Chapter 56

1. An unspecified but usually well-understood time, often used in conjunction with a later time T+1. "We'll meet on campus at time T or at Louie's at time T+1" means, in the context of going out for dinner: "We can meet on campus and go to Louie's, or we can meet at Louie's itself a bit later." (Louie's was a Chinese restaurant in Palo Alto that was a favorite with hackers.) Had the number 30 been used instead of the number 1, it would have implied that the travel time from campus to Louie's is 30 minutes; whatever time T is (and that hasn't been decided on yet), you can meet half an hour later at Louie's than you could on campus and end up eating at the same time. See also since time T equals minus infinity.

Node:times-or-divided-by, Next:TINC, Previous:time T, Up:= T =

times-or-divided-by quant.

[by analogy with `plus-or-minus'] Term occasionally used when describing the uncertainty associated with a scheduling estimate, for either humorous or brutally honest effect. For a software project, the scheduling uncertainty factor is usually at least 2.

Node:TINC, Next:Tinkerbell program, Previous:times-or-divided-by, Up:= T =

TINC //

[Usenet] Abbreviation: "There Is No Cabal". See backbone cabal and NANA, but note that this abbreviation did not enter use until long after the dispersal of the backbone cabal.

Node:Tinkerbell program, Next:TINLC, Previous:TINC, Up:= T =

Tinkerbell program n.

[Great Britain] A monitoring program used to scan incoming network calls and generate alerts when calls are received from particular sites, or when logins are attempted using certain IDs. Named after `Project Tinkerbell', an experimental phone-tapping program developed by British Telecom in the early 1980s.

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TINLC //

Abbreviation: "There Is No Lumber Cartel". See Lumber Cartel. TINLC is a takeoff on TINC.

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tip of the ice-cube n. //

[IBM] The visible part of something small and insignificant. Used as an ironic comment in situations where `tip of the iceberg' might be appropriate if the subject were at all important.

Node:tired iron, Next:tits on a keyboard, Previous:tip of the ice-cube, Up:= T =

tired iron n.

[IBM] Hardware that is perfectly functional but far enough behind the state of the art to have been superseded by new products, presumably with sufficient improvement in bang-per-buck that the old stuff is starting to look a bit like a dinosaur.

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tits on a keyboard n.

Small bumps on certain keycaps to keep touch-typists registered. Usually on the 5 of a numeric keypad, and on the F and J of a QWERTY keyboard; but older Macs, perverse as usual, had them on the D and K keys (this changed in 1999).

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TLA /T-L-A/ n.

[Three-Letter Acronym] 1. Self-describing abbreviation for a species with which computing terminology is infested. 2. Any confusing acronym. Examples include MCA, FTP, SNA, CPU, MMU, SCCS, DMU, FPU, NNTP, TLA. People who like this looser usage argue that not all TLAs have three letters, just as not all four-letter words have four letters. One also hears of `ETLA' (Extended Three-Letter Acronym, pronounced /ee tee el ay/) being used to describe four-letter acronyms. The term `SFLA' (Stupid Four-Letter Acronym) has also been reported. See also YABA.

The self-effacing phrase "TDM TLA" (Too Damn Many...) is often used to bemoan the plethora of TLAs in use. In 1989, a random of the journalistic persuasion asked hacker Paul Boutin "What do you think will be the biggest problem in computing in the 90s?" Paul's straight-faced response: "There are only 17,000 three-letter acronyms." (To be exact, there are 26^3 = 17,576.) There is probably some karmic justice in the fact that Paul Boutin subsequently became a journalist.

Node:(TM), Next:TMRC, Previous:TLA, Up:= T =

(TM) //

[Usenet] ASCII rendition of the trademark-superscript symbol appended to phrases that the author feels should be recorded for posterity, perhaps in future editions of this lexicon. Sometimes used ironically as a form of protest against the recent spate of software and algorithm patents and `look and feel' lawsuits. See also UN*X.

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TMRC /tmerk'/ n.

The Tech Model Railroad Club at MIT, one of the wellsprings of hacker culture. The 1959 "Dictionary of the TMRC Language" compiled by Peter Samson included several terms that became basics of the hackish vocabulary (see esp. foo, mung, and frob).

By 1962, TMRC's legendary layout was already a marvel of complexity and has grown in the years since. All the features described here were still present when the old layout was decomissioned in 1998 just before the demolition of MIT Building 20, and will almost certainly be retained when the old layout is rebuilt (expected in 2003). The control system alone featured about 1200 relays. There were scram switches located at numerous places around the room that could be thwacked if something undesirable was about to occur, such as a train going full-bore at an obstruction. Another feature of the system was a digital clock on the dispatch board, which was itself something of a wonder in those bygone days before cheap LEDs and seven-segment displays. When someone hit a scram switch the clock stopped and the display was replaced with the word `FOO'; at TMRC the scram switches are therefore called `foo switches'.

Steven Levy, in his book "Hackers" (see the Bibliography in Appendix C), gives a stimulating account of those early years. TMRC's Signals and Power Committee included many of the early PDP-1 hackers and the people who later became the core of the MIT AI Lab staff. Thirty years later that connection is still very much alive, and this lexicon accordingly includes a number of entries from a recent revision of the TMRC dictionary.

TMRC has a web page at http://web.mit.edu/tmrc/www/.

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TMRCie /tmerk'ee/, n.

[MIT] A denizen of TMRC.

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TMTOWTDI /tim-toh'-dee/

There's More Than One Way To Do It. This abbreviation of the official motto of Perl is frequently used on newsgroups and mailing lists related to that language.

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to a first approximation adj.

1. [techspeak] When one is doing certain numerical computations, an approximate solution may be computed by any of several heuristic methods, then refined to a final value. By using the starting point of a first approximation of the answer, one can write an algorithm that converges more quickly to the correct result. 2. In jargon, a preface to any comment that indicates that the comment is only approximately true. The remark "To a first approximation, I feel good" might indicate that deeper questioning would reveal that not all is perfect (e.g., a nagging cough still remains after an illness).

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to a zeroth approximation

[from `to a first approximation'] A really sloppy approximation; a wild guess. Compare social science number.

Node:toad, Next:toast, Previous:to a zeroth approximation, Up:= T =

toad vt. [MUD]

1. Notionally, to change a MUD player into a toad. 2. To permanently and totally exile a player from the MUD. A very serious action, which can only be done by a MUD wizard; often involves a lot of debate among the other characters first. See also frog, FOD.

Node:toast, Next:toaster, Previous:toad, Up:= T =

toast 1. n.

Any completely inoperable system or component, esp. one that has just crashed and burned: "Uh, oh ... I think the serial board is toast." 2. vt. To cause a system to crash accidentally, especially in a manner that requires manual rebooting. "Rick just toasted the firewall machine again." Compare fried.

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toaster n.

1. The archetypal really stupid application for an embedded microprocessor controller; often used in comments that imply that a scheme is inappropriate technology (but see elevator controller). "DWIM for an assembler? That'd be as silly as running Unix on your toaster!" 2. A very, very dumb computer. "You could run this program on any dumb toaster." See bitty box, Get a real computer!, toy, beige toaster. 3. A Macintosh, esp. the Classic Mac. Some hold that this is implied by sense 2. 4. A peripheral device. "I bought my box without toasters, but since then I've added two boards and a second disk drive." 5. A specialized computer used as an appliance. See web toaster, video toaster.

Node:toeprint, Next:toggle, Previous:toaster, Up:= T =

toeprint n.

A footprint of especially small size.

Node:toggle, Next:tool, Previous:toeprint, Up:= T =

toggle vt.

To change a bit from whatever state it is in to the other state; to change from 1 to 0 or from 0 to 1. This comes from `toggle switches', such as standard light switches, though the word `toggle' actually refers to the mechanism that keeps the switch in the position to which it is flipped rather than to the fact that the switch has two positions. There are four things you can do to a bit: set it (force it to be 1), clear (or zero) it, leave it alone, or toggle it. (Mathematically, one would say that there are four distinct boolean-valued functions of one boolean argument, but saying that is much less fun than talking about toggling bits.)

Node:tool, Next:toolsmith, Previous:toggle, Up:= T =

tool 1. n.

A program used primarily to create, manipulate, modify, or analyze other programs, such as a compiler or an editor or a cross-referencing program. Oppose app, operating system. 2. [Unix] An application program with a simple, `transparent' (typically text-stream) interface designed specifically to be used in programmed combination with other tools (see filter, plumbing). 3. [MIT: general to students there] vi. To work; to study (connotes tedium). The TMRC Dictionary defined this as "to set one's brain to the grindstone". See hack. 4. n. [MIT] A student who studies too much and hacks too little. (MIT's student humor magazine rejoices in the name "Tool and Die".)

Node:toolsmith, Next:toor, Previous:tool, Up:= T =

toolsmith n.

The software equivalent of a tool-and-die specialist; one who specializes in making the tools with which other programmers create applications. Many hackers consider this more fun than applications per se; to understand why, see uninteresting. Jon Bentley, in the "Bumper-Sticker Computer Science" chapter of his book "More Programming Pearls", quotes Dick Sites from DEC as saying "I'd rather write programs to write programs than write programs".

Node:toor, Next:topic drift, Previous:toolsmith, Up:= T =

toor n.

The Bourne-Again Super-user. An alternate account with UID of 0, created on Unix machines where the root user has an inconvenient choice of shell. Compare avatar.

Node:topic drift, Next:topic group, Previous:toor, Up:= T =

topic drift n.

Term used on GEnie, Usenet and other electronic fora to describe the tendency of a thread to drift away from the original subject of discussion (and thus, from the Subject header of the originating message), or the results of that tendency. The header in each post can be changed to keep current with the posts, but usually isn't due to forgetfulness or laziness. A single post may often result in several posts each responding to a different point in the original. Some subthreads will actually be in response to some off-the-cuff side comment, possibly degenerating into a flame war, or just as often evolving into a separate discussion. Hence, discussions aren't really so much threads as they are trees. Except that they don't really have leaves, or multiple branching roots; usually some lines of discussion will just sort of die off after everyone gets tired of them. This could take anywhere from hours to weeks, or even longer.

The term `topic drift' is often used in gentle reminders that the discussion has strayed off any useful track. "I think we started with a question about Niven's last book, but we've ended up discussing the sexual habits of the common marmoset. Now that's topic drift!"

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topic group n.

Syn. forum.

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TOPS-10 /tops-ten/ n.

DEC's proprietary OS for the fabled PDP-10 machines, long a favorite of hackers but now effectively extinct. A fountain of hacker folklore; see Appendix A. See also ITS, TOPS-20, TWENEX, VMS, operating system. TOPS-10 was sometimes called BOTS-10 (from `bottoms-ten') as a comment on the inappropriateness of describing it as the top of anything.

Node:TOPS-20, Next:tourist, Previous:TOPS-10, Up:= T =

TOPS-20 /tops-twen'tee/ n.

See TWENEX.

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tourist n.

1. [ITS] A guest on the system, especially one who generally logs in over a network from a remote location for comm mode, email, games, and other trivial purposes. One step below luser. ITS hackers often used to spell this turist, perhaps by some sort of tenuous analogy with luser (this usage may also have expressed the ITS culture's penchant for six-letterisms, and-or been some sort of tribute to Alan Turing). Compare twink, lurker, read-only user. 2. [IRC] An IRC user who goes from channel to channel without saying anything; see channel hopping.

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tourist information n.

Information in an on-line display that is not immediately useful, but contributes to a viewer's gestalt of what's going on with the software or hardware behind it. Whether a given piece of info falls in this category depends partly on what the user is looking for at any given time. The `bytes free' information at the bottom of an MS-DOS dir display is tourist information; so (most of the time) is the TIME information in a Unix ps(1) display.

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touristic adj.

Having the quality of a tourist. Often used as a pejorative, as in `losing touristic scum'. Often spelled `turistic' or `turistik', so that phrase might be more properly rendered `lusing turistic scum'.

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toy n.

A computer system; always used with qualifiers. 1. `nice toy': One that supports the speaker's hacking style adequately. 2. `just a toy': A machine that yields insufficient computrons for the speaker's preferred uses. This is not condemnatory, as is bitty box; toys can at least be fun. It is also strongly conditioned by one's expectations; Cray XMP users sometimes consider the Cray-1 a `toy', and certainly all RISC boxes and mainframes are toys by their standards. See also Get a real computer!.

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toy language n.

A language useful for instructional purposes or as a proof-of-concept for some aspect of computer-science theory, but inadequate for general-purpose programming. Bad Things can result when a toy language is promoted as a general purpose solution for programming (see bondage-and-discipline language); the classic example is Pascal. Several moderately well-known formalisms for conceptual tasks such as programming Turing machines also qualify as toy languages in a less negative sense. See also MFTL.

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toy problem n.

[AI] A deliberately oversimplified case of a challenging problem used to investigate, prototype, or test algorithms for a real problem. Sometimes used pejoratively. See also gedanken, toy program.

Node:toy program, Next:trampoline, Previous:toy problem, Up:= T =

toy program n.

1. One that can be readily comprehended; hence, a trivial program (compare noddy). 2. One for which the effort of initial coding dominates the costs through its life cycle. See also noddy.

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trampoline n.

An incredibly hairy technique, found in some HLL and program-overlay implementations (e.g., on the Macintosh), that involves on-the-fly generation of small executable (and, likely as not, self-modifying) code objects to do indirection between code sections. Under BSD and possibly in other Unixes, trampoline code is used to transfer control from the kernel back to user mode when a signal (which has had a handler installed) is sent to a process. hese pieces of live data are called `trampolines'. Trampolines are notoriously difficult to understand in action; in fact, it is said by those who use this term that the trampoline that doesn't bend your brain is not the true trampoline. See also snap.

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trap

1. n. A program interrupt, usually an interrupt caused by some exceptional situation in the user program. In most cases, the OS performs some action, then returns control to the program. 2. vi. To cause a trap. "These instructions trap to the monitor." Also used transitively to indicate the cause of the trap. "The monitor traps all input/output instructions."

This term is associated with assembler programming (`interrupt' or `exception' is more common among HLL programmers) and appears to be fading into history among programmers as the role of assembler continues to shrink. However, it is still important to computer architects and systems hackers (see system, sense 1), who use it to distinguish deterministically repeatable exceptions from timing-dependent ones (such as I/O interrupts).

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trap door n.

(alt. `trapdoor') 1. Syn. back door -- a Bad Thing. 2. [techspeak] A `trap-door function' is one which is easy to compute but very difficult to compute the inverse of. Such functions are Good Things with important applications in cryptography, specifically in the construction of public-key cryptosystems.

Node:trash, Next:trawl, Previous:trap door, Up:= T =

trash vt.

To destroy the contents of (said of a data structure). The most common of the family of near-synonyms including mung, mangle, and scribble.

Node:trawl, Next:tree-killer, Previous:trash, Up:= T =

trawl v.

To sift through large volumes of data (e.g., Usenet postings, FTP archives, or the Jargon File) looking for something of interest.

Node:tree-killer, Next:treeware, Previous:trawl, Up:= T =

tree-killer n.

[Sun] 1. A printer. 2. A person who wastes paper. This epithet should be interpreted in a broad sense; `wasting paper' includes the production of spiffy but content-free documents. Thus, most suits are tree-killers. The negative loading of this term may reflect the epithet `tree-killer' applied by Treebeard the Ent to the Orcs in J.R.R. Tolkien's "Lord of the Rings" (see also elvish, elder days).

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treeware /tree'weir/ n.

Printouts, books, and other information media made from pulped dead trees. Compare tree-killer, see documentation.

Node:trit, Next:trivial, Previous:treeware, Up:= T =

trit /trit/ n.

[by analogy with `bit'] One base-3 digit; the amount of information conveyed by a selection among one of three equally likely outcomes (see also bit). Trits arise, for example, in the context of a flag that should actually be able to assume three values -- such as yes, no, or unknown. Trits are sometimes jokingly called `3-state bits'. A trit may be semi-seriously referred to as `a bit and a half', although it is linearly equivalent to 1.5849625 bits (that is, log2(3) bits).

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trivial adj.

1. Too simple to bother detailing. 2. Not worth the speaker's time. 3. Complex, but solvable by methods so well known that anyone not utterly cretinous would have thought of them already. 4. Any problem one has already solved (some claim that hackish `trivial' usually evaluates to `I've seen it before'). Hackers' notions of triviality may be quite at variance with those of non-hackers. See nontrivial, uninteresting.

The physicist Richard Feynman, who had the hacker nature to an amazing degree (see his essay "Los Alamos From Below" in "Surely You're Joking, Mr. Feynman!"), defined `trivial theorem' as "one that has already been proved".

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troff /T'rof/ or /trof/ n.

[Unix] The gray eminence of Unix text processing; a formatting and phototypesetting program, written originally in PDP-11 assembler and then in barely-structured early C by the late Joseph Ossanna, modeled after the earlier ROFF which was in turn modeled after the Multics and CTSS program RUNOFF by Jerome Saltzer (that name came from the expression "to run off a copy"). A companion program, nroff, formats output for terminals and line printers.

In 1979, Brian Kernighan modified troff so that it could drive phototypesetters other than the Graphic Systems CAT. His paper describing that work ("A Typesetter-independent troff," AT&T CSTR #97) explains troff's durability. After discussing the program's "obvious deficiencies -- a rebarbative input syntax, mysterious and undocumented properties in some areas, and a voracious appetite for computer resources" and noting the ugliness and extreme hairiness of the code and internals, Kernighan concludes:

None of these remarks should be taken as denigrating Ossanna's accomplishment with TROFF. It has proven a remarkably robust tool, taking unbelievable abuse from a variety of preprocessors and being forced into uses that were never conceived of in the original design, all with considerable grace under fire.

The success of TeX and desktop publishing systems have reduced troff's relative importance, but this tribute perfectly captures the strengths that secured troff a place in hacker folklore; indeed, it could be taken more generally as an indication of those qualities of good programs that, in the long run, hackers most admire.

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troglodyte n.

[Commodore] 1. A hacker who never leaves his cubicle. The term `gnoll' (from Dungeons & Dragons) is also reported. 2. A curmudgeon attached to an obsolescent computing environment. The combination `ITS troglodyte' was flung around some during the Usenet and email wringle-wrangle attending the 2.x.x revision of the Jargon File; at least one of the people it was intended to describe adopted it with pride.

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troglodyte mode n.

[Rice University] Programming with the lights turned off, sunglasses on, and the terminal inverted (black on white) because you've been up for so many days straight that your eyes hurt (see raster burn). Loud music blaring from a stereo stacked in the corner is optional but recommended. See larval stage, hack mode.

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Trojan horse n.

[coined by MIT-hacker-turned-NSA-spook Dan Edwards] A malicious, security-breaking program that is disguised as something benign, such as a directory lister, archiver, game, or (in one notorious 1990 case on the Mac) a program to find and destroy viruses! See back door, virus, worm, phage, mockingbird.

Node:troll, Next:Troll-O-Meter, Previous:Trojan horse, Up:= T =

troll v.,n.