WAITSWAITS was a variant of the Digital Equipment Corporation's TOPS-10 operating system for the PDP-10 mainframe computer, used at the Stanford Artificial Intelligence Laboratory (SAIL) up until 1990; the mainframe computer it ran on also went by the name of "SAIL".
There was never an "official" expansion of WAITS (the name itself having been arrived at by a rather sideways process), but it was frequently glossed as "West-coast Alternative to ITS". Though WAITS was less visible than ITS, there was frequent exchange of people and ideas between the two communities, and innovations pioneered at WAITS exerted enormous indirect influence.
The early screen modes of EMACS, for example, were directly inspired by WAITS' "E" editor -- one of a family of editors that were the first to do real-time editing, in which the editing commands were invisible and where one typed text at the point of insertion/overwriting. The modern style of multi-region windowing is said to have originated there. The system also featured an unusual level of support for what is now called multimedia computing, allowing analog audio and video signals to be switched to programming terminals. Also invented there were "bucky bits" - thus, the "Alt" key on every IBM PC is a WAITS legacy. One WAITS feature very notable in pre-Web days was a news-wire interface that allowed WAITS hackers to read, store, and filter AP and UPI dispatches from their terminals.
Original text from the Jargon File Version 4.3.3, September 20, 2002, used by permission.