UP adj. 1. Working, in order. "The down escalator is up." 2. BRING UP: v. To create a working version and start it. "They brought up a down system." USER n. A programmer who will believe anything you tell him. One who asks questions. Identified at MIT with "loser" by the spelling "luser". See REAL USER. [Note by GLS: I don't agree with RF's definition at all. Basically, there are two classes of people who work with a program: there are implementors (hackers) and users (losers). The users are looked down on by hackers to a mild degree because they don't understand the full ramifications of the system in all its glory. (A few users who do are known as real winners.) It is true that users ask questions (of necessity). Very often they are annoying or downright stupid.] UUO (you-you-oh) [short for "Un-Used Operation"] n. A DEC-10 system monitor call. The term "Un-Used Operation" comes from the fact that, on DEC-10 systems, monitor calls are implemented as invalid or illegal machine instructions, which cause traps to the monitor (see TRAP). The SAIL manual describing the available UUO's has a cover picture showing an unidentified underwater object. See YOYO. [Note: DEC sales people have since decided that "Un-Used Operation" sounds bad, so UUO now stands for "Unimplemented User Operation".] Tenex and Twenex systems use the JSYS machine instruction (q.v.), which is halfway between a legal machine instruction and a UUO, since KA-10 Tenices implement it as a hardware instruction which can be used as an ordinary subroutine call (sort of a "pure JSR")