[skissane]

I think Microsoft was a lot more restrictive with source licenses - generally only universities for research purposes (and Windows Research Kernel was never the full OS anyway), some ISVs with specially negotiated deals, and some government agencies. The average customer couldn’t get access to the source code. Whereas, OpenVMS for example, I think basically any licensee could order the source.

[wazoox]

NT 3.5 and 4.0 on 4 (IIRC) and 8 processors machines required to be compiled from source on the target host, the shipping kernel only supporting 2 processors and cross-compilation not being an option. Fun times :)

[skissane]

Recompile the whole OS or just the HAL?

Why wouldn’t cross-compilation be an option?

[wazoox]

IIRC you had to recompile the Kernel and the HAL. I don't remember the details but compiling on anything but the very machine targeted wasn't practical.