<programming, operating system> (Or "application", "app") A
	complete, self-contained program that performs a specific
	function directly for the user.  This is in contrast to system
	software such as the {operating system} {kernel}, {server}
	processes and libraries which exists to support application
	programs.

	Editors for various kinds of documents, {spreadsheets}, and
	text formatters are common examples of applications.  Network
	applications include clients such as those for {FTP},
	{electronic mail}, {telnet} and {WWW}.

	The term is used fairly loosely, for instance, some might say
	that a client and server together form a distributed
	application, others might argue that editors and compilers
	were not applications but tools for building applications.

	One distinction between an application program and the
	operating system is that applications always run in "user
	mode" (or "non-privileged mode"), while operating systems and
	related utilities may run in "supervisor mode" (or "privileged
	mode").

	The term may also be used to distinguish programs which
	communicate via a {graphical user interface} from those which
	are executed from the {command line}.

	(1994-11-28)

<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)

<language> One of the most used {object-oriented} languages, a
	superset of {C} developed primarily by {Bjarne Stroustrup}
	<bs@alice.att.com> at {AT&T} {Bell Laboratories} in 1986.

	In C++ a {class} is a user-defined {type}, syntactically a
	{struct} with {member functions}.  {Constructors} and
	{destructors} are member functions called to create or destroy
	{instances}.  A {friend} is a nonmember function that is
	allowed to access the private portion of a class.  C++ allows
	{implicit type conversion}, {function inlining}, {overloading}
	of operators and function names, and {default function
	arguments}.  It has {streams} for I/O and {references}.

	C++ 2.0 (May 1989) introduced {multiple inheritance},
	{type-safe linkage}, pointers to members, and {abstract
	classes}.

	C++ 2.1 was introduced in ["Annotated C++ Reference Manual",
	B. Stroustrup et al, A-W 1990].

	{MS-DOS
	(ftp://grape.ecs.clarkson.edu/pub/msdos/djgpp/djgpp.zip)},
	{Unix ANSI C++
	(ftp://gnu.org/pub/gnu/g++-1.39.0.tar.Z)} - X3J16
	committee. (They're workin' on it).

	See also {cfront}, {LEDA}, {uC++}.

	{Usenet} newsgroup: {news:comp.lang.c++}.

	["The C++ Programming Language", Bjarne Stroustrup, A-W,
	1986].

	(1996-06-06)

<programming> Code which is combined with another piece of
	{code} to determine how that code is executed.  The wrapper
	acts as an interface between its caller and the wrapped code.
	This may be done for compatibility, e.g. if the wrapped code
	is in a different programming language or uses different
	calling conventions, or for security, e.g. to prevent the
	calling program from executing certain functions.  The
	implication is that the wrapped code can only be accessed via
	the wrapper.

	(1998-12-15)

<software> Instructions for a computer in some programming
	language, often {machine language}.  The word "code" is often
	used to distinguish instructions from {data} (e.g. "The code
	is marked 'read-only'") whereas "{software}" is used in
	contrast with "{hardware}" and may consist of more than just
	code.

	(2000-04-08)

<storage> These days, usually used synonymously with {Random
	Access Memory} or {Read-Only Memory}, but in the general sense
	it can be any device that can hold {data} in
	{machine-readable} format.

	(1996-05-25)

<programming> With a qualifier, one of a class of
	resource-management bugs that occur when resources are not
	freed properly after operations on them are finished, so they
	effectively disappear (leak out).  This leads to eventual
	exhaustion as new allocation requests come in.

	One might refer to, say, a "window handle leak" in a {window
	system}.

	See {memory leak}, {fd leak}.

	[{Jargon File}]

	(1995-04-18)

A debugging tool from Pure Software.

<unit> /bi:t/ (B) A component in the machine {data hierarchy}
	usually larger than a {bit} and smaller than a {word}; now
	most often eight bits and the smallest addressable unit of
	storage.  A byte typically holds one {character}.

	A byte may be 9 bits on 36-bit computers.  Some older
	architectures used "byte" for quantities of 6 or 7 bits, and
	the PDP-10 and IBM 7030 supported "bytes" that were actually
	{bit-fields} of 1 to 36 (or 64) bits!  These usages are now
	obsolete, and even 9-bit bytes have become rare in the general
	trend toward power-of-2 word sizes.

	The term was coined by Werner Buchholz in 1956 during the
	early design phase for the {IBM} {Stretch} computer.  It was a
	mutation of the word "bite" intended to avoid confusion with
	"bit".  In 1962 he described it as "a group of bits used to
	encode a character, or the number of bits transmitted in
	parallel to and from input-output units".  The move to an
	8-bit byte happened in late 1956, and this size was later
	adopted and promulgated as a standard by the {System/360}
	{operating system} (announced April 1964).

	James S. Jones <jsjones@graceland.edu> adds:

	I am sure I read in a mid-1970's brochure by IBM that outlined
	the history of computers that BYTE was an acronym that stood
	for "Bit asYnchronous Transmission E__?__" which related to
	width of the bus between the Stretch CPU and its CRT-memory
	(prior to Core).

	Terry Carr <bear@mich.com> says:

	In the early days IBM taught that a series of bits transferred
	together (like so many yoked oxen) formed a Binary Yoked
	Transfer Element (BYTE).

	[True origin?  First 8-bit byte architecture?]

	See also {nibble}, {octet}.

	[{Jargon File}]

	(2003-09-21)

<language, architecture> (JVM) A specification for software
	which interprets {Java} programs that have been compiled into
	{byte-codes}, and usually stored in a ".class" file.  The JVM
	{instruction set} is {stack}-oriented, with variable
	instruction length.  Unlike some other instruction sets, the
	JVM's supports {object-oriented} programming directly by
	including instructions for object {method} invocation (similar
	to {subroutine} call in other instruction sets).

	The JVM itself is written in {C} and so can be {ported} to run
	on most {platforms}.  It needs {thread} support and {I/O} (for
	{dynamic class loading}).  The Java byte-code is independent
	of the platform.

	There are also some hardware implementations of the JVM.

	{Specification
	(http://www.javasoft.com/docs/books/vmspec/html/VMSpecTOC.doc.html)}.

	{Sun's Java chip
	(http://news.com/News/Item/0,4,9328,00.html)}.

	[Documentation?  Versions?]

	(2000-01-03)

1. Not operating.  "The up escalator is down" is considered a
	humorous thing to say, and "The elevator is down" always
	means "The elevator isn't working" and never refers to what
	floor the elevator is on.  With respect to computers, this
	term has passed into the mainstream; the extension to other
	kinds of machine is still hackish.

	2. "go down" To stop functioning; usually said of the
	{system}.  The message from the {console} that every hacker
	hates to hear from the operator is "System going down in 5
	minutes".

	3. "take down", "bring down" To deactivate purposely, usually
	for repair work or {PM}.  "I'm taking the system down to work
	on that bug in the tape drive."  Occasionally one hears the
	word "down" by itself used as a verb in this sense.

	See {crash}; opposite: {up}.

	[{Jargon File}]

	(1994-12-07)

<language, tool> A {Unix} tool written in {Tcl} and a {script
	language} for automating the operation of {interactive}
	applications such as {telnet}, {FTP}, {passwd}, {fsck},
	{rlogin}, {tip}, etc..  Expect can feed input to other
	programs and perform {pattern matching} on their output.  It
	is also useful for testing these applications.  By adding
	{Tk}, you can also wrap interactive applications in {X11}
	{GUIs}.

	{Home (http://expect.nist.gov/)}.

	["expect: Scripts for Controlling Interactive Tasks", Don
	Libes, Comp Sys 4(2), U Cal Press Journals, Nov 1991].

	(1997-06-09)

<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)

1. To wait for an event that will never occur.  "The system is
	hanging because it can't read from the crashed drive".  See
	{wedged}, {hung}.

	2. To wait for some event to occur; to hang around until
	something happens.  "The program displays a menu and then
	hangs until you type a character."  Compare {block}.

	3. To attach a peripheral device, especially in the
	construction "hang off": "We're going to hang another tape
	drive off the file server."  Implies a device attached with
	cables, rather than something that is strictly inside the
	machine's chassis.

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. <programming> An area of memory used for {dynamic memory
	allocation} where blocks of memory are allocated and freed in
	an arbitrary order and the pattern of allocation and size of
	blocks is not known until {run time}.  Typically, a program
	has one heap which it may use for several different purposes.

	Heap is required by languages in which functions can return
	arbitrary data structures or functions with {free variables}
	(see {closure}).  In {C} functions {malloc} and {free} provide
	access to the heap.

	Contrast {stack}.  See also {dangling pointer}.

	2. <programming> A data structure with its elements partially
	ordered (sorted) such that finding either the minimum or the
	maximum (but not both) of the elements is computationally
	inexpensive (independent of the number of elements), while
	both adding a new item and finding each subsequent
	smallest/largest element can be done in O(log n) time, where n
	is the number of elements.

	Formally, a heap is a {binary tree} with a key in each {node},
	such that all the {leaves} of the tree are on two adjacent
	levels; all leaves on the lowest level occur to the left and
	all levels, except possibly the lowest, are filled; and the
	key in the {root} is at least as large as the keys in its
	children (if any), and the left and right subtrees (if they
	exist) are again heaps.

	Note that the last condition assumes that the goal is finding
	the minimum quickly.

	Heaps are often implemented as one-dimensional {arrays}.
	Still assuming that the goal is finding the minimum quickly
	the {invariant} is

	   heap[i] <= heap[2*i] and heap[i] <= heap[2*i+1] for all i,

	where heap[i] denotes the i-th element, heap[1] being the
	first.  Heaps can be used to implement {priority queues} or in
	{sort} algorithms.

	(1996-02-26)

1. The {supervisor} program or {operating system} on a
	computer.

	2. The entire computer system, including input/output devices,
	the {supervisor} program or {operating system} and possibly
	other {software}.

	3. Any large program.

	4. Any method or {algorithm}.

	[{Jargon File}]

(Scientific computation) Output from a computation that may
	not be significant but at least indicates that the program is
	running.  Numbers may be used to placate management, grant
	sponsors, etc.  "Making numbers" means running a program
	because output - any output, not necessarily meaningful output
	- is needed as a demonstration of progress.

	See {pretty pictures}, {math-out}, {social science number}.

	[{Jargon File}]

	(1995-01-13)

1. <file system> {hard link} or {symbolic link}.

	2. <hypertext> {hyperlink}.

	(1997-10-22)

<operating system> (GUI) The use of pictures rather than just
	words to represent the input and output of a program.  A
	program with a GUI runs under some {windowing system}
	(e.g. The {X Window System}, {MacOS}, {Microsoft Windows},
	{Acorn} {RISC OS}, {NEXTSTEP}).  The program displays certain
	{icons}, {buttons}, {dialogue boxes}, etc. in its {windows} on
	the screen and the user controls it mainly by moving a
	{pointer} on the screen (typically controlled by a {mouse})
	and selecting certain objects by pressing buttons on the mouse
	while the pointer is pointing at them.  This contrasts with a
	{command line interface} where communication is by exchange of
	strings of text.

	Windowing systems started with the first {real}-time graphic
	display systems for computers, namely the {SAGE} Project
	[Dates?] and {Ivan Sutherland}'s {Sketchpad} (1963).  {Douglas
	Engelbart}'s {Augmentation of Human Intellect} project at
	{SRI} in the 1960s developed the {On-Line System}, which
	incorporated a mouse-driven cursor and multiple windows.
	Several people from Engelbart's project went to Xerox PARC in
	the early 1970s, most importantly his senior engineer, {Bill
	English}.  The Xerox PARC team established the {WIMP} concept,
	which appeared commercially in the {Xerox 8010} (Star) system
	in 1981.

	Beginning in 1980(?), led by {Jef Raskin}, the {Macintosh}
	team at {Apple Computer} (which included former members of the
	Xerox PARC group) continued to develop such ideas in the first
	commercially successful product to use a GUI, the Apple
	Macintosh, released in January 1984.  In 2001 Apple introduced
	{Mac OS X}.

	{Microsoft} modeled the first version of {Windows}, released
	in 1985, on Mac OS.  Windows was a GUI for {MS-DOS} that had
	been shipped with {IBM PC} and compatible computers since
	1981.  Apple sued Microsoft over infringement of the
	look-and-feel of the MacOS.  The court case ran for many
	years.

	[Wikipedia].

	(2002-03-25)

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)

<programming> Attempting to determine the cause of the
	symptoms of malfunctions detected by testing or by frenzied
	user complaints.

	The term is said to have been coined by {Grace Hopper}, based
	on the term "{bug}".

	(1999-06-29)

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)

<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)

1. <company> {SAP AG} (Systems, Applications and Products in
	Data Processing).

	2. <protocol> {Service Advertising Protocol}.

	3. <networking> {Service Access Point}.

	4. <language> {Symbolic Assembler Program}.

	(1999-05-26)

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)