<operating system> See {Microsoft Windows}, {Windows NT}.

	(1997-11-23)

<database, programming> (JDBC) Part of the {Java Development
	Kit} which defines an {application programming interface} for
	{Java} for standard {SQL} access to {databases} from Java
	{programs}.

	{Home
	(http://java.sun.com/products/jdk/1.1/docs/guide/jdbc/index.html)}.

	{FAQ (http://www.yoyoweb.com/Javanese/JDBC/FAQ.html)}.

	See also {Open Database Connectivity}.

	(1997-09-04)

1. A program which provides some service to other ({client})
	programs.  The connection between client and server is
	normally by means of {message passing}, often over a
	{network}, and uses some {protocol} to encode the client's
	requests and the server's responses.  The server may run
	continuously (as a {daemon}), waiting for requests to arrive
	or it may be invoked by some higher level daemon which
	controls a number of specific servers ({inetd} on {Unix}).

	There are many servers associated with the {Internet}, such as
	those for {HTTP}, {Network File System}, {Network Information
	Service} (NIS), {Domain Name System} (DNS), {FTP}, {news},
	{finger}, {Network Time Protocol}.  On Unix, a long list can
	be found in /etc/services or in the {NIS} database "services".
	See {client-server}.

	2. A computer which provides some service for other computers
	connected to it via a network.  The most common example is a
	{file server} which has a local disk and services requests
	from remote clients to read and write files on that disk,
	often using {Sun}'s {Network File System} (NFS) {protocol} or
	{Novell Netware} on {PCs}.  Another common example is a {web
	server}.

	[{Jargon File}]

	(2003-12-29)

<World-Wide Web, project> A {open source} {HTTP} server for
	{Unix}, {Windows NT}, and other {platforms}.  Apache was
	developed in early 1995, based on code and ideas found in the
	most popular HTTP server of the time, {NCSA httpd} 1.3.  It
	has since evolved to rival (and probably surpass) almost any
	other {Unix} based HTTP server in terms of functionality, and
	speed.  Since April 1996 Apache has been the most popular HTTP
	server on the {Internet}, in May 1999 it was running on 57% of
	all web servers.

	It features highly configurable error messages, {DBM}-based
	{authentication} {databases}, and {content negotiation}.

	Latest version: 1.3.9, as of 1999-10-27.

	{Home (http://www.apache.org/httpd.html)}.

	{FAQ (http://www.apache.org/docs/misc/FAQ.html)}.

	(1999-10-27)

1. <World-Wide Web> {Internet Information Server}.

	2. <language> {Idealized Instruction Set}.

	(1999-08-26)

1. The art of debugging a blank sheet of paper (or, in these
	days of on-line editing, the art of debugging an empty file).

	2. A pastime similar to banging one's head against a wall, but
	with fewer opportunities for reward.

	3. The most fun you can have with your clothes on (although
	clothes are not mandatory).

	[{Jargon File}]

	(2003-02-12)

In {object-oriented programming} sending a message to an
	{object} (to invoke a {method}) is equivalent to calling a
	{procedure} in traditional programming languages, except that
	the actual code executed may only be selected at run time
	depending on the {class} of the object.  Thus, in response to
	the message "drawSelf", the method code invoked would be
	different if the target object were a circle or a square.

	(1995-02-16)

Common term for "computer", usually when considered at the
	hardware level.  The {Turing Machine}, an early example of
	this usage, was however neither hardware nor software, but
	only an idea.

	[Earlier use?]

	(1995-02-15)

<World-Wide Web> (Or "website") Any computer on the
	{Internet} running a {World-Wide Web} {server} process.  A
	particular website is usually identified by the {hostname}
	part of a {URL}.  Multiple hostnames may actually map to the
	same computer in which case they are known as "{virtual
	servers}".

	(2005-07-12)

<operating system> ("Linus Unix") /li'nuks/ (but see below)
	An implementation of the {Unix} {kernel} originally written
	from scratch with no proprietary code.

	The kernel runs on {Intel} and {Alpha} hardware in the general
	release, with {SPARC}, {PowerPC}, {MIPS}, {ARM}, {Amiga},
	{Atari}, and {SGI} in active development.  The SPARC, PowerPC,
	ARM, {PowerMAC} - {OSF}, and 68k ports all support {shells},
	{X} and {networking}.  The Intel and SPARC versions have
	reliable {symmetric multiprocessing}.

	Work on the kernel is coordinated by Linus Torvalds, who holds
	the copyright on a large part of it.  The rest of the
	copyright is held by a large number of other contributors (or
	their employers).  Regardless of the copyright ownerships, the
	kernel as a whole is available under the {GNU} {General Public
	License}.  The GNU project supports Linux as its kernel until
	the research {Hurd} kernel is completed.

	This kernel would be no use without {application programs}.
	The GNU project has provided large numbers of quality tools,
	and together with other {public domain} software it is a rich
	Unix environment.  A compilation of the Linux kernel and these
	tools is known as a Linux distribution.  Compatibility modules
	and/or {emulators} exist for dozens of other computing
	environments.

	The kernel version numbers are significant: the odd numbered
	series (e.g. 1.3.xx) is the development (or beta) kernel which
	evolves very quickly.  Stable (or release) kernels have even
	major version numbers (e.g. 1.2.xx).

	There is a lot of commercial support for and use of Linux,
	both by hardware companies such as {Digital}, {IBM}, and
	{Apple} and numerous smaller network and integration
	specialists.  There are many commercially supported
	distributions which are generally entirely under the GPL.  At
	least one distribution vendor guarantees {Posix} compliance.
	Linux is particularly popular for {Internet Service
	Providers}, and there are ports to both parallel
	supercomputers and {embedded} {microcontrollers}.  {Debian} is
	one popular {open source} distribution.

	The pronunciation of "Linux" has been a matter of much debate.
	Many, including Torvalds, insist on the short I pronunciation
	/li'nuks/ because "Linus" has an /ee/ sound in Swedish
	(Linus's family is part of Finland's 6% ethnic-Swedish
	minority) and Linus considers English short /i/ to be closer
	to /ee/ than English long /i:/ dipthong.  This is consistent
	with the short I in words like "linen".  This doesn't stop
	others demanding a long I /li:'nuks/ following the english
	pronunciation of "Linus" and "minus".  Others say /li'niks/
	following {Minix}, which Torvalds was working on before Linux.

	{More on pronunciation
	(http://www.foldoc.org/pub/linux-pronunciation)}.

	{LinuxHQ (http://www.linuxhq.com/)}.  {slashdot
	(http://slashdot.org/)}.  {freshmeat (http://freshmeat.net/)}.
	{Woven Goods (http://www.fokus.gmd.de/linux/)}.  {Linux
	Gazette (http://www.ssc.com/lg)}.

	{funet Linux Archive (ftp://ftp.funet.fi/pub/Linux)}, {US
	mirror (ftp://sunsite.unc.edu/pub/Linux/)}, {UK Mirror
	(ftp://sunsite.doc.ic.ac.uk/packages/Linux/)}.

	(2000-06-09)

<unit> (b) {binary} digit.

	The unit of information; the amount of information obtained by
	asking a yes-or-no question; a computational quantity that can
	take on one of two values, such as false and true or 0 and 1;
	the smallest unit of storage - sufficient to hold one bit.

	A bit is said to be "set" if its value is true or 1, and
	"reset" or "clear" if its value is false or 0.  One speaks of
	setting and clearing bits.  To {toggle} or "invert" a bit is
	to change it, either from 0 to 1 or from 1 to 0.

	The term "bit" first appeared in print in the computer-science
	sense in 1949, and seems to have been coined by the eminent
	statistician, {John Tukey}.  Tukey records that it evolved
	over a lunch table as a handier alternative to "bigit" or
	"binit".

	See also {flag}, {trit}, {mode bit}, {byte}, {word}.

	[{Jargon File}]

	(2002-01-22)

<character> (Or "ctrl", "^") One (or a pair) of {modifier
	keys} found on all modern {keyboards}.  If the control key is
	held down while pressing and releasing certain other keys then
	a "{control character}" is generated, e.g. holding control and
	hitting "A" generates control-A ({ASCII} code 1).  The ASCII
	code for the control character is generally 64 less than that
	for the unmodified character.

	The control key does not generate any character on its own but
	most modern keyboards and {operating systems} allow a program
	to tell whether each of the individual keys on the keyboard
	(including modifier keys) is pressed at any time.

	Control characters mostly have some kind of "non-printing"
	effect on the output such as ringing the bell (Control-G) or
	advancing to the next line (Control-J).  Most have alternative
	names suggesting these functions (Bell, Line Feed, etc.).

	See {ASCII character table}.

	(1997-07-10)

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. <mathematics> In the theory of functions, the set of
	argument values for which a {function} is defined.

	See {domain theory}.

	2. <networking> A group of computers whose {hostnames} share a
	common suffix, the "domain name".  The last component of this
	is the {top-level domain}.

	See {administrative domain}, {Domain Name System}, {fully
	qualified domain name}.

	3. {Distributed Operating Multi Access Interactive Network}.

	4. <programming> A specific phase of the {software life cycle}
	in which a developer works.  Domains define developers' and
	users' areas of responsibility and the scope of possible
	relationships between products.

	5. The subject or market in which a piece of software is
	designed to work.

	(1997-12-26)

1. <networking> A computer connected to a {network}.

	The term {node} includes devices such as routers and printers
	which would not normally be called "hosts".

	2. <communications> A computer to which one connects using a
	{terminal emulator}.

	(1995-02-16)

<World-Wide Web> (By analogy with "{applet}") A {Java} program
	that runs as part of a {network} service, typically an {HTTP
	server} and responds to requests from {clients}.

	The most common use for a servlet is to extend a {web server}
	by generating {web content} dynamically.  For example, a
	{client} may need {information} from a {database}; a servlet
	can be written that receives the request, gets and processes
	the data as needed by the {client} and then returns the result
	to the {client}.

	{Applets} are also written in {Java} but run inside the {JVM}
	of a {HTML} {browser} on the {client}.  Servlets and applets
	allow the server and client to be extended in a modular way by
	dynamically loading code which communicates with the main
	program via a standard programming interface.

	Servlets are more flexible than {CGI scripts} and, being
	written in {Java}, more portable.

	The spelling "servelet" is occasionally seen but {JavaSoft}
	spell it "servlet".  There is no such thing as a "serverlet".

	{(http://java.sun.com/products/servlet/)}.

	(2002-10-06)

1. A new or better version of some {hardware} or {software}.

	Often used in {marketroid}-speak to mean "{bug fix}".

	2. The act of developing or installing a new version.

	(1995-03-14)