:daemon book: /n./ "The Design and Implementation of the 4.3BSD UNIX Operating System", by Samuel J. Leffler, Marshall Kirk McKusick, Michael J. Karels, and John S. Quarterman (Addison-Wesley Publishers, 1989, ISBN 0-201-06196-1) — the standard reference book on the internals of {BSD} Unix. So called because the cover has a picture depicting a little devil (a visual play on {daemon}) in sneakers, holding a pitchfork (referring to one of the characteristic features of Unix, the `fork(2)' system call). Also known as the {Devil Book}.
:dahmum: /dah'mum/ /n./ [Usenet] The material of which
protracted {flame war}s, especially those about operating
systems, is composed. Homeomorphic to {spam}. The term
`dahmum' is derived from the name of a militant {OS/2}
advocate, and originated when an extensively crossposted
OS/2-versus-{Linux} debate was fed through {Dissociated
Press}.
:dangling pointer: /n./ A reference that doesn't actually lead
anywhere (in C and some other languages, a pointer that doesn't
actually point at anything valid). Usually this happens because it
formerly pointed to something that has moved or disappeared. Used
as jargon in a generalization of its techspeak meaning; for
example, a local phone number for a person who has since moved to
the other coast is a dangling pointer. Compare {dead link}.
:dark-side hacker: /n./ A criminal or malicious hacker; a {cracker}. From George Lucas's Darth Vader, "seduced by the dark side of the Force". The implication that hackers form a sort of elite of technological Jedi Knights is intended. Oppose {samurai}.
:Datamation: /day`t*-may'sh*n/ /n./ A magazine that many hackers assume all {suit}s read. Used to question an unbelieved quote, as in "Did you read that in `Datamation?'" (But see below; this slur may be dated by the time you read this.) It used to publish something hackishly funny every once in a while, like the original paper on {COME FROM} in 1973, and Ed Post's "Real Programmers Don't Use Pascal" ten years later, but for a long time after that it was much more exclusively {suit}-oriented and boring. Following a change of editorship in 1994, Datamation is trying for more of the technical content and irreverent humor that marked its early days.
Datamation now has a WWW page at http://www.datamation.com
worth visiting for its selection of computer humor, including
"Real Programmers Don't Use Pascal" and the `Bastard Operator
From Hell' stories by Simon Travaglia (see {BOFH}).
:DAU: /dow/ [German FidoNet] /n./ German acronym for D"ummster Anzunehmender User (stupidest imaginable user). From the engineering-slang GAU for Gr"osster Anzunehmender Unfall, worst assumable accident, esp. of a LNG tank farm plant or something with similarly disastrous consequences. In popular German, GAU is used only to refer to worst-case nuclear acidents such as a core meltdown. See {cretin}, {fool}, {loser} and {weasel}.
:day mode: /n./ See {phase} (sense 1). Used of people only.
:dd: /dee-dee/ /vt./ [Unix: from IBM {JCL}] Equivalent to {cat} or {BLT}. Originally the name of a Unix copy command with special options suitable for block-oriented devices; it was often used in heavy-handed system maintenance, as in "Let's `dd' the root partition onto a tape, then use the boot PROM to load it back on to a new disk". The Unix `dd(1)' was designed with a weird, distinctly non-Unixy keyword option syntax reminiscent of IBM System/360 JCL (which had an elaborate DD `Dataset Definition' specification for I/O devices); though the command filled a need, the interface design was clearly a prank. The jargon usage is now very rare outside Unix sites and now nearly obsolete even there, as `dd(1)' has been {deprecated} for a long time (though it has no exact replacement). The term has been displaced by {BLT} or simple English `copy'.
:DDT: /D-D-T/ /n./ 1. Generic term for a program that assists in debugging other programs by showing individual machine instructions in a readable symbolic form and letting the user change them. In this sense the term DDT is now archaic, having been widely displaced by `debugger' or names of individual programs like `adb', `sdb', `dbx', or `gdb'. 2. [ITS] Under MIT's fabled {{ITS}} operating system, DDT (running under the alias HACTRN, a six-letterism for `Hack Translator') was also used as the {shell} or top level command language used to execute other programs. 3. Any one of several specific DDTs (sense 1) supported on early {DEC} hardware. The DEC PDP-10 Reference Handbook (1969) contained a footnote on the first page of the documentation for DDT that illuminates the origin of the term: