<graphics> (pixel) The smallest resolvable rectangular area of
	an {image}, either on a screen or stored in memory.  Each
	pixel in a {monochrome} image has its own brightness, from 0
	for black to the maximum value (e.g. 255 for an eight-bit
	pixel) for white.  In a colour image, each pixel has its own
	brightness and colour, usually represented as a triple of red,
	green and blue intensities (see {RGB}).

	Compare {voxel}.

	(1998-05-08)

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)

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

	(1997-11-23)

<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)

1. <hardware> A generic term for a {display device} that shows
	text and/or images on a roughly flat rectangular surface.  The
	most common type is usually refered to as a "{monitor}" and is
	based on a {cathode-ray tube}, though {flat panel} displays
	have, since around 2000, become increasingly competitive in
	price and performance.

	(2005-07-28)

	2. A {screen multiplexer} utility which lets you run multiple
	{interactive} {terminal sessions} (and {curses} programs)
	through a single terminal connection (on one {virtual
	console}, one terminal, through one {modem} link, {telnet}
	session or {xterm}).

	Screen can detach processes from one terminal and attach them
	to another.  "Auto-detach" lets you continue working after
	being disconnected and reconnected.  It supports keyboard
	driven cut and paste from any text and/or curses application
	(like {Lynx}) to any other (like {xemacs}).

	Screen comes with many {Linux} distributions and is available
	(free) on many other {Unix} {platforms}.

	(2005-07-29)

1. <hardware> the maximum number of {pixels} that can be
	displayed on a {monitor}, expressed as (number of horizontal
	pixels) x (number of vertical pixels), i.e., 1024x768.  The
	ratio of horizontal to vertical resolution is usually 4:3, the
	same as that of conventional television sets.

	2. <logic> A mechanical method for proving statements of
	{first order logic}, introduced by J. A. Robinson in 1965.
	Resolution is applied to two {clauses} in a {sentence}.  It
	eliminates, by {unification}, a {literal} that occurs
	"positive" in one and "negative" in the other to produce a new
	clause, the {resolvent}.

	For example, given the sentence:

		(man(X) => mortal(X))  AND  man(socrates).

	The literal "man(X)" is "negative".  The literal
	"man(socrates)" could be considered to be on the right hand
	side of the degenerate implication

		True => man(socrates)

	and is therefore "positive".  The two literals can be unified
	by the binding X = socrates.

	The {truth table} for the implication function is

		A | B | A => B
		--+---+-------
		F | F |   T
		F | T |   T
		T | F |   F
		T | T |   T

	(The implication only fails if its premise is true but its
	conclusion is false).  From this we can see that

		A => B   ==   (NOT A) OR B

	Which is why the left hand side of the implication is said to
	be negative and the right positive.  The sentence above could
	thus be written

		((NOT man(socrates)) OR mortal(socrates))
		AND
		man(socrates)

	Distributing the AND over the OR gives

		((NOT man(socrates)) AND man(socrates))
		OR
		mortal(socrates) AND man(socrates)

	And since (NOT A) AND A == False, and False OR A == A we can
	simplify to just

		mortal(socrates) AND man(socrates)

	So we have proved the new literal, mortal(socrates).

	Resolution with {backtracking} is the basic control mechanism
	of {Prolog}.

	See also {modus ponens}, {SLD Resolution}.

	3. <networking> {address resolution}.

	(1996-02-09)

<job> The person who uses a computer application, as opposed
	to those who developed or support it.  The end-user may or may
	not know anything about computers, how they work, or what to
	do if something goes wrong.  End-users do not usually have
	administrative responsibilities or privileges.

	End users are certain to have a different set of assumptions
	than the developers who created the application.

	(1997-03-29)

1. <programming> A common name for the {integer} data type.
	In {C} for example, it means a (signed) integer of the
	computer's native {word length}.

	2. <networking> The {top-level domain} for international
	organisations.

	(1999-01-26)

<language> A language compatible with the language
	{Dylan}(TM).  Thomas is NOT {Dylan}(TM).

	The first public release of a translator to {Scheme} by Matt
	Birkholz, Jim Miller, and Ron Weiss, written at {Digital
	Equipment Corporation}'s {Cambridge Research Laboratory} runs
	(slowly) on {MIT}'s {CScheme}, DEC's {Scheme->C}, Marc
	Feeley's {Gambi}, {Macintosh}, {PC}, {Vax}, {MIPS}, {Alpha},
	{680x0}.

	{(ftp://gatekeeper.pa.dec.com/pub/DEC/Thomas)}.

	Mailing list: <info-thomas@crl.dec.com>.

	["Dylan(TM) an object-oriented dynamic language", {Apple
	Computer}, Eastern Research and Technology, April 1992].

	(1992-09-11)

A language proposed by Cii {Honeywell-Bull} to meet the DoD
	{Ironman} requirements which led to {Ada}.  This language won
	in 1979.

	["On the GREEN Language Submitted to the DoD", E.W. Dijkstra,
	SIGPLAN Notices 13(10):16-21 (Oct 1978)].

	(1994-12-02)

<testing> To ascertain or appraise by comparing to a
	{standard}; to apply a {metric}.

	(1996-12-27)

1. A {cathode-ray tube} and associated electronics connected
	to a computer's video output.  A monitor may be either
	{monochrome} (black and white) or colour ({RGB}).  Colour
	monitors may show either digital colour (each of the red,
	green and blue signals may be either on or off, giving eight
	possible colours: black, white, red, green, blue, cyan,
	magenta and yellow) or analog colour (red, green and blue
	signals are continuously variable allowing any combination to
	be displayed).  Digital monitors are sometimes known as {TTL}
	because the voltages on the red, green and blue inputs are
	compatible with TTL logic chips.

	See also {gamut}, {multisync}, {visual display unit}.

	2. A programming language construct which encapsulates
	variables, access procedures and initialisation code within an
	abstract data type.  The monitor's variable may only be
	accessed via its access procedures and only one process may be
	actively accessing the monitor at any one time.  The access
	procedures are {critical sections}.  A monitor may have a
	queue of processes which are waiting to access it.

	3. A hardware device that measures electrical events such as
	pulses or voltage levels in a digital computer.

	4. To oversee a program during execution.  For example, the
	monitor function in the {Unix} {C} library enables profiling
	of a certain range of code addresses.  A histogram is produced
	showing how often the {program counter} was found to be at
	each position and how often each profiled function was called.

	{Unix} {man} page: monitor(3).

	5. A control program within the {operating system} that
	manages the allocation of system resources to active
	programs.

	6. A program that measures software performance.

<hardware> (CRT) An electrical device for displaying images by
	exciting phosphor dots with a scanned electron beam.  CRTs are
	found in computer {VDUs} and {monitors}, televisions and
	oscilloscopes.  The first commercially practical CRT was
	perfected on 29 January 1901 by Allen B DuMont.

	A large glass envelope containing a negative electrode (the
	cathode) emits electrons (formerly called "cathode rays") when
	heated, as in a {vacuum tube}.  The electrons are accelerated
	across a large voltage gradient toward the flat surface of
	the tube (the screen) which is covered with phosphor.  When an
	electron strikes the phosphor, light is emitted.  The electron
	beam is deflected by electromagnetic coils around the outside
	of the tube so that it scans across the screen, usually in
	horizontal stripes.  This scan pattern is known as a {raster}.
	By controlling the current in the beam, the brightness at any
	particular point (roughly a "{pixel}") can be varied.

	Different phosphors have different "{persistence}" - the
	length of time for which they glow after being struck by
	electrons.  If the scanning is done fast enough, the eye sees
	a steady image, due to both the persistence of the phospor and
	of the eye itself.  CRTs also differ in their {dot pitch},
	which determines their spatial {resolution}, and in whether
	they use {interlace} or not.

	(1994-11-17)

<company> The biggest supplier of {operating systems} and
	other software for {IBM PC} compatibles.  Software products
	include {MS-DOS}, {Microsoft Windows}, {Windows NT},
	{Microsoft Access}, {LAN Manager}, {MS Client}, {SQL Server},
	{Open Data Base Connectivity} (ODBC), {MS Mail}, and {SNA
	Server} for Windows NT.

	Microsoft was founded as "Micro-soft" in 1975 by {Bill Gates}
	(now CEO) and his high school pal Paul Allen.  Their first
	product was a version of {BASIC} for the new {Altair} computer
	[which one?].  In 1980, {IBM} chose Microsoft to supply the
	{operating system} for the {IBM PC}.

	On the UK television program "The Net" in May 1994, {Bill
	Gates} said he was betting his company on the {information
	highway}".

	Quarterly sales $1293M, profits $362M (Aug 1994).

	{Home (http://www.microsoft.com/)}.
	{(ftp://ftp.microsoft.com/)}.

	{Interesting Info and Other Microsoft WWW Servers
	(http://www-drg.microsoft.com/devinfo.htm)}.

	{Microsoft Windows Developer Information
	(http://www-drg.microsoft.com/devinfo.htm)}.

	{Microsoft Research Group Information
	(http://www.research.microsoft.com)}.

	{Win_News
	(http://www.microsoft.com/chicago/ms-www/ms-intro.htm)}.
	maintained by the Personal Operating Systems Division to
	distribute information on {Microsoft Windows}, {MS-DOS} and
	{Windows 95}.

	(1998-11-06)

<character> {decimal point}.

	See also {dot file}, {dot notation}.

	(1995-03-14)

[{Usenet}] 1. To duplicate a portion (or whole) of another's
	message (typically with attribution to the source) in a reply
	or followup, for clarifying the context of one's response.
	See the discussion of inclusion styles under "Hacker Writing
	Style".

	2. [{C}] "#include <disclaimer.h>" has appeared in {sig
	blocks} to refer to a notional "standard {disclaimer} file".

	[{Jargon File}]

<data, data processing, jargon> /day't*/ (Or "raw data")
	Numbers, {characters}, {images}, or other method of recording,
	in a form which can be assessed by a human or (especially)
	input into a {computer}, stored and {processed} there, or
	transmitted on some {digital channel}.  Computers nearly
	always represent data in {binary}.

	Data on its own has no meaning, only when interpreted by some
	kind of {data processing system} does it take on meaning and
	become {information}.

	People or computers can find patterns in data to perceive
	information, and information can be used to enhance
	{knowledge}.  Since knowledge is prerequisite to wisdom, we
	always want more data and information.  But, as modern
	societies verge on {information overload}, we especially need
	better ways to find patterns.

	1234567.89 is data.

	"Your bank balance has jumped 8087% to $1234567.89" is
	information.

	"Nobody owes me that much money" is knowledge.

	"I'd better talk to the bank before I spend it, because of
	what has happened to other people" is wisdom.

	(1999-04-30)

Dots per inch.

	A measure of resolution for printers, scanners and displays.

	{Laser printers} typically reach 300 DPI, though 600 DPI is
	becoming more common.  Commercial typesetters are usually
	around 1200 DPI.

	(1995-01-05)

<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)

<programming> (Or "procedure") A sequence of {instructions}
	for performing a particular task.  Most programming languages,
	including most {machine languages}, allow the programmer to
	define subroutines.  This allows the subroutine code to be
	called from multiple places, even from within itself (in which
	case it is called {recursive}).  The programming language
	implementation takes care of returning control to (just after)
	the calling location, usually with the support of call and
	return instructions at {machine language} level.

	Most languages also allow {arguments} to be passed to the
	subroutine, and one, or occasionally more, {return values} to
	be passed back.

	A {function} is often very similar to a subroutine, the main
	difference being that it is called chiefly for its return
	value, rather than for any {side effects}.

	(1996-10-01)

1. <hardware> {monitor}.

	2. <language> A vector of pointers to {activation records}.
	The Nth element points to the activation record containing
	variables declared at {lexical depth} N.  This allows faster
	access to variables from outer {scopes} than the alternative
	of linked activation records (but most variable accesses are
	either local or global or occasionally to the immediately
	enclosing scope).  Displays were used in some {ALGOL}
	implementations.

	(1996-02-22)

<tool> /row'ting/ Using a kind of rotating cutting tool called
	a router, pronounced /row't*/.  In the USA a {router},
	pronounced /row't*/, is also a network device that performs
	"routing".  In the UK, the network device is pronounced
	/roo't*/ and what it does is spelled "{routeing}".

	(2002-07-31)

<architecture> {Data} transferred from a computer system to
	the outside world via some kind of {output device}.

	Opposite: {input}.

	(1997-04-28)

1. {function composition}.

	2. {typesetting}.

	(2000-08-16)

<graphics> To show a smaller area of an {image} at a higher
	magnification ("zoom in") or a larger area at a lower
	magnification ("zoom out"), as though using a zoom lense on a
	camera.

	Unlike in an optical system, zooming in on a computer {image}
	does not necessarily increase the amount of detail displayed
	since this is limited by what is actually stored in the image.
	Similarly, you cannot zoom out beyond the full size of the
	image.

	(1997-10-24)

1. {audio}.

	2. <logic> An {inference system} A is sound with respect to
	another system B if A can only reach conclusions which are
	true in B.  A {type inference} system is considered sound with
	respect to a {semantics} if the type inferred for an
	expression is the same as the type inferred for the meaning of
	that expression under the semantics.

	The dual to soundness is {complete}ness.

	(1995-03-01)

<standard> Standards are necessary for {interworking},
	{portability}, and {reusability}.  They may be {de facto
	standards} for various communities, or officially recognised
	national or international standards.

	{Andrew Tanenbaum}, in his Computer Networks book, once said,
	"The nice thing about standards is that there are so many of
	them to choose from", a reference to the fact that competing
	standards become a source of confusion, division,
	obsolescence, and duplication of effort instead of an
	enhancement to the usefulness of products.

	Some bodies concerned in one way or another with computing
	standards are {IAB} ({RFC} and {STD}), {ISO}, {ANSI}, {DoD},
	{ECMA}, {IEEE}, {IETF}, {OSF}, {W3C}.

	(1999-07-06)

<process> The approach that engineering (and some other)
	disciplines use to specify how to create or do something.  A
	successful design must satisfies a (perhaps informal)
	{functional specification} (do what it was designed to do);
	conforms to the limitations of the target medium (it is
	possible to implement); meets implicit or explicit
	requirements on performance and resource usage (it is
	efficient enough).

	A design may also have to satisfy restrictions on the design
	process itself, such as its length or cost, or the tools
	available for doing the design.

	In the {software life-cycle}, design follows {requirements
	analysis} and is followed by implementation.

	["Object-Oriented Analysis and Design with Applications", 2nd
	ed., Grady Booch].

	(1996-12-08)

<tool> A {spreadsheet} program from {Microsoft}, part of their
	{Microsoft Office} suite of productivity tools for {Microsoft
	Windows} and {Macintosh}.  Excel is probably the most widely
	used spreadsheet in the world.

	Current version: Excel 97, as of 1997-01-14.

	{Home (http://www.microsoft.com/msexcel/)}.

	[Feature summary?  History?]

	(1997-01-14)

<software> (Or "option", "flag", "switch", "option switch") An
	argument to a command that modifies its function rather than
	providing data.  Options generally start with "-" in {Unix} or
	"/" in {MS-DOS}.  This is usually followed by a single letter
	or occasionally a digit.

	Some commands require each option to be a separate argument,
	introduced by a new "-" or "/", others allow multiple option
	letters to be concatenated into a single argument with a
	single "-" or "/", e.g. "ls -al".  A few Unix commands
	(e.g. {ar}, {tar}) allow the "-" to be omitted.  Some options
	may or must be followed by a value, e.g. "cc prog.c -o prog",
	sometimes with and sometimes without an intervening space.

	{getopt} and {getopts} are commands for parsing command line
	options.  There is also a {C} library routine called getopt
	for the same purpose.

	(1996-12-11)