<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)

1. <language, programming> {programming language}.

	2. <human language> {natural language}.

	(1998-09-07)

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

	See also {dry run}.

	(1996-05-13)

<chat> as far as I know.

1. One of a small number of high-speed memory locations in a
	computer's {CPU}.  Registers differ from ordinary
	{random access memory} in several respects:

	There are only a small number of registers (the "register
	set"), typically 32 in a modern processor though some,
	e.g. {SPARC}, have as many as 144.  A register may be directly
	addressed with a few bits.  In contrast, there are usually
	millions of words of main memory (RAM), requiring at least
	twenty bits to specify a memory location.  Main memory
	locations are often specified indirectly, using an {indirect
	addressing} mode where the actual memory address is held in a
	register.

	Registers are fast; typically, two registers can be read and a
	third written -- all in a single cycle.  Memory is slower; a
	single access can require several cycles.

	The limited size and high speed of the register set makes it
	one of the critical resources in most computer architectures.
	{Register allocation}, typically one phase of the {back-end},
	controls the use of registers by a compiled program.

	See also {accumulator}, {FUBAR}, {orthogonal}, {register
	dancing}, {register allocation}, {register spilling}.

	2. An addressable location in a {memory-mapped} peripheral
	device.  E.g. the transmit data register in a {UART}.

<programming> (See below for synonyms) A data structure for
	storing items which are to be accessed in last-in first-out
	order.

	The operations on a stack are to create a new stack, to "push"
	a new item onto the top of a stack and to "pop" the top item
	off.  Error conditions are raised by attempts to pop an empty
	stack or to push an item onto a stack which has no room for
	further items (because of its implementation).

	Most processors include support for stacks in their
	{instruction set architectures}.  Perhaps the most common use
	of stacks is to store {subroutine} arguments and return
	addresses.  This is usually supported at the {machine code}
	level either directly by "jump to subroutine" and "return from
	subroutine" instructions or by {auto-increment} and
	auto-decrement {addressing modes}, or both.  These allow a
	contiguous area of memory to be set aside for use as a stack
	and use either a special-purpose {register} or a general
	purpose register, chosen by the user, as a {stack pointer}.

	The use of a stack allows subroutines to be {recursive} since
	each call can have its own calling context, represented by a
	stack frame or {activation record}.  There are many other
	uses.  The programming language {Forth} uses a data stack in
	place of variables when possible.

	Although a stack may be considered an {object} by users,
	implementations of the object and its access details differ.
	For example, a stack may be either ascending (top of stack is
	at highest address) or descending.  It may also be "full" (the
	stack pointer points at the top of stack) or "empty" (the
	stack pointer points just past the top of stack, where the
	next element would be pushed).  The full/empty terminology is
	used in the {Acorn Risc Machine} and possibly elsewhere.

	In a list-based or {functional language}, a stack might be
	implemented as a {linked list} where a new stack is an empty
	list, push adds a new element to the head of the list and pop
	splits the list into its head (the popped element) and tail
	(the stack in its modified form).

	At {MIT}, {pdl} used to be a more common synonym for stack,
	and this may still be true.  {Knuth} ("The Art of Computer
	Programming", second edition, vol. 1, p. 236) says:

	  Many people who realised the importance of stacks and queues
	  independently have given other names to these structures:
	  stacks have been called push-down lists, reversion storages,
	  cellars, dumps, nesting stores, piles, last-in first-out
	  ("LIFO") lists, and even yo-yo lists!

	[{Jargon File}]

	(1995-04-10)

1. <storage> To move the head of a {disk drive} radially,
	i.e., to move from one {track} to another.

	2. <storage> To wind the {tape} to a given location.

	3. <programming> To move the pointer that marks the next {byte}
	to be read from or written to a {file}.

	(1997-07-15)

1. <networking> {Packed Encoding Rules}.

	2. <mathematics> {partial equivalence relation}.

	(1998-05-27)

(VLIW) Used to describe an {assembly language} {instruction
	set} implemented using {horizontal microcode}.  A horizontally
	encoded instruction word which encodes four or more operations
	might be considered "very long".

	VLIW architectures are sometimes classified as a type of
	static {superscalar} architecture.  They are static in the
	sense that which units operate in parallel is determined by
	the instruction rather than by dynamic scheduling at run time.

	Producing code for VLIW machines is difficult; {trace
	scheduling} is a helpful compiler technique.

	The most famous VLIW machine was built by (the late)
	{Multiflow Computer, Inc.}

	(1994-11-11)

1. {Symbol Manipulation Program}.

	2. <computer, parallel> {symmetric multiprocessing}.

	(1995-03-19)

1. <language> An interactive extensible language using
	{postfix syntax} and a data stack, developed by Charles
	H. Moore in the 1960s.  FORTH is highly user-configurable and
	there are many different implementations, the following
	description is of a typical default configuration.

	Forth programs are structured as lists of "words" - FORTH's
	term which encompasses language keywords, primitives and
	user-defined {subroutines}.  Forth takes the idea of
	subroutines to an extreme - nearly everything is a subroutine.
	A word is any string of characters except the separator which
	defaults to space.  Numbers are treated specially.  Words are
	read one at a time from the input stream and either executed
	immediately ("interpretive execution") or compiled as part of
	the definition of a new word.

	The sequential nature of list execution and the implicit use
	of the data stack (numbers appearing in the lists are pushed
	to the stack as they are encountered) imply postfix syntax.
	Although postfix notation is initially difficult, experienced
	users find it simple and efficient.

	Words appearing in executable lists may be "{primitives}"
	(simple {assembly language} operations), names of previously
	compiled procedures or other special words.  A procedure
	definition is introduced by ":" and ended with ";" and is
	compiled as it is read.

	Most Forth dialects include the source language structures
	BEGIN-AGAIN, BEGIN-WHILE-REPEAT, BEGIN-UNTIL, DO-LOOP, and
	IF-ELSE-THEN, and others can be added by the user.  These are
	"compiling structures" which may only occur in a procedure
	definition.

	FORTH can include in-line {assembly language} between "CODE"
	and "ENDCODE" or similar constructs.  Forth primitives are
	written entirely in {assembly language}, secondaries contain a
	mixture.  In fact code in-lining is the basis of compilation
	in some implementations.

	Once assembled, primitives are used exactly like other words.
	A significant difference in behaviour can arise, however, from
	the fact that primitives end with a jump to "NEXT", the entry
	point of some code called the sequencer, whereas
	non-primitives end with the address of the "EXIT" primitive.
	The EXIT code includes the scheduler in some {multi-tasking}
	systems so a process can be {deschedule}d after executing a
	non-primitive, but not after a primitive.

	Forth implementations differ widely.  Implementation
	techniques include {threaded code}, dedicated Forth
	processors, {macros} at various levels, or interpreters
	written in another language such as {C}.  Some implementations
	provide {real-time} response, user-defined data structures,
	{multitasking}, {floating-point} arithmetic, and/or {virtual
	memory}.

	Some Forth systems support virtual memory without specific
	hardware support like {MMUs}.  However, Forth virtual memory
	is usually only a sort of extended data space and does not
	usually support executable code.

	FORTH does not distinguish between {operating system} calls
	and the language.  Commands relating to I/O, {file systems}
	and {virtual memory} are part of the same language as the
	words for arithmetic, memory access, loops, IF statements, and
	the user's application.

	Many Forth systems provide user-declared "vocabularies" which
	allow the same word to have different meanings in different
	contexts.  Within one vocabulary, re-defining a word causes
	the previous definition to be hidden from the interpreter (and
	therefore the compiler), but not from previous definitions.

	FORTH was first used to guide the telescope at NRAO, Kitt
	Peak.  Moore considered it to be a {fourth-generation
	language} but his {operating system} wouldn't let him use six
	letters in a program name, so FOURTH became FORTH.

	Versions include fig-FORTH, FORTH 79 and FORTH 83.

	{FAQs
	(http://www.complang.tuwien.ac.at/forth/faq/faq-general-2.html)}.
	{ANS Forth standard, dpANS6
	(http://www.taygeta.com/forth/dpans.html)}.

	FORTH Interest Group, Box 1105, San Carlos CA 94070.

	See also {51forth}, {F68K}, {cforth}, {E-Forth}, {FORML},
	{TILE Forth}.

	[Leo Brodie, "Starting Forth"].

	[Leo Brodie, "Thinking Forth"].

	[Jack Woehr, "Forth, the New Model"].

	[R.G. Loeliger, "Threaded Interpretive Languages"].

	2. {FOundation for Research and Technology - Hellas}.

	(1997-04-16)

<World-Wide Web> A {Java} program which can be distributed as
	an attachment in a {World-Wide Web} document and executed by a
	Java-enabled {web browser} such as Sun's {HotJava},
	{Netscape Navigator} version 2.0, or {Internet Explorer}.

	Navigator severely restricts the applet's file system and
	network access in order to prevent accidental or deliberate
	security violations.  Full Java applications, which run
	outside of the browser, do not have these restrictions.

	Web browsers can also be extended with {plug-ins} though these
	differ from applets in that they usually require manual
	installation and are {platform}-specific.  Various other
	languages can now be embedded within {HTML} documents, the
	most common being {JavaScript}.

	Despite Java's aim to be a "write once, run anywhere"
	language, the difficulty of accomodating the variety of
	browsers in use on the Internet has led many to abandon
	client-side processing in favour of {server}-side Java
	programs for which the term {servlet} was coined.

	Merriam Webster "Collegiate Edition" gives a 1990 definition:
	a short application program especially for performing a simple
	specific task.

	(2002-07-12)

1. Executable code, especially a "pure code" portion shared
	between multiple instances of a program running in a
	{multitasking} {operating system}.

	Compare {English}.

	2. Textual material in the mainstream sense; data in ordinary
	{ASCII} or {EBCDIC} representation (see {flat ASCII}).  "Those
	are text files; you can review them using the editor."

	These two contradictory senses confuse hackers too.

	[{Jargon File}]

	(1995-03-16)

<language> (Formula Translation) The first and, for a long
	time, the most widely used programming language for numerical
	and scientific applications.  The original versions lacked
	{recursive} procedures and {block structure} and had a
	line-oriented {syntax} in which certain columns had special
	significance.

	There have been a great many versions.

	The name is often written "FORTRAN", harking back to the days
	before computers were taught about lower case, but {ANSI}
	decreed, in about 1985 via the ANSI {FORTRAN} Technical
	Committee {TC}, that it should be "Fortran".

	See also: {Fortrash}.

	[Was {Fortran I} the first version?]

	(2000-07-07)

<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)

<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)