Someone just bought a version of OS/2 2.0 from Microsoft, not IBM, on eBay...
Looking at the eBay photos, the whole thing is 26 floppies.
However, MS and IBM were already getting "divorced", and this may have been a token part of the settlement. A year later, MS shipped Windows NT.
The OS/2 interregnum was quite long. All those years Microsoft was still selling their 16-bit OS/2 1.3 because their server software (including SQL Server) ran on that platform.
Microsoft and IBM had a joint development agreement for many years. When they "divorced" in 1992, they both retained rights to DOS 5, Windows 3.0, and OS/2 2.0.
Microsoft had NT, which was a multiuser system, unlike OS/2. Plus it had an OS/2 1.3 layer, specifically so you could migrate SQL Server. So after the divorce, MS obviously didn't promote OS/2, because they had a better thing coming.
There were 3 editions of OS/2 planned:
OS/2 1.x, 16-bit, for the 80286
OS/2 2.x, 32-bit, for the 80386
OS/2 3.x, portable, for RISC and other CPU families
When MS and IBM split, IBM kept 2.x and Microsoft got 3.x.
It hired Dave Cutler and his team from DEC and gave them OS/2 3.x to complete. It was built on the Intel i860 RISC CPU, codenamed N-Ten. So this version was codenamed OS/2 NT.
Windows 3 was a big hit and Windows 3.1 even bigger, so OS/2 NT was renamed Windows NT.
Much of the world still runs it.
My recollection from interview was ... he didn't like it (OS/2), and built their own OS arch from scratch but with some OS/2 back-compat to fulfill contractual obligations.
[0] https://www.itprotoday.com/windows-client/windows-nt-and-vms...
That's not where the name comes from, but it's kind of funny.
I've installed it on 86box, and then converted the boot disk from 5 1/2" to 3 1/2" inch so I could install it on VMware and my IBM PS/2 model 80. That's another surprise I thought for sure the PS/2 drivers would be missing from the 5 1/4" disk version, but they were there!
On VMware the AT version of the PS/2 mouse driver locks the system up, but I copied the one from 6.123 and it works fine. Although there is no MS-DOS sessions working.
Also as a follow up on my 'dont waste money on a math co-processor' if you have the 'passthrough math' on 86box the dos sessions misbehave big time. Using the softfloat option for more accuate floats results in working MS-DOS. - Turns out OS/2 betas really did rely on a FPU!