note: The instruction format of the IBM 7090 that hostedthe original LISP implementation featured two 15-bit fields called
the `address' and `decrement' parts. The term `cdr' was originally
`Contents of Decrement part of Register'. Similarly, `car' stood
for `Contents of Address part of Register'.
The cdr and car operations have since become bases for
formation of compound metaphors in non-LISP contexts. GLS recalls,
for example, a programming project in which strings were
represented as linked lists; the get-character and skip-character
operations were of course called CHAR and CHDR.
:chad: /chad/ n. 1. The perforated edge strips on printer paper, after they have been separated from the printed portion. Also called {selvage} and {perf}. 2. obs. The confetti-like paper bits punched out of cards or paper tape; this was also called `chaff', `computer confetti', and `keypunch droppings'.
Historical note: One correspondent believes `chad' (sense 2) derives from the Chadless keypunch (named for its inventor), which cut little u-shaped tabs in the card to make a hole when the tab folded back, rather than punching out a circle/rectangle; it was clear that if the Chadless keypunch didn't make them, then the stuff that other keypunches made had to be `chad'.
:chad box: n. {Iron Age} card punches contained boxes inside them, about the size of a lunchbox (or in some models a large wastebasket), that held the {chad} (sense 2). You had to open the covers of the card punch periodically and empty the chad box. The {bit bucket} was notionally the equivalent device in the CPU enclosure, which was typically across the room in another great gray-and-blue box.
:chain: 1. [orig. from BASIC's `CHAIN' statement] vi. To hand off execution to a child or successor without going through the {OS} command interpreter that invoked it. The state of the parent program is lost and there is no returning to it. Though this facility used to be common on memory-limited micros and is still widely supported for backward compatibility, the jargon usage is semi-obsolescent; in particular, most UNIX programmers will think of this as an {exec}. Oppose the more modern {subshell}. 2. A series of linked data areas within an operating system or application. `Chain rattling' is the process of repeatedly running through the linked data areas searching for one which is of interest to the executing program. The implication is that there is a very large number of links on the chain.
:channel: [IRC] n. The basic unit of discussion on {IRC}. Once one joins a channel, everything one types is read by others on that channel. Channels can either be named with numbers or with strings that begin with a `#' sign, and can have topic descriptions (which are generally irrelevant to the actual subject of discussion). Some notable channels are `#initgame', `#hottub', and `#report'. At times of international crisis, `#report' has hundreds of members, some of whom take turns listening to various news services and summarizing the news, or in some cases, giving first-hand accounts of the action (e.g., Scud missile attacks in Tel Aviv during the Gulf War in 1991).
:channel hopping: [IRC, GEnie] n. To rapidly switch channels on {IRC}, or GEnie chat board, just as a social butterfly might hop from one group to another at a party. This may derive from the TV watcher's idiom `channel surfing'.
:channel op: /chan'l op/ [IRC] n. Someone who is endowed with privileges on a particular {IRC} channel; commonly abbreviated `chanop' or `CHOP'. These privileges include the right to {kick} users, to change various status bits, and to make others into CHOPs.
:chanop: /chan'-op/ [IRC] n. See {channel op}.
:char: /keir/ or /char/; rarely, /kar/ n. Shorthand for `character'. Esp. used by C programmers, as `char' is C's typename for character data.
:charityware: /char'it-ee-weir`/ n. Syn. {careware}.
:chase pointers: 1. vi. To go through multiple levels of indirection, as in traversing a linked list or graph structure. Used esp. by programmers in C, where explicit pointers are a very common data type. This is techspeak, but it remains jargon when used of human networks. "I'm chasing pointers. Bob said you could tell me who to talk to about…." See {dangling pointer} and {snap}. 2. [Cambridge] `pointer chase' or `pointer hunt': The process of going through a dump (interactively or on a large piece of paper printed with hex {runes}) following dynamic data-structures. Used only in a debugging context.
:check: n. A hardware-detected error condition, most commonly used to refer to actual hardware failures rather than software-induced traps. E.g., a `parity check' is the result of a hardware-detected parity error. Recorded here because it's often humorously extended to non-technical problems. For example, the term `child check' has been used to refer to the problems caused by a small child who is curious to know what happens when s/he presses all the cute buttons on a computer's console (of course, this particular problem could have been prevented with {molly-guard}s).
:chemist: [Cambridge] n. Someone who wastes computer time on {number-crunching} when you'd far rather the machine were doing something more productive, such as working out anagrams of your name or printing Snoopy calendars or running {life} patterns. May or may not refer to someone who actually studies chemistry.
:Chernobyl chicken: n. See {laser chicken}.
:Chernobyl packet: /cher-noh'b*l pak'*t/ n. A network packet that
induces {network meltdown} (the result of a {broadcast
storm}), in memory of the April 1986 nuclear accident at Chernobyl
in Ukraine. The typical scenario involves an IP Ethernet datagram
that passes through a gateway with both source and destination
Ether and IP address set as the respective broadcast addresses for
the subnetworks being gated between. Compare {Christmas tree
packet}.
:chicken head: [Commodore] n. The Commodore Business Machines logo,
which strongly resembles a poultry part. Rendered in ASCII as
`C='. With the arguable exception of the Amiga (see {amoeba}),
Commodore's machines are notoriously crocky little {bitty box}es
(see also {PETSCII}). Thus, this usage may owe something to
Philip K. Dick's novel `Do Androids Dream of Electric Sheep?'
(the basis for the movie `Blade Runner'), in which a
`chickenhead' is a mutant with below-average intelligence.
:chiclet keyboard: n. A keyboard with small rectangular or lozenge-shaped rubber or plastic keys that look like pieces of chewing gum. (Chiclets is the brand name of a variety of chewing gum that does in fact resemble the keys of chiclet keyboards.) Used esp. to describe the original IBM PCjr keyboard. Vendors unanimously liked these because they were cheap, and a lot of early portable and laptop products got launched using them. Customers rejected the idea with almost equal unanimity, and chiclets are not often seen on anything larger than a digital watch any more.
:chine nual: /sheen'yu-*l/ [MIT] n.,obs. The Lisp Machine Manual, so called because the title was wrapped around the cover so only those letters showed on the front.
:Chinese
