The problem as far as I know is not Microsoft but all the other companies IBM used as contractors.
Many of them don't even exist any more so finding out who owns rights might be a nightmare.
Seems a bit surprising that the kernel used contractors, device drivers yes.
When the OS/2 kernel source was leaked (20 years ago?) the people I talked to told me they were able to build and use everything that was there. They also told me that according to text in the code there was a lot of subcontractors that kept their copyright. It was not like a Linux kernel where everything has the same license.
Interesting.
I remember hearing rumours that the PowerPC version of OS/2 didn't have as many licensing problems and IBM even considered open sourcing it. It would have needed device drivers, network stack etc as well as an LX loader to run regular OS/2 programs. If it had been released with a good license at the right time, who knows where it may have gone.
If IBM still have some big customers with OS/2 installations they support then they definitely have the code and the tools to build it. Not that many people know how to build it though.
I remember Scott saying what a bitch it was to build, and he was the kernel maintainer.
I've also heard rumors that, yes some big customers (banks?) did have the source.
Yes, the divide between kernel and device drivers makes it easier to support more modern hardware. Less stuff in the kernel makes it easier to expand it from the outside.
But in the end, without open source it will fail, it's quite amazing that modern CPU's still supports 30+ years old code. The only way to save anything imho is to use the Linux kernel and build a "personality" on top. But there are no resources nor business case any more.
Well the last kernel updates were more like 20 years age. They included supporting SSE etc and fixed some timing issues to boot on what then was modern hardware, they seem to have future proofed it enough that the later kernels can still boot on fairly modern hardware. My Warp 4 install still boots on my 7th generation I5, WPS fails to load though.
The ReactOS kernel would maybe be a better choice to support OS/2. NT did start as OS/2 v3 NT, supported OS/2 1.x binaries up to Win2k or XP and I had a Byte issue, from perhaps '94, with a little news article about MS getting the 2.x Presentation Manager running on NT.