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)

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)

<file system> An elementary unit of allocation of a disk made
	up of one or more physical {blocks}.

	A {file} is made up of a whole number of possibly
	non-contiguous clusters.  The cluster size is a tradeoff
	between space efficiency (the bigger is the cluster, the
	bigger is on the average the wasted space at the end of each
	file) and the length of the {FAT}.

	(1996-11-04)

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

	See also {dry run}.

	(1996-05-13)

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

	(1997-11-23)

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)

<hardware> Part of a computer, typically a separate circuit
	board, which allows the computer to use certain kinds of
	{peripheral} devices.  A {disk controller} is used to connect
	{hard disks} and {floppy disks}, a {network controller} is
	used for {Ethernet}.  Other controllers are: {keyboard
	controller}, {interrupt controller} and {graphics controller}.

	(1998-03-16)

<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)

<programming> An individual {object} of a certain {class}.
	While a class is just the type definition, an actual usage of
	a class is called "instance".  Each instance of a class can
	have different values for its {instance variables}, i.e. its
	{state}.

	(1998-03-06)

1. <algorithm> {Depth-First Search}.

	2. <file system> {Distributed File System}.

<database, networking> Creating and maintaining a duplicate
	copy of a database or file system on a different computer,
	typically a {server}.  The term usually implies the
	intelligent copying of parts of the source database which have
	changed since the last replication with the destination.

	Replication may be one-way or two-way.  Two-way replication is
	much more complicated because of the possibility that a
	replicated object may have been updated differently in the two
	locations in which case some method is needed to reconcile the
	different versions.

	For example, {Lotus Notes} can automatically distribute
	document databases across telecommunications networks.  Notes
	supports a wide range of network {protocols} including {X25}
	and {Internet} {TCP/IP}.

	Compare {mirror}.  See also {rdist}.

	(1997-12-12)

1. <language> {Synthesizer Specification Language}.

	2. <language> {Syntax/Semantic Language} (S/SL).

	3. <networking, World-Wide Web> {Secure Sockets Layer}.

	(1996-09-08)

<programming> The multiple kilograms of macerated, pounded,
	steamed, bleached, and pressed trees that accompany most
	modern software or hardware products (see also {tree-killer}).
	Hackers seldom read paper documentation and (too) often resist
	writing it; they prefer theirs to be terse and {on-line}.  A
	common comment on this predilection is "You can't {grep} dead
	trees".

	See {drool-proof paper}, {verbiage}, {treeware}.

	[{Jargon File}]

	(2003-10-25)

<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)

<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)

<hardware> The physical, touchable, material parts of a
	computer or other system.  The term is used to distinguish
	these fixed parts of a system from the more changable
	{software} or {data} components which it executes, stores, or
	carries.

	Computer hardware typically consists chiefly of electronic
	devices ({CPU}, {memory}, {display}) with some
	electromechanical parts (keyboard, {printer}, {disk drives},
	{tape drives}, loudspeakers) for input, output, and storage,
	though completely non-electronic (mechanical,
	electromechanical, hydraulic, biological) computers have also
	been conceived of and built.

	See also {firmware}, {wetware}.

	(1997-01-23)

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

	2. <language> {Idealized Instruction Set}.

	(1999-08-26)

1. {Domain Name System}.

	2. Distributed Name Service.  See {DECdns}.

<jargon> /n[y]oo'bee/ (Originally from British public-school
	and military slang variant of "new boy") An inexperienced user
	of {Usenet} or other system.

	This term surfaced in the {newsgroup} {news:talk.bizarre} but
	is now in wide use.  Criteria for being considered a newbie
	vary wildly; a person can be called a newbie in one newsgroup
	while remaining a respected regular in another.  The label
	"newbie" is sometimes applied as a serious insult to a person
	who has been around {Usenet} for a long time but who carefully
	hides all evidence of having a clue.

	See {BIFF}.

	[{Jargon File}]

	(1998-02-18)

1. <operating system, software> The sequence of states of an
	executing {program}.  A process consists of the program {code}
	(which may be shared with other processes which are executing
	the same program), private data, and the state of the
	{processor}, particularly the values in its {registers}.  It
	may have other associated resources such as a {process
	identifier}, open files, {CPU time} limits, {shared memory},
	{child processes}, and {signal handlers}.

	One process may, on some {platforms}, consist of many
	{threads}.  A {multitasking} {operating system} can run
	multiple processes {concurrently} or in {parallel}, and allows
	a process to spawn "child" processes.

	(2001-06-16)

	2. <business> The sequence of activities, people, and systems
	involved in carrying out some business or achieving some
	desired result.  E.g. software development process, project
	management process, configuration management process.

	(2001-06-16)

1. <unit, text> (Sometimes abbreviated "pt") The unit of
	length used in {typography} to specify text character height,
	{rule} width, and other small measurements.

	There are six slightly different definitions: {Truchet point},
	{Didot point}, {ATA point}, {TeX point}, {Postscript point},
	and {IN point}.

	In Europe, the most commonly used is Didot and in the US, the
	formerly standard ATA point has essentially been replaced by
	the PostScript point due to the demise of traditional
	typesetting systems and rise of desktop computer based systems
	running software such as {QuarkXPress}, {Adobe InDesign} and
	{Adobe Pagemaker}.

	There are 20 {twips} in a point and 12 points in a {pica}
	(known as a "Cicero" in the Didot system).

	{Different point systems
	(http://www.vakcer.com/oberon/dtp/fonts/point.htm)}.

	(2004-12-23)

	2. <hardware> To move a {pointing device} so that the
	on-screen pointer is positioned over a certain object on the
	screen such as a {button} in a {graphical user interface}.  In
	most {window systems} it is then necessary to {click} a
	(physical) button on the pointing device to activate or select
	the object.  In some systems, just pointing to an object is
	known as "mouse-over" {event} which may cause some help text
	(called a "tool tip" in {Windows}) to be displayed.

	(2001-05-21)

1. <networking> {e-mail address}.

	2. <networking> {Internet address}.

	3. <networking> {MAC address}.

	4. <storage, programming> An unsigned integer used to select
	one fundamental element of storage, usually known as a {word}
	from a computer's {main memory} or other storage device.  The
	{CPU} outputs addresses on its {address bus} which may be
	connected to an {address decoder}, {cache controller}, {memory
	management unit}, and other devices.

	While from a hardware point of view an address is indeed an
	integer most {strongly typed} programming languages disallow
	mixing integers and addresses, and indeed addresses of
	different data types.  This is a fine example for {syntactic
	salt}: the compiler could work without it but makes writing
	bad programs more difficult.

	(1997-07-01)

1. To copy {data} (often {program} {code} to be {run}) into
	{memory}, possibly {parsing} it somehow in the process.
	E.g. "{WordPerfect} can't load this {RTF} file - are you sure
	it didn't get corrupted in the {download}?"  Opposite of
	{save}.

	2. The degree to which a computer, {network}, or other
	resource is used, sometimes expressed as a percentage of the
	maximum available.  E.g. "What kind of CPU load does that
	program give?", "The network's constantly running at 100%
	load".  Sometimes used, by extension, to mean "to increase the
	level of use of a resource".  E.g. "Loading a spreadsheet
	really loads the CPU".  See also: {load balancing}.

	3. To {install} a piece of {software} onto a system.
	E.g. "The computer guy is gonna come load Excel on my laptop
	for me".  This usage is widely considered to be incorrect.

	(2002-07-02)

<algorithm> A {scheduling} {algorithm} in which processes are
	activated in a fixed cyclic order.  Those which cannot proceed
	because they are waiting for some event (e.g. termination of a
	{child process} or an input/output operation) simply return
	control to the scheduler.  The virtue of round-robin
	scheduling is its simplicity - only the processes themselves
	need to know what they are waiting for or how to tell if it
	has happened.  However, if a process goes back to sleep just
	before the event for which it is waiting occurs then the event
	will not get handled until all the other processes have been
	activated.

	Compare {priority scheduling}.

	(1996-02-10)

<World-Wide Web, database, tool> {Allaire Corporation}'s
	commercial {database} application development tool that allows
	{databases} to have a {World-Wide Web} {interface}, so a
	database can be queried and updated using a {web browser}.

	The ColdFusion Server application runs on the {web server} and
	has access to a {database}.  ColdFusion files on the web
	server are {HTML} pages with additional ColdFusion commands to
	{query} or {update} the database, written in {CFML}.  When the
	page is requested by the user, the {web server} passes the
	page to the Cold Fusion application, which executes the {CFML}
	commands, places the results of the {CFML} commands in the
	{HTML} file, and returns the page to the {web server}.  The
	page returned to the {web server} is now an ordinary {HTML}
	file, and it is sent to the user.

	Examples of ColdFusion applications include order entry, event
	registration, catalogue search, directories, calendars, and
	interactive training.  ColdFusion applications are robust
	because all database interactions are encapsulated in a single
	industrial-strength {CGI} script.  The formatting and
	presentation can be modified and revised at any time (as
	opposed to having to edit and recompile {source code}).

	ColdFusion Server can connect with any database that supports
	{ODBC} or {OLE DB} or one that has a native database driver.
	Native database drivers are available for {Oracle} and
	{Sybase} databases.

	ColdFusion is available for {Windows}, {Solaris}, and {HP-UX}.
	A {development environment} for creating ColdFusion files,
	called ColdFusion Studio, is also available for {Windows}.

	Current version: MX(6), as of 2003-07-11.

	The {filename extension} for ColdFusion files is .cfm

	{Home (http://www.coldfusion.com/)}.

	(2003-07-27)

<networking> Hardware and software data communication systems.

	The {OSI} seven layer model attempts to provide a way of
	partitioning any computer network into independent modules
	from the lowest (physical) layer to the highest (application)
	layer.  Many different specifications exist at each of these
	layers.

	Networks are often also classified according to their
	geographical extent: {local area network} (LAN), {metropolitan
	area network} (MAN), {wide area network} (WAN) and also
	according to the {protocols} used.

	See {BITNET}, {Ethernet}, {Internet}, {Novell}, {PSTN},
	{network, the}.

	[Tanenbaum, A., "Computer Networks; 2nd ed.", Prentice Hall,
	Englewood Cliffs, NJ, 1989.]

	(1995-03-10)

<electronics> The quantity of {charge} per unit time, measured
	in Amperes (Amps, A).  By historical convention, the sign of
	current is positive for currents flowing from positive to
	negative {potential}, but experience indicates that electrons
	are negatively charged and flow in the opposite direction.

	(1995-10-05)

<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)

<mathematics> Every field of mathematics has a different
	meaning of dual.  Loosely, where there is some binary symmetry
	of a theory, the image of what you look at normally under this
	symmetry is referred to as the dual of your normal things.

	In linear algebra for example, for any {vector space} V, over
	a {field}, F, the vector space of {linear maps} from V to F is
	known as the dual of V.  It can be shown that if V is
	finite-dimensional, V and its dual are {isomorphic} (though no
	isomorphism between them is any more natural than any other).

	There is a natural {embedding} of any vector space in the dual
	of its dual:

	    V -> V'': v -> (V': w -> wv : F)

	(x' is normally written as x with a horizontal bar above it).
	I.e. v'' is the linear map, from V' to F, which maps any w to
	the scalar obtained by applying w to v.  In short, this
	double-dual mapping simply exchanges the roles of function and
	argument.

	It is conventional, when talking about vectors in V, to refer
	to the members of V' as covectors.

	(1997-03-16)

1. <programming, operating system> A simple item of data that
	identifies a resource.  For example, a {Unix} file handle
	identifies an open file and associated data such as whether it
	was opened for read or write and the current read/write
	position.  On the {Macintosh}, a handle is a pointer to a
	pointer to some dynamically-allocated memory.  The extra level
	of indirection allows on-the-fly {memory compaction} or
	{garbage collection} without invalidating application program
	references to the allocated memory.

	2. <jargon> An alias used intended to conceal a user's true
	identity in an electronic message.  The term is common on
	Citizen's Band and other amateur radio but, in that context
	usually means the user's real name as {FCC} rules forbid
	concealing one's identity.

	Use of grandiose handles is characteristic of {crackers},
	{weenies}, {spods}, and other lower forms of network life;
	true hackers travel on their own reputations.

	Compare {nick}.

	[{Jargon File}]

	(2004-07-20)

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)

The unit of data sent across a {network}.  "Packet" is a
	generic term used to describe a unit of data at any layer of
	the {OSI} {protocol stack}, but it is most correctly used to
	describe {application layer} data units ("{application
	protocol data unit}", APDU).

	See also {datagram}, {frame}.

	(1994-11-30)

<jargon> The opposite of {logical} in its jargon sense.
	Compare {real}, {virtual}, and {transparent}.

	It is said that what you can touch and see is real; what you
	can see but not touch is virtual; what you can touch but not
	see is transparent; and what you can neither touch nor see is
	probably imaginary.

	(2001-10-26)

<language, programming> (J2EE) {Sun}'s {Java} platform for
	{multi-tier} {server}-oriented {enterprise} {applications}.

	The basis of J2EE is {Enterprise JavaBeans} (EJB).

	See also the Standard edition {J2SE} and the Micro edition
	{J2ME}.

	{Home (http://java.sun.com/j2ee/)}.

	(2000-04-20)

1. <networking> {Packed Encoding Rules}.

	2. <mathematics> {partial equivalence relation}.

	(1998-05-27)

<programming> The name given in {Smalltalk} and other
	{object-oriented languages} to a procedure or routine
	associated with one or more {classes}.  An {object} of a
	certain class knows how to perform actions, e.g. printing
	itself or creating a new instance of itself, rather than the
	function (e.g. printing) knowing how to handle different types
	of object.

	Different classes may define methods with the same name
	(i.e. methods may be {polymorphic}).  The term "method" is used
	both for a named operation, e.g. "PRINT" and also for the code
	which a specific class provides to perform tha
	t operation.

	Most methods operate on objects that are instances of a
	certain class.  Some object-oriented languages call these
	"object methods" to distinguish then from "{class methods}".

	In {Smalltalk}, a method is defined by giving its name,
	documentation, temporary local variables and a sequence of
	expressions separated by "."s.

	(2000-03-22)

1. Non-functional; {down}; {crash}ed.  Especially used of
	{hardware}.

	2. At {XEROX PARC}, software that is working but not
	undergoing continued development and support.

	[{Jargon File}]

<programming> (Or "remark") Explanatory text embedded in
	program {source} (or less often data) intended to help human
	readers understand it.

	Code completely without comments is often hard to read, but
	too heavily commented code isn't much better, especially if
	the comments are not kept up-to-date with changes to the code.
	Too much commenting may mean that the code is
	over-complicated.  A good rule is to comment everything that
	needs it but write code that doesn't need much of it.

	A particularly irksome form of over-commenting explains
	exactly what each statement does, even when it is obvious to
	any reasonably competant programmer, e.g.

		/* Open the input file */
		infd = open(input_file, O_RDONLY);

	(1998-04-28)