:showstopper: /n./ A hardware or (especially) software bug that makes an implementation effectively unusable; one that absolutely has to be fixed before development can go on. Opposite in connotation from its original theatrical use, which refers to something stunningly *good*.
:shriek: /n./ See {excl}. Occasional CMU usage, also in common use among APL fans and mathematicians, especially category theorists.
:Shub-Internet: /shuhb' in't*r-net/ /n./ [MUD: from H. P. Lovecraft's evil fictional deity Shub-Niggurath, the Black Goat with a Thousand Young] The harsh personification of the Internet, Beast of a Thousand Processes, Eater of Characters, Avatar of Line Noise, and Imp of Call Waiting; the hideous multi-tendriled entity formed of all the manifold connections of the net. A sect of MUDders worships Shub-Internet, sacrificing objects and praying for good connections. To no avail — its purpose is malign and evil, and is the cause of all network slowdown. Often heard as in "Freela casts a tac nuke at Shub-Internet for slowing her down." (A forged response often follows along the lines of: "Shub-Internet gulps down the tac nuke and burps happily.") Also cursed by users of the Web, {FTP} and {TELNET} when the system slows down. The dread name of Shub-Internet is seldom spoken aloud, as it is said that repeating it three times will cause the being to wake, deep within its lair beneath the Pentagon.
[January 1996: It develops that one of the computer administrators in the basement of the Pentagon read this entry and fell over laughing. As a result, you too can now poke Shub-Internet by {ping}ing shub-internet.ims.disa.mil. See also {kremvax}. — ESR]
:sidecar: /n./ 1. Syn. {slap on the side}. Esp. used of add-ons for the late and unlamented IBM PCjr. 2. The IBM PC compatibility box that could be bolted onto the side of an Amiga. Designed and produced by Commodore, it broke all of the company's own design rules. If it worked with any other peripherals, it was by {magic}. 3. More generally, any of various devices designed to be connected to the expansion slot on the left side of the Amiga 500 (and later, 600 & 1200), which included a hard drive controller, a hard drive, and additional memory.
:SIG: /sig/ /n./ (also common as a prefix in combining forms)
A Special Interest Group, in one of several technical areas,
sponsored by the Association for Computing Machinery; well-known
ones include SIGPLAN (the Special Interest Group on Programming
Languages), SIGARCH (the Special Interest Group for Computer
Architecture) and SIGGRAPH (the Special Interest Group for Computer
Graphics). Hackers, not surprisingly, like to overextend this
naming convention to less formal associations like SIGBEER (at ACM
conferences) and SIGFOOD (at University of Illinois).
:sig block: /sig blok/ /n./ [Unix; often written `.sig' there] Short for `signature', used specifically to refer to the electronic signature block that most Unix mail- and news-posting software will {automagically} append to outgoing mail and news. The composition of one's sig can be quite an art form, including an ASCII logo or one's choice of witty sayings (see {sig quote}, {fool file, the}); but many consider large sigs a waste of {bandwidth}, and it has been observed that the size of one's sig block is usually inversely proportional to one's longevity and level of prestige on the net. See also {doubled sig}.
:sig quote: /sig kwoht/ /n./ [Usenet] A maxim, quote, proverb, joke, or slogan embedded in one's {sig block} and intended to convey something of one's philosophical stance, pet peeves, or sense of humor. "Calm down, it's only ones and zeroes."
:sig virus: /n./ A parasitic {meme} embedded in a {sig
block}. There was a {meme plague} or fad for these on Usenet in
late 1991. Most were equivalents of "I am a .sig virus. Please
reproduce me in your .sig block.". Of course, the .sig virus's
memetic hook is the giggle value of going along with the gag; this,
however, was a self-limiting phenomenon as more and more people
picked up on the idea. There were creative variants on it; some
people stuck `sig virus antibody' texts in their sigs, and there
was at least one instance of a sig virus eater.
:signal-to-noise ratio: [from analog electronics] /n./ Used by
hackers in a generalization of its technical meaning. `Signal'
refers to useful information conveyed by some communications
medium, and `noise' to anything else on that medium. Hence a low
ratio implies that it is not worth paying attention to the medium
in question. Figures for such metaphorical ratios are never given.
The term is most often applied to {Usenet} newsgroups during
{flame war}s. Compare {bandwidth}. See also {coefficient
of X}, {lost in the noise}.