:screaming tty: [UNIX] n. A terminal line which spews an infinite
number of random characters at the operating system. This can
happen if the terminal is either disconnected or connected to a
powered-off terminal but still enabled for login; misconfiguration,
misimplementation, or simple bad luck can start such a terminal
screaming. A screaming tty or two can seriously degrade the
performance of a vanilla UNIX system; the arriving "characters"
are treated as userid/password pairs and tested as such. The UNIX
password encryption algorithm is designed to be computationally
intensive in order to foil brute-force crack attacks, so although
none of the logins succeeds; the overhead of rejecting them all can
be substantial.
-- The AI Hackers Dictionary