Meta bit
The top bit of an 8-bit character, which is on in character values 128--255.
Also called
high bit,
alt bit, or
hobbit.
Some terminals and consoles (see
space-cadet keyboard) have a META shift key.
Others (including, *mirabile dictu*, keyboards on IBM PC-class machines) have an ALT key.
See also
bucky bits.
Historical note: although in modern usage shaped by a universe of 8-bit bytes the meta bit is invariably
hex 80 (
octal 0200), things were different on earlier machines with 36 bit words and 9-bit bytes.
The MIT and Stanford keyboards (see
space-cadet keyboard) generated hex 100 (octal 400) from their meta keys.
[
Jargon File]
