yea, a big one. Once there was an intentionally multi-user-from-ground-up OS called "Multics". Dude named ken thompson or dennis ritchie or something worked on it but was like "bro, so bloated". So dude writes a DISK BENCHMARKING system, single user, called it "Unix" as if to castrate multics. The original unix was disk benchmarking, barebones. So we know how that moved into multi-user

source: kernighans readingbook, "unix a memoir" or something like that, great read