[Myrddin]

Linus started with the Minix created by Doug Comer. Over time and interacting with the UNIX academic community, the starter Minix grew more like UNIX with the most leading edge features from the frontline UNIX academicians. The gcc compiler from Richard Stallman made a HUGE difference in converting all the K&R C source code to fully prototyped ANSI style C. Lots of old demons were flushed out of the code. The valgrind tool took a prominent position as a "purify" work-alike for open source. It has been fun watching the code base mature and improve. It's a much better product than the proprietary builds on UNIX on proprietary architectures. The only real "win" with the proprietary builds was avoiding the need to cater to broad hardware offerings in a single release. The counter to that is the code that can operate reliably in a heterogeneous hardware world is likely cleaner code.

[dmcnash]

Correction:
Andrew S. Tanenbaum published Minix in “Operating Systems”, Douglas Comer, Xinu, a similar idea. The way things work is most of the work creating both was done by graduate students under their direction.