<convention, data> A string unique to a time duration of 24
	hours between 2 successive midnights defined by the local time
	zone.  The specific representation of a date will depend on
	which calendar convention is in force; e.g., Gregorian,
	Islamic, Japanese, Chinese, Hebrew etc. as well as local
	ordering conventions such as UK: day/month/year, US:
	month/day/year.

	Inputting and outputting dates on computers is greatly
	complicated by these {localisation} issues which is why they
	tend to operate on dates internally in some unified form such
	as seconds past midnight at the start of the first of January
	1970.

	Many software and hardware representations of dates allow only
	two digits for the year, leading to the {year 2000} problem.

	{Unix manual page}: date(1), ctime(3).

	(1997-07-11)

1. <database, information science> A user's (or {agent}'s)
	request for information, generally as a formal request to a
	{database} or {search engine}.

	{SQL} is the most common {database query language}.

	2. <character> {question mark}.

	(1997-04-09)

<database> A collection of {records} in a {relational database}.

	(1997-06-04)

1. <programming> The prototype for an {object} in an
	{object-oriented language}; analogous to a {derived type} in a
	{procedural language}.  A class may also be considered to be a
	set of objects which share a common structure and behaviour.
	The structure of a class is determined by the {class
	variables} which represent the {state} of an object of that
	class and the behaviour is given by a set of {methods}
	associated with the class.

	Classes are related in a {class hierarchy}.  One class may be
	a specialisation (a "{subclass}") of another (one of its
	"{superclasses}") or it may be composed of other classes or it
	may use other classes in a {client-server} relationship.  A
	class may be an {abstract class} or a {concrete class}.

	See also {signature}.

	2. <programming> See {type class}.

	3. <networking> One of three types of {Internet addresses}
	distinguished by their most significant bits.

	3. <language> A language developed by the {Andrew Project}.
	It was one of the first attempts to add {object-oriented}
	features to {C}.

	(1995-05-01)

1. <programming> {fill-out form}.

	2. <library> (Xforms) A {GUI} component library for {X11}.

	(1998-03-24)

1. <operating system> (Or "erase") To make a file
	inaccessible.

	Usually this operation only deletes information from the
	tables the {file system} uses to locate named files; the
	file's contents still exist on {disk} and can sometimes be
	recovered by scanning the whole disk for strings which are
	known to have been in the file.  Files created subsequently on
	the same disk are quite likely to reuse the same blocks and
	thus overwrite the deleted file's data permanently.

	2. <character> The {control character} with {ASCII} code 127.
	Usually entering this character from the keyboard deletes the
	last character typed from the {input buffer}.  Sadly there is
	great confusion between {operating systems} and keyboard
	manufacturers as to whether this function should be assigned
	to the delete or {backspace} key/character.

	The choice of code 127 (binary 1111111) is not arbitrary but
	dates back to the use of {paper tape} for input.  The delete
	key rewound the tape by one character and punched out all
	seven holes, thus obliterating whatever character was there
	before.  The tape reading software ignored any delete
	characters in the input.

	(1996-12-01)

<data, database> An area of a {database} {record}, or
	{graphical user interface} {form}, into which a particular
	item of data is entered.

	Example usage: "The telephone number field is not really a
	numerical field", "Why do we need a four-digit field for the
	year?".

	A {database} {column} is the set of all instances of a given
	field from all records in a {table}.

	(1999-04-26)

<programming> One of a sequence of copies of a program, each
	incorporating new modifications.  Each version is usually
	identified by a number, commonly of the form X.Y where X is
	the major version number and Y is the release number.
	Typically an increment in X (with Y reset to zero) signifies a
	substantial increase in the function of the program or a
	partial or total re-implementation, whereas Y increases each
	time the progam is changed in any way and re-released.

	Version numbers are useful so that the user can know if the
	program has changed ({bugs} have been fixed or new functions
	added) since he obtained his copy and the programmer can tell
	if a bug report relates to the current version.  It is thus
	always important to state the version when reporting bugs.
	Statements about compatibility between different software
	components should always say which versions they apply to.

	See {change management}.

	(1997-12-07)

<jargon> A {marketroid} term for something he wants to sell
	you without bothering you with the often dizzying distinctions
	between {hardware}, {software}, {services}, {applications},
	{file formats}, companies, brand names and {operating
	systems}.

	"{Flash} is a perfect image-streaming solution."  "What is
	it?"  "Um...  about a thousand dollars."

	See also: {technology}.

	(1998-07-07)

1. <mathematics> (Or "map", "mapping") If D and C are sets
	(the domain and codomain) then a function f from D to C,
	normally written "f : D -> C" is a subset of D x C such that:

	1. For each d in D there exists some c in C such that (d,c) is
	an element of f.  I.e. the function is defined for every
	element of D.

	2. For each d in D, c1 and c2 in C, if both (d,c1) and (d,c2)
	are elements of f then c1 = c2.  I.e. the function is uniquely
	defined for every element of D.

	See also {image}, {inverse}, {partial function}.

	2. <programming> Computing usage derives from the mathematical
	term but is much less strict.  In programming (except in
	{functional programming}), a function may return different
	values each time it is called with the same argument values
	and may have {side effects}.

	A {procedure} is a function which returns no value but has
	only {side-effects}.  The {C} language, for example, has no
	procedures, only functions.  {ANSI C} even defines a {type},
	{void}, for the result of a function that has no result.

	(1996-09-01)

1. A discrepancy between a computed, observed, or measured
	value or condition and the true, specified, or theoretically
	correct value or condition.

	2. <programming> A mental mistake made by a programmer that
	may result in a program {fault}.

	3. (verb) What a program does when it stops as result of a
	programming error.

	(2000-03-28)

1. Not simulated.  Often used as a specific antonym to
	{virtual} in any of its jargon senses.

	2. <mathematics> {real number}.

	[{Jargon File}]

	(1997-03-12)

<messaging> /yoos'net/ or /yooz'net/ (Or "Usenet news", from
	"Users' Network") A distributed {bulletin board} system and
	the people who post and read articles thereon.  Originally
	implemented in 1979 - 1980 by Steve Bellovin, Jim Ellis, Tom
	Truscott, and Steve Daniel at Duke University, and supported
	mainly by {Unix} machines, it swiftly grew to become
	international in scope and, before the advent of the
	{World-Wide Web}, probably the largest decentralised
	information utility in existence.

	Usenet encompasses government agencies, universities, high
	schools, businesses of all sizes, and home computers of all
	descriptions.  In the beginning, not all Usenet hosts were on
	the Internet.  As of early 1993, it hosted over 1200
	{newsgroups} ("groups" for short) and an average of 40
	megabytes (the equivalent of several thousand paper pages) of
	new technical articles, news, discussion, chatter, and
	{flamage} every day.  By November 1999, the number of groups
	had grown to over 37,000.

	To join in you originally needed a {news reader} program but
	there are now several web gateways such as {Deja
	(http://www.deja.com/)}.  Several {web browsers} include news
	readers and {URLs} beginning "news:" refer to Usenet
	newsgroups.

	{Network News Transfer Protocol} is a {protocol} used to
	transfer news articles between a news {server} and a {news
	reader}.  The {uucp} {protocol} was sometimes used to transfer
	articles between servers, though this is probably rare now
	that most sites are on the {Internet}.

	{Stanford University} runs a service to send news articles by
	{electronic mail}.  Send electronic mail to
	<netnews@db.stanford.edu> with "help" in the message body.
	[Still?  URL?]

	{(http://www.openmarket.com/info/internet-index/current-sources.html)}.

	{Notes on news
	(http://www.ifi.uio.no/~larsi/notes/notes.html)} by Lars Magne
	Ingebrigtsen <larsi@ifi.uio.no>.

	[Gene Spafford <spaf@cs.purdue.edu>, "What is Usenet?",
	regular posting to {news:news.announce.newusers}].

	(1999-12-17)

<messaging> One of {Usenet}'s huge collection of topic groups
	or {fora}.  {Usenet} groups can be "unmoderated" (anyone can
	post) or "moderated" (submissions are automatically directed
	to a {moderator}, who edits or filters and then posts the
	results).  Some newsgroups have parallel {mailing lists} for
	{Internet} people with no netnews access, with postings to the
	group automatically propagated to the list and vice versa.
	Some moderated groups (especially those which are actually
	gatewayed {Internet} {mailing lists}) are distributed as
	"{digests}", with groups of postings periodically collected
	into a single large posting with an index.

	Among the best-known are comp.lang.c (the {C}-language forum),
	comp.arch (on computer architectures), comp.Unix.wizards (for
	{Unix wizards}), rec.arts.sf-lovers (for science-fiction
	fans), and talk.politics.misc (miscellaneous political
	discussions and {flamage}).

	Barry Shein <bzs@world.std.com> is alleged to have said,
	"Remember the good old days when you could read all the group
	names in one day?"  This gives a good idea of the growth and
	size of {Usenet}.

	See also {netiquette}.

	[{Jargon File}]

	(1994-12-13)

<networking> {ATM}'s term for a {packet}.

	(1996-08-21)