1. To prepare to read or write a file.  This usually involves
	checking whether the file already exists and that the user has
	the necessary authorisation to read or write it.  The result
	of a successful open is usually some kind of {capability}
	(e.g. a {Unix} {file descriptor}) - a token that the user
	passes back to the system in order to access the file without
	further checks and finally to close the file.

	2. Abbreviation for "open (or left) parenthesis" - used when
	necessary to eliminate oral ambiguity.  To read aloud the LISP
	form (DEFUN FOO (X) (PLUS X 1)) one might say: "Open defun
	foo, open eks close, open, plus eks one, close close."

	3. Non-proprietary.  An open {standard} is one which can be
	used without payment.

	[{Jargon File}]

	(1995-01-31)

<language, programming> (Or "source", or rarely "source
	language") The form in which a computer program is written by
	the programmer.  Source code is written in some formal
	programming language which can be compiled automatically into
	{object code} or {machine code} or executed by an
	{interpreter}.

	(1995-01-05)

See {tuple}.

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)

<networking, programming> Work performed (or offered) by a
	{server}.  This may mean simply serving simple requests for
	data to be sent or stored (as with {file servers}, {gopher} or
	{http} servers, {e-mail} servers, {finger} servers, {SQL}
	servers, etc.); or it may be more complex work, such as that
	of {irc} servers, print servers, {X Windows} servers, or
	process servers.

	E.g. "Access to the finger {service} is restricted to the
	local {subnet}, for security reasons".

	(1997-09-11)

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)

<programming> (Or "computer program", "program", "code") The
	instructions executed by a computer, as opposed to the
	physical device on which they run (the "{hardware}").

	The term was coined by the eminent statistician, {John Tukey}.

	Programs stored on {non-volatile storage} built from
	{integrated circuits} (e.g. {ROM} or {PROM}) are usually
	called {firmware}.

	Software can be split into two main types - {system software}
	and application software or {application programs}.  System
	software is any software required to support the production or
	execution of application programs but which is not specific to
	any particular application.  Examples of system software would
	include the {operating system}, {compilers}, editors and
	sorting programs.

	Examples of application programs would include an accounts
	package or a {CAD} program.  Other broad classes of
	application software include {real-time} software, {business
	software}, scientific and engineering software, {embedded
	software}, personal computer software and {artificial
	intelligence} software.

	Software includes both {source code} written by humans and
	executable {machine code} produced by {assemblers} or
	{compilers}.  It does not usually include the data processed
	by programs unless this is in a format such as {multimedia}
	which depends on the use of computers for its presentation.
	This distinction becomes unclear in cases such as {spread
	sheets} which can contain both instructions (formulae and
	{macros}) and data.  There are also various intermediate
	compiled or {semi-compiled}, forms of software such as
	{library} files and {byte-code}.

	Some claim that {documentation} (both paper and electronic) is
	also software.  Others go further and define software to be
	programs plus documentation though this does not correspond
	with common usage.

	The noun "program" describes a single, complete and
	more-or-less self-contained list of instructions, often stored
	in a single {file}, whereas "code" and "software" are
	uncountable nouns describing some number of instructions which
	may constitute one or more programs or part thereof.  Most
	programs, however, rely heavily on various kinds of {operating
	system} software for their execution.  The nounds "code" and
	"software" both refer to the same thing but "code" tends to
	suggest an interest in the implementation details whereas
	"software" is more of a user's term.

	(2002-07-21)

<hardware, communications> (Modulator/demodulator) An
	electronic device for converting between serial data
	(typically {EIA-232}) from a computer and an audio signal
	suitable for transmission over a telephone line connected to
	another modem.  In one scheme the audio signal is composed of
	silence (no data) or one of two frequencies representing zero
	and one.

	Modems are distinguished primarily by the maximum data rate
	they support.  Data rates can range from 75 bits per second up
	to 56000 and beyond.  Data from the user (i.e. flowing from
	the local terminal or computer via the modem to the telephone
	line) is sometimes at a lower rate than the other direction,
	on the assumption that the user cannot type more than a few
	characters per second.

	Various data {compression} and error correction {algorithms}
	are required to support the highest speeds.  Other optional
	features are {auto-dial} (auto-call) and {auto-answer} which
	allow the computer to initiate and accept calls without human
	intervention.  Most modern modems support a number of
	different {protocols}, and two modems, when first connected,
	will automatically negotiate to find a common protocol (this
	process may be audible through the modem or computer's
	loudspeakers).  Some modem protocols allow the two modems to
	renegotiate ("retrain") if the initial choice of data rate is
	too high and gives too many transmission errors.

	A modem may either be internal (connected to the computer's
	{bus}) or external ("stand-alone", connected to one of the
	computer's {serial ports}).  The actual speed of transmission
	in characters per second depends not just the modem-to-modem
	data rate, but also on the speed with which the processor can
	transfer data to and from the modem, the kind of compression
	used and whether the data is compressed by the processor or
	the modem, the amount of noise on the telephone line (which
	causes retransmissions), the serial character format
	(typically {8N1}: one {start bit}, eight data bits, no
	{parity}, one {stop bit}).

	See also {acoustic coupler}, {adaptive answering}, {baud
	barf}, {Bulletin Board System}, {Caller ID}, {SoftModem},
	{U.S. Robotics}, {UUCP}, {whalesong}.

	{Usenet} newsgroup: {news:comp.dcom.modems}.

	(2002-05-04)

<operating system, programming> The process of carrying out
	the {instructions} in a computer program by a computer.

	See also {dry run}.

	(1996-05-13)

<communications> Communication, often two-way, of spoken
	information, by means of electrical signals carried by wires
	or radio waves.  The term was used to indicate transmission of
	the voice, as distinguished from telegraphy (done in {Morse
	code} and usually called "{continuous wave}" or CW
	transmission), radio teletypewriter (RTTY) transmission (also
	called FSK for "{Frequency Shift Keying}", the modulation
	scheme used by such machines), and later, facimile.

	(1995-03-14)

<networking, company> (IAP) A company or other origanisation
	which provides access to the {Internet} to businesses and/or
	consumers.  An IAP purchases an Internet link from another
	company that has a direct link to the Internet and resells
	portions of that {bandwidth} to the general public.

	For example, an IAP may purchase a {T1} link (1.544Mb/s) and
	resell that bandwidth in chunks consisting of {ISDN} (64Kb/s,
	128Kb/s) and analog {modems} (14.4Kb/s, 28.8Kb/s).  The IAP's
	customer base is likely to include both businesses and
	individuals.  Individual customers usually connect to the IAP
	via a modem and telephone line to a (preferably local) {point
	of presence}.

	An IAP may also be an {Internet Service Provider}.

	(1996-06-25)

<programming, communications> (TAPI, or "Telephone Application
	Program Interface") A {Windows 95} {Application Program
	Interface} enabling hardware independent access to telephone
	based communication.  TAPI covers a rather wide area of
	services from initialising the equipment (e.g. a {modem}) and
	placing a call to {voice mail} or control of a remote
	computer.

	[Telephone or Telephony?]

	(1995-12-05)

<programming> (JNI) A {native} programming interface for
	{Java} that allows Java code running inside a {Java Virtual
	Machine} to interoperate with {applications} and {libraries}
	written in other programming languages such as {C}, {C++} and
	{assembly language}.

	(1997-12-07)

<programming> (API, or "application programming interface")
	The interface (calling conventions) by which an {application
	program} accesses {operating system} and other services.  An
	API is defined at {source code} level and provides a level of
	{abstraction} between the application and the {kernel} (or
	other privileged utilities) to ensure the {portability} of the
	code.

	An API can also provide an interface between a {high level
	language} and lower level utilities and services which were
	written without consideration for the {calling conventions}
	supported by compiled languages.  In this case, the API's main
	task may be the translation of parameter lists from one format
	to another and the interpretation of {call-by-value} and
	{call-by-reference} arguments in one or both directions.

	(1995-02-15)

<networking> ("commercial") The {top-level domain} typically
	for American companies, although it sees heavy use for
	international companies and {vanity domains} of all types,
	whether in the US or not.

	(1999-01-26)

<operating system> All activities involved in completing any
	project on a computer from start to finish.  A job may involve
	several {processes} and several {programs}.

	This term originates from a time when a user would manually
	submit a job as a deck of {punched cards} which would
	typically include {source code} interspersed with {job control
	language} instructions to guide phases of the job such as
	{compilation}, {linking}, {execution} and printing.

	(2005-03-16)

See also {complete graph}, {complete inference system},
	{complete lattice}, {complete metric space}, {complete partial
	ordering}, {complete theory}.

	[1. or 2. or both?]

	(1996-04-24)