Application Portability Architecture


<web, project>

A open source HTTP server for Unix, Windows NT, and other platforms. Apache was developed in early 1995, based on code and ideas found in the most popular HTTP server of the time, NCSA httpd 1.3. It has since evolved to rival (and probably surpass) almost any other Unix based HTTP server in terms of functionality, and speed. Since April 1996 Apache has been the most popular HTTP server on the Internet, in May 1999 it was running on 57% of all web servers.

It features highly configurable error messages, DBM-based authentication databases, and content negotiation.



Last updated: 1999-10-27

Apache Software Foundation

<open source, body>

(ASF) A consortium that manages the development of the Apache web server, dozens of XML- and Java-based projects (under the name Jakarta), the Ant build tool, the Geronimo J2EE server, the SpamAssassin anti-SPAM tool, and much more.

Apache Home.

Last updated: 2005-01-26


Array Processor Assembly Language


A PArse REquest Language

A PArse REquest Language


(APAREL) A PL/I extension to provide BNF parsing routines, for IBM 360.

["APAREL: A Parse Request Language", R.W. Balzer et al, CACM 12(11) (Nov 1969)].

Last updated: 1995-11-26


Association for Progressive Communications


Algorithmic Processor Description Language


<audio, compression>

A lossless audio compression algorithm from MonkeysAudio.

Last updated: 2001-12-20



A graphics package from the Ohio Supercomputer Centre.

Last updated: 1995-11-29


Application Program Interface


Advanced Programmable Interrupt Controller


A Programming Language



An APL extension from IBM with nested arrays.

["APL2 Programming: Language Reference", IBM, Aug 1984. Order No. SH20-9227-0].

Last updated: 1995-11-29



An APL variant with ALGOL-like control structure, from Hewlett-Packard(?).

Last updated: 1995-11-29


<text, tool>

A Web to APL and Web to TeX translator by Dr. Christoph von Basum of The University of Bielefeld, Germany.


Last updated: 1992-12-27


Advanced Power Management

Apollo Computer


A company making workstations often used for CAD.

From 1980 to 1987, Apollo were the largest manufacturer of network workstations. Apollo workstations ran Aegis, a proprietary operating system with a Posix-compliant Unix alternative frontend. Apollo's networking was particularly elegant, among the first to allow demand paging over the network, and allowing a degree of network transparency and low sysadmin-to-machine ratio that is still unmatched.

Apollo's largest customers were Mentor Graphics (electronic design), GM, Ford, Chrysler, and Boeing (mechanical design). Apollo was acquired by Hewlett-Packard in 1989, and gradually closed down over the period 1990-1997.

Last updated: 2003-07-18


single quote


application program


Advanced Program-to-Program Communications



A set of objects used by the application builder for the NEXTSTEP environment.

Last updated: 1995-03-13



A revision of APL for the Illiac IV.

Last updated: 1995-04-28


Apple Computer, Inc.

Apple Address Resolution Protocol


(AARP) Apple's system to allow AppleTalk protocol to work over networks other than LocalTalk, such as Ethernet or Token Ring. AppleTalk nodes announce their presence to the network so that other nodes can address messages to them. AARP maps between AppleTalk addresses and other schemes. It is actually a general address mapping protocol that can be used to map between addresses at any protocol level.

[G. Sidhu, R. Andrews, and A. Oppenheimer, "Inside AppleTalk", Addison Wesley, 1990].

Last updated: 2006-04-18

Apple Attachment Unit Interface

<hardware, networking>

(AAUI) A 14-position, 0.050-inch-spaced ribbon contact connector. Early Power Macs and Quadras had an AAUI (Apple Attachment Unit Interface) port (rectangular shaped) for Ethernet, which requires a transceiver. To use twisted pair cabling, you would need to get a twisted pair transceiver for the computer with an AAUI port. Some Power Mac computers had both an AAUI and RJ-45 port; you can use one or the other, but not both.

The pin-out is:

  Pin   Signal Name     Signal Description
  ----  --------------  ---------------------------------
  1     FN Pwr          Power (+12V @ 2.1W or +5V @ 1.9W)
  2     DI-A            Data In circuit A
  3     DI-B            Data In circuit B
  4     VCC             Voltage Common
  5     CI-A            Control In circuit A
  6     CI-B            Control In circuit B
  7     +5V             +5 volts (from host)
  8     +5V             Secondary +5 volts (from host)
  9     DO-A            Data Out circuit A
  10    DO-B            Data Out circuit B
  11    VCC             Secondary Voltage Common
  12    NC              Reserved
  13    NC              Reserved
  14    FN Pwr          Secondary +12V @ 2.1W or +5V @ 1.9W
  Shell Protective Gnd  Protective Ground

AAUI signals have the same description, function, and electrical requirements as the AUI signals of the same name, as detailed in IEEE 802.3-1990 CSMA/CD Standard, section 7.

Last updated: 2000-02-10

Apple Computer, Inc.


Manufacturers of the Macintosh range of personal computers as well as the earlier Apple I, Apple II and Lisa. Founded on 1 April 1976 by Steve Jobs and Steve Wozniak.

Apples were among the first microcomputers. They originally used the 6502 processor and are still being made (August 1994), now using the 65816. The Apple II line, which includes the Apple I, is the longest existing line of microcomputers.

Steve Jobs left Apple (involuntarily) and started NeXT and later returned when Apple bought NeXT in late 1997(?).

Quarterly sales $2150M, profits $138M (Aug 1994). http://apple.com/.

[Dates? More?]

Last updated: 1998-03-13

Apple II


An 8-bit personal computer with a 6502 processor, from Apple Computer. It was invented by Steve Wozniak and was very popular from about 1980 until the first several years of MS-DOS IBM PCs.

Last updated: 1995-01-12

Apple Macintosh


Apple Newton


A Personal Digital Assistant produced by Apple Computer. The Newton provides a clever, user-friendly interface and relies solely on pen-based input. Eagerly anticipated, the Newton uses handwriting recognition software to "learn" the users handwriting and provide reliable character recognition.

Various third-party software applications are available and add-on peripherals like wireless modems for Internet access are being sold by Apple Computer, Inc. and its licensees.

Newton Inc.'s NewtonOS competes with Microsoft Corporation's Windows CE, and was to be compatible with DEC's StrongARM SA-1100, an embedded 200MHz microprocessor, which was due in 1998.


Handwriting recognition example.

Last updated: 1997-09-12

Apple Open Collaboration Environment


(AOCE) Software for electronic mail and directory services.

Last updated: 1995-03-08



An object-oriented shell language for the Macintosh, approximately a superset of HyperTalk.

Last updated: 1995-12-10

Applesoft BASIC


A version of BASIC for Apple computers.

Last updated: 1995-12-10



A Java program which can be distributed as an attachment in a 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.

Last updated: 2002-07-12


<networking, protocol>

A proprietary local area network protocol developed by Apple Computer, Inc. for communication between Apple products (e.g. Macintosh) and other computers. This protocol is independent of the network layer on which it runs. Current implementations exist for Localtalk, a 235 kilobyte per second local area network and Ethertalk, a 10 megabyte per second local area network.

Last updated: 1995-03-08

AppleTalk Data Stream Protocol


(ADSP) A protocol which provides a simple transport method for data accross a network.

Last updated: 1996-06-18

AppleTalk Filing Protocol


(AFP) A client/server protocol used in AppleTalk communications networks. In order for non-Apple networks to access data in an AppleShare server, their protocols must translate into the AFP language.

See also: Columbia AppleTalk Package.

Last updated: 1998-06-28



(apple-touch-icon.png) Apple's default icon (image) used to represent a website, e.g. when saved as a bookmark or on the home screen of an iOS device such as an iPhone or iPad.

Apple's scheme allows a site to offer images of different sizes so the client can choose the most appropriate one according to its screen size and resolution.

Apple devices and applications completely ignore the favicon.ico de facto standard which, while somewhat quirky in its use of the ico format, has been pretty much universally adopted elsewhere. Conversely, apple-touch-icon.png will be ignored by non-Apple devices, possibly because its 16x16 resolution would look pretty shabby on most smart phones.

The icon can be provided in various different resolutions for different screen sizes and resolutions, e.g. apple-touch-icon-152x152.png for retina iPad with iOS7.

(https://developer.apple.com/library/ios/documentation/AppleApplications/Reference/SafariWebContent/ConfiguringWebApplications/ConfiguringWebApplications.html) Apple documentation.


Last updated: 2018-08-19







An alternative form of apple-touch-icon that is not subject to automatic modification (rounding, drop-shadow, reflective shine) as applied by iOS versions prior to iOS 7. A web page specifies a pre-composed icon by including an element in the <head> like:

 <link rel="apple-touch-icon-precomposed"

The icon can be provided in various different resolutions for different screen sizes and resolutions, e.g. apple-touch-icon-152x152-precomposed.png for retina iPad with iOS7.

Everything you always wanted to know about touch icons.

Last updated: 2018-08-19


<web, testing>

A simplified web browser used for testing applets. You can't browse HTML with it but you can run applets to test them before embedding them in a web page.

Last updated: 2004-08-22


1. application program.

2. function application.

Application Binary Interface


(ABI) The interface by which an application program gains access to operating system and other services. It should be possible to run the same compiled binary applications on any system with the right ABI.

Examples are 88open's Binary Compatibility Standard, the PowerOpen Environment and Windows sockets.

Last updated: 1994-11-08

Application Configuration Access Protocol


(ACAP) A protocol which enhances IMAP by allowing the user to set up address books, user options, and other data for universal access. Currently (Feb 1997) no Internet proprietary products have implemented ACAP because the Internet Engineering Task Force has not yet approved the final specification. This was expected early in 1997.

["Your E-Mail Is Obsolete", Byte, Feb 1997].

Last updated: 1997-05-03

Application Control Architecture


(ACA) DEC's implementation of ORB.

Last updated: 1994-11-08

Application Developer


Someone who does application development.

Last updated: 2013-08-15

application development


Writing computer programs to meet specific requirements; the job of an Application Developer. Application development often includes responsibility for requirements capture and/or testing as well as actual programming (the more limited activity implied by the term programmer).

Last updated: 2013-08-15

application enablement services


IBM-speak for APIs to services such as telecoms, database, etc. within and between address spaces.

Last updated: 1999-01-20

Application environment specification


(AES) A set of specifications from OSF for programming and user interfaces, aimed at providing a consistent application environment on different hardware. It includes "O/S" for the operating system (user commands and program interfaces), "U/E" for the User Environment (Motif), and "N/S" for Network services.


Last updated: 1994-12-07

Application Executive


(AE) An embeddable language, written as a C interpreter by Brian Bliss at UIUC. AE is compiled with an application and thus exists in the same process and address space. It includes a dbx symbol table scanner to access compiled variables and routines, or you can enter them manually by providing a type/name declaration and the address. When the interpreter is invoked, source code fragments are read from the input stream (or a string), parsed, and evaluated immediately. The user can call compiled functions in addition to a few built-in intrinsics, declare new data types and data objects, etc. Different input streams can be evaluated in parallel on Alliant computers.

AE has been ported to SunOS (cc or gcc), Alliant FX and Cray YMP (soon).

ftp://sp2.csrd.uiuc.edu/pub/at.tar.Z. ftp://sp2.csrd.uiuc.edu/pub/bliss/ae.tex.Z.

Last updated: 1992-04-21

Application Integration Architecture


(AIA) DEC's "open standards" specifications.

application layer


The top layer of the OSI seven layer model. This layer handles issues like network transparency, resource allocation and problem partitioning. The application layer is concerned with the user's view of the network (e.g. formatting electronic mail messages). The presentation layer provides the application layer with a familiar local representation of data independent of the format used on the network.

Last updated: 1994-11-28

application lifecycle management


(ALM) A combination of software engineering, requirements management, architecture, coding, testing, tracking and release management.

Last updated: 2009-06-10

Application Portability Architecture


(APA) DEC's plan for portable applications software.

Last updated: 1994-11-28

application program

<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, libraries which exists to support application programs and utility 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 utility programs 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.

Last updated: 2007-02-02

Application Program Interface


(API, or "application programming interface") The interface (calling conventions) by which an application program accesses operating system and other services. An API is defined at source code level and provides a level of abstraction between the application and the kernel (or other privileged utilities) to ensure the portability of the code.

An API can also provide an interface between a high level language and lower level utilities and services which were written without consideration for the calling conventions supported by compiled languages. In this case, the API's main task may be the translation of parameter lists from one format to another and the interpretation of call-by-value and call-by-reference arguments in one or both directions.

Last updated: 1995-02-15

Application Programming Interface

Application Program Interface

Application Protocol Data Unit


(APDU) A packet of data exchanged between two application programs across a network. This is the highest level view of communication in the OSI seven layer model and a single packet exchanged at this level may actually be transmitted as several packets at a lower layer as well as having extra information (headers) added for routing etc.

Last updated: 1995-12-19

Applications Development Manager


(Or "Director") The person in a company who plans and oversees multiple projects and project managers. The Applications Development Managers works with the CIO and senior management to determine systems development strategy and standards. He or she administers department budget and reviews project managers.

Last updated: 2004-03-06

application server

1. <software> A designer's or developer's suite of software that helps programmers isolate the business logic in their programs from the platform-related code. Application servers can handle all of the application logic and connectivity found in client-server applications. Many application servers also offer features such as transaction management, clustering and failover, and load balancing; nearly all offer ODBC support.

Application servers range from small footprint, web-based processors for intelligent appliances or remote embedded devices, to complete environments for assembling, deploying, and maintaining scalable multi-tier applications across an enterprise.

2. <software> Production programs run on a mid-sized computer that handle all application operations between browser-based computers and an organisation's back-end business applications or databases. The application server works as a translator, allowing, for example, a customer with a browser to search an online retailer's database for pricing information.

3. <hardware> The device on which application server software runs. Application Service Providers offer commercial access to such devices.

Citrix Application Serving White Paper.

Application Server Sites, a list maintained by Vayda & Herzum.

The Application Server Zone at DevX,.

TechMetrix Research's Application Server Directory,.

Last updated: 2001-03-30

Application Service Element


(ASE) Software in the presentation layer of the OSI seven layer model which provides an abstracted interface layer to service application protocol data units (APDU). Because applications and networks vary, ASEs are split into common services and specific services.

Examples of services provided by the common application service element (CASE) include remote operations (ROSE) and database concurrency control and recovery (CCR).

The specific application service element (SASE) provides more specialised services such as file transfer, database access, and order entry.

Csico docs.

Last updated: 2003-09-27

application service provider

<business, networking>

(ASP) A service (usually a business) that provides remote access to an application program across a network protocol, typically HTTP. A common example is a website that other websites use for accepting payment by credit card as part of their online ordering systems.

As this term is complex-sounding but vague, it is widely used by marketroids who want to avoid being specific and clear at all costs.

Last updated: 2001-03-26

applications language

Ousterhout's dichotomy

application software

application program

Application Software Installation Server


(ASIS) A service once offered by CERN's IT division that included a repository containing CERN and HEP software and tools in the form of compressed source and documentation.

As of 2014-11-13, the service appears to be dead.


Last updated: 2014-11-13

Application-Specific Integrated Circuit


(ASIC) An integrated circuit designed to perform a particular function by defining the interconnection of a set of basic circuit building blocks drawn from a library provided by the circuit manufacturer.

Last updated: 1995-02-15

Applications Programming Interface

Application Programming Interface

applications software

application program

application testing

system testing

Application Visualisation System

<tool, graphics>

(AVS) A portable, modular, Unix-based graphics package supported by a consortium of vendors including Convex, DEC, IBM, HP, SET Technologies, Stardent and WaveTracer.

Last updated: 1994-11-28

applicative language


A functional language. Sometimes used loosely for any declarative language though logic programming languages are declarative but not applicative.

Last updated: 1995-12-24

Applicative Language for Digital Signal Processing


(ALDiSP) A functional language with special features for real-time I/O and numerical processing, developed at the Technical University of Berlin in 1989.

["An Applicative Real-Time Language for DSP - Programming Supporting Asynchronous Data-Flow Concepts", M. Freericks <[email protected]> in Microprocessing and Microprogramming 32, N-H 1991].

Last updated: 1995-04-19

applicative order reduction


An evaluation strategy under which an expression is evaluated by repeatedly evaluating its leftmost innermost redex. This means that a function's arguments are evaluated before the function is applied. This method will not terminate if a function is given a non-terminating expression as an argument even if the function is not strict in that argument. Also known as call-by-value since the values of arguments are passed rather than their names. This is the evaluation strategy used by ML, Scheme, Hope and most procedural languages such as C and Pascal.

See also normal order reduction, parallel reduction.

Last updated: 1995-01-25



A language which unifies logic programming and functional programming.

["The APPLOG Language", S. Cohen in Logic Programming, deGroot et al eds, P-H 1986, pp.39-276].

Last updated: 1995-01-25


Advanced Peer-to-Peer Networking

approximation algorithm


An algorithm for an optimisation problem that generates feasible but not necessarily optimal solutions.

Unlike "heuristic", the term "approximation algorithm" often implies some proven worst or average case bound on performance. The terms are often used interchangeably however.

Last updated: 1997-10-28

April Fool's Joke

<humour, event>

(AFJ) Elaborate April Fool's hoaxes are a long-established tradition on Usenet and Internet; see kremvax for an example. In fact, April Fool's Day is the *only* seasonal holiday marked by customary observances on the hacker networks.

Last updated: 1995-01-25

A Programming Language


(APL) A programming language designed originally by Ken Iverson at Harvard University in 1957-1960 as a notation for the concise expression of mathematical algorithms. It went unnamed (or just called Iverson's Language) and unimplemented for many years. Finally a subset, APL\360, was implemented in 1964.

APL is an interactive array-oriented language and programming environment with many innovative features. It was originally written using a non-standard character set. It is dynamically typed with dynamic scope. APL introduced several functional forms but is not purely functional.

Dyalog APL/W and Visual APL are recognized .NET languages.

Dyalog APL/W, APLX and APL2000 all offer object-oriented extensions to the language.

ISO 8485 is the 1989 standard defining the language.

Commercial versions: APL SV, VS APL, Sharp APL, Sharp APL/PC, APL*PLUS, APL*PLUS/PC, APL*PLUS/PC II, MCM APL, Honeyapple, DEC APL, APL+Win, APL+Linux, APL+Unix and VisualAPL, Dyalog APL, IBM APL2, APLX, Sharp APL

Open source version: NARS2000.

APL wiki.

See also Kamin's interpreters.

APLWEB translates WEB to APL.

["A Programming Language", Kenneth E. Iverson, Wiley, 1962].

["APL: An Interactive Approach", 1976].

Last updated: 2009-08-11


Ada Programming Support Environment



1. Automatically Programmed Tools.


2. Audio Processing Technology.



An early system on the Datatron 200 series.

[Listed in CACM 2(5):16 (May 1959)].

Last updated: 1995-05-04

Nearby terms:

AOLAOPAOSAPAApacheApache Software FoundationAPALAPAREL

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