Cutler's design was VMS written in (portable) C. (The VMS kernel was written in assembler.) VMS has great strengths, but hard file locks on OS components requi

Cutler's design was VMS written in (portable) C. (The VMS kernel was written in assembler.) VMS has great strengths, but hard file locks on OS components require downtime for patching. Cutler didn't foresee the avalanche of updates, and the availability collapse of "patch Tuesday." POSIX opportunistic locking was a great gift to his competition.