TOPS-10
/tops-ten/ DEC's proprietary OS for the fabled {PDP-10}
machines, long a favourite of hackers but now effectively
extinct. A fountain of hacker folklore. See also {ITS},
{TOPS-20}, {TWENEX}, {VMS}, {operating system}. TOPS-10 was
sometimes called BOTS-10 (from "bottoms-ten") as a comment on
the inappropriateness of describing it as the top of anything.
[{Jargon File}]