dragon n.
[MIT] A program similar to a daemon, except that it is not invoked at all,
but is instead used by the system to perform various secondary
tasks. A typical example would be an accounting program, which
keeps track of who is logged in, accumulates load-average
statistics, etc. Under ITS, many terminals displayed a list of
people logged in, where they were, what they were running, etc.,
along with some random picture (such as a unicorn, Snoopy, or the
Enterprise), which was generated by the `name dragon'. Usage:
rare outside MIT -- under Unix and most other OSes this would be
called a `background demon' or daemon. The best-known Unix example of a dragon
is cron(1). At SAIL, they called this sort of thing
a `phantom'.
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Dragon Book n.
The classic text "Compilers: Principles, Techniques and
Tools", by Alfred V. Aho, Ravi Sethi, and Jeffrey D. Ullman
(Addison-Wesley 1986; ISBN 0-201-10088-6), so called because of
the cover design featuring a dragon labeled `complexity of
compiler design' and a knight bearing the lance `LALR parser
generator' among his other trappings. This one is more
specifically known as the `Red Dragon Book' (1986); an earlier
edition, sans Sethi and titled "Principles Of Compiler Design"
(Alfred V. Aho and Jeffrey D. Ullman; Addison-Wesley, 1977; ISBN
0-201-00022-9), was the `Green Dragon Book' (1977). (Also `New
Dragon Book', `Old Dragon Book'.) The horsed knight and the Green
Dragon were warily eying each other at a distance; now the knight
is typing (wearing gauntlets!) at a terminal showing a video-game
representation of the Red Dragon's head while the rest of the
beast extends back in normal space. See also book titles.
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drain v.
[IBM] Syn. for flush (sense 2).
Has a connotation of finality about it; one speaks of draining a
device before taking it offline.
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dread high-bit disease n.
A condition endemic to some now-obsolete computers and
peripherals (including ASR-33 teletypes and PRIME minicomputers)
that results in all characters having their high (0x80) bit
forced on. This of course makes transporting files to other
systems much more difficult, not to mention the problems these
machines have talking with true 8-bit devices.
This term was originally used specifically of PRIME (a.k.a.
PR1ME) minicomputers. Folklore has it that PRIME adopted the
reversed-8-bit convention in order to save 25 cents per serial
line per machine; PRIME old-timers, on the other hand, claim they
inherited the disease from Honeywell via customer NASA's
compatibility requirements and struggled heroically to cure it.
Whoever was responsible, this probably qualifies as one of the
most cretinous design tradeoffs
ever made. See meta bit.
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