992, just before the final release:
Or the older and somewhat mysterious build 6.605:
Why mysterious? Because the 6.605 “level” does not fit into the sequence at all (the final OS/2 2.0 GA was 6.307). Also because the disks are labeled 7/91 but the files on the disks are dated September 1991. It appears that 6.605 was a minor update to 6.149 but the out-of-sequence numbering is not understood.
At any rate, the 6.605 and the newer 6.304 disks sets in OS/2 Museum’s possession are both incomplete, and incomplete enough that even a most basic installation can’t be put together.
However… not long before this article was published, hopefully complete disk sets (at least the base OS) of build 6.605 as well as 6.177 from the end of 1991 turned up. As of this writing, they are still in transit. Watch this space.