<mathematics, data> (Or "child", "successor") In a {tree}, a
	{node} pointed to by a {parent}, i.e. another node closer to
	the {root node}.

	(1998-11-14)

<chat> (Or "chat room", "room", depending on the system in
	question) The basic unit of group discussion in {chat} systems
	like {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 typing in summaries of 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).

	[{Jargon File}]

	(1998-01-25)

<networking> The {Berkeley Unix} mechansim for creating a
	virtual connection between processes.  Sockets interface
	{Unix}'s {standard I/O} with its {network} communication
	facilities.  They can be of two types, stream (bi-directional)
	or {datagram} (fixed length destination-addressed messages).
	The socket library function socket() creates a communications
	end-point or socket and returns a {file descriptor} with which
	to access that socket.  The socket has associated with it a
	socket address, consisting of a {port} number and the local
	host's network address.

	{Unix manual page}: socket(2).

	(1995-01-31)

That which surrounds, and gives meaning to, something else.

	<grammar> In a {grammar} it refers to the symbols before and
	after the symbol under consideration.  If the syntax of a
	symbol is independent of its context, the grammar is said to
	be {context-free}.

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)

1. <networking> A logical channel or channel endpoint in a
	communications system.  The {Transmission Control Protocol}
	and {User Datagram Protocol} {transport layer} protocols used
	on {Ethernet} use port numbers to distinguish between
	(demultiplex) different logical channels on the same {network
	interface} on a computer.

	Each {application program} has a unique port number associated
	with it, defined in /etc/services or the {Network Information
	Service} "services" database.  Some {protocols}, e.g. {telnet}
	and {HTTP} (which is actually a special form of telnet) have
	default ports specified as above but can use other ports as
	well.

	Some port numbers are defined in {RFC 3232} (which replaces
	RFC 1700).  Ports are now divided into: "Well Known" or
	"Privileged", and "Ephemeral" or "Unprivileged" (comprising
	"Registered", "Dynamic", "Private").

	(2004-12-30)

	2. <operating system, programming> To translate or modify
	{software} to run on a different {platform}, or the results of
	doing so.  The {portability} of the software determines how
	easy it is to port.

	3. <language> An {imperative} language descended from {Zed}
	from {Waterloo Microsystems} (now {Hayes} Canada) ca. 1979.

	["Port Language" document in the Waterloo Port Development
	System].

	(2002-06-19)

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)

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)