down 1. adj. Not operating.
“The up escalator is down” is considered a humorous thing to
say (unless of course you were expecting to use it), and “The
elevator is down” always means “The elevator isn't
working” and never refers to what floor the elevator is on. With
respect to computers, this term has passed into the mainstream; the
extension to other kinds of machine is still confined to techies
(e.g. boiler mechanics may speak of a boiler being down).
2. go down vi. To stop functioning; usually said of the
system. The message from the
console that every hacker hates to hear from the
operator is “System going down in 5 minutes”.
3. take down, bring down vt. To deactivate purposely, usually for repair
work or PM. “I'm taking the system down to
work on that bug in the tape drive.” Occasionally one hears the word
down by itself used as a verb in this
vt. sense.
See crash; oppose
up.