It's definitely true that they do not have access to the original OS/2 source - this has been confirmed by people from Arca Noae in various interviews/presentations I've seen. I've never heard a definitive explanation for why, but two reasons are usually speculated:
1) Due to the amount of third party code in OS/2 (most notably, the DOS and Win 3.x layer) that IBM is unable to license out the code, or unwilling to go to the trouble to figure out the legal implications.
As far as I know, yes. There were no changes made to eCS which required source - everything was implemented as drivers, or layers on top of the base OS.
I have not heard or seen any direct confirmation of this anywhere. If you have, I would really like to know. I am looking at a follow-on review and this would be great background info.
> most notably, the DOS and Win 3.x layer
I think what you put in parentheses here is the real reason.
IBM probably still has the source. It seems to be methodical, unlike say Symantec which lost the QEMM and DESQview source.
But IBM and MS co-developed OS/2. MS has joint ownership of this code.
MS has a 50+ year history of being a deeply dishonest and unreliable company. It hates FOSS and only releases what it has to. MS-DOS 4 only got out became someone found it and made it public.
Satnav Nutella has no more understanding of this than the Queen of England. He will do and say whatever is needed to make Number Go Up.
MS releases tiny token gestures to make the incomprehending loud FOSS advocates believe them. Notepad, Calc, ancient DOS releases... nothing that matters.
It won't release Windows 3 because some of that code is still in Windows today.
MS does not love Linux. WSL2 is an embrace-and-extend tactic. If MS had a real clue left then WSL1 would never have been a product: it would have just extended the NT kernel POSIX personality to run Linux binaries.
Remember the core of Windows is the NT kernel and it can natively run OS/2 binaries and Unix binaries.
It doesn't because MS turned it off. NT is a version of VMS with native Unix and OS/2 binary support and a GUI built on Windows 3 code and MS won't let that code out. If it did the ReactOS people could make a ReactOS that was Good Enough. The WINE people could make a seamless one that make .EXEs a 1st class Linux citizen.
MS is terrified of that because it doesn't have the skills to do the equivalent any more, and WSL2 is the existence proof of that. It couldn't even get systemd working in WSL2 until it hired Poettering to do it. Then he stayed there just long enough to get the money and he's off out again.
The reason IBM won't release the OS/2 source, even to Arca Noae, is Microsoft.
Also, around the 25 minute mark, Rosenthal points out that the Workplace Shell source code "no longer exists in one place anymore", so I do think that there are problems with finding all the source for the OS.
Seems to ve very weird that IBM will give them a license to keep OS/2 updated but no access to the kernel.