DEC's proprietary operating system for its VAX minicomputer; one of the seven or so environments that loom largest in hacker folklore. Many Unix fans generously concede that VMS would probably be the hacker's favorite commercial OS if Unix didn't exist; though true, this makes VMS fans furious. One major hacker gripe with VMS concerns its slowness — thus the following limerick:
There once was a system called VMS
Of cycles by no means abstemious.
It's chock-full of hacks
And runs on a VAX
And makes my poor stomach all squeamious.
— The Great Quux