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Ian Darwin's Top-100 Computing Glossary

The following list of definitions defines the one hundred or so terms you most need to know.

If you encounter terms that are not covered here, you can check if this page has been updated or you can try the Free Online Dictionary of Computing If you know of a definition that should be added, please mail me (ian at darwinsys.com). This page will be updated every so often; last updated Wed Apr 7 15:33:02 EDT 2021


:-)
A "smiley"; a facial expression turned sidways. Also "-g" for "grin".
802.11
WiFi Wireless protocol standard
Acrobat
See PDF
AGP
Attached Graphic Processor (faster video updating on PCs)
Algol
ALGOrithmic Language (European contemporary of FORTRAN)
Android
An operating environment for mobile devices, using the Linux OS and the Java and Kotlin languages
ANSI
American National Standards Institute
Apache
from "A patchy server"; Apache.org has over a hundred open source projects, best known for their web server (originally a very heavily-patched version of the NCSA web server)
API
Application Programmer Interface (contrast with ABI, B=Binary)
applet
a tiny program (Java applets used to run in web pages)
application
any computer program
ASCII
American Standard Code for Information Interchange
ASCII - American Standard Code for Information Interchange, a 7-bit character set used in most computers, superceded by UTF-8
ASP
Application Service Provider; also (Microsoft) Active Server Pages
AT&T
originally American Telephone and Telegraph
audio mixer
See mixer
bandwidth
Measure of how fast one's connection is
.bat
BATch file (MS-DOS name for command file or shell script)
baud
"Baudot". Normally treated as "bits per second"
BIOS
Basic Input/Output System (ROM-resident I/O routines)
bit
One "0 or 1"-level piece of information; the letter "a" requires 8 bits to store or send
Blu-Ray
Extended version of DVD. Device firmware is written in Java.
BMP
Bit-Mapped Picture (bitmap file format)
browser
The program you use to access the Web
BSD
Berkeley Software Distribution; one of two main kinds of UNIX system (now available in several flavors; OpenBSD, NetBSD, FreeBSD, macOS, etc.
bug
Defect or error in a program
build tool
A program that runs other programs to build an application.
BUNCH
Burroughs, Univac, NCR, Control Data and Honeywell - the 1970's BUNCH opposed IBM's hegemony in the mainframe computer market
byte
A character or other small chunk of information stored in 8 bits (today, but older computers have used 5, 6, 7 or 9-bit bytes)..
C#
Microsoft programming language, originally copied from Java
C
Pioneering computer programming language used to write Unix, and many apps, before C++ and Java
C++
Programming language used in many windowed applications
.ca
Canada (Many other two-letter domains are ISO country codes)
cache
A place where data is kept for reuse; browsers and CPU chips both have 'em
Chrome
(also Chromium), an open-source web browser funded by Google
CICS
Customer Information Control System (long-serving IBM DBMS and database transaction server)
CLI
Command-Line Interface, a terminal-mode connection to a computer system. Seems cumbersome compared with GUI but usually more concise and powerful
client
A desktop machine; a program that uses a server program
clone
To re-write a computer program without using its original source code but retaining its interface.
CMOS
Complementary Metal Oxide Semiconductor (CMOS memory stores BIOS settings on PCs)
COBOL
COmmon Business Oriented Language - widely used by financial sector ~1960s to 2010s
COM
(Microsoft) Component Object Model
.com
Top level domain for COMmercial organizations; "command" (executable file - MS-DOS)
compress
To rewrite a file into a smaller format that can later recreate the original
CORBA
Common Object Request Broker Architecture, an RPC mechanism
CPM
1) Control Program for Microcomputers; 2) Critical Path Method
CP/M
Control Program for Micros; early operating system cloned to make MS-DOS
cross-platform
Able to run on, or to generate programs that run on, multiple operating systems
CSA
Canadian Standards Association
CSV
Comma-Separated Values, a simple data interchange format
CVS
Concurrent Versions System (a larger-scale replacement for RCS)
Dart
A computer programming language, similar to Java, used in Flutter
DBMS
Data Base Management System
DCOM
(Microsoft) Distributed Component Object Model
DEC
Digital Equipment Corporation, an early minicomputer maker, later absorbed by Compaq, which was in turn swallowed by HP
Dedicated
(line) - a permanent link between two computers
Desktop
A computer used by one person at a time; the main view or workarea on a desktop computer's screen.
DHCP
Dynamic Host Configuration Protocol
DHTML
Dynamic HTML
dialup
Working over the telephone with a modem
DLL
Dynamic Link Library
DM
Direct Message, a message sent privately on a forum or social media site
DMA
Direct Memory Access
DNA
1) DEC's Digital Network Architecture; 2) MS-Windows Distributed interNet Applications Architecture
DNS
Domain Name Service
domain
area; see DNS
Domain Name Service
a distributed service for findind a computer's network address if you know its hostname and domain (or vice versa)
DOS
Disk Operating System (used by many manufacturers; IBM 1965). See also MS-DOS
download
Copy a file "down" from a larger device to a smaller (see Uplaod)
drill down
To navigate "down" towards a more-detailed information page. In GUI systems, may be represented by a drop-down control, or by a link to more information.
drop-down
A multiple choice control in a GUI. Usually indicated by a small down-pointing triangle.
DVD
Digital Versatile Disk (initially Digital Video Disk) - CD-ROM format disk with higher density to store several hours of high-res video
EBCDIC
8-bit character set used mainly by IBM mainframe computers
Eclipse
A Java-centric IDE, and, the foundation that supports it and many other projects
Edge
A web browser provided by Microsoft to run on MS-Windows
EFI
See UEFI
EISA
Extended ISA; a bus used on some IBM-style PCs
email
Mail messages send electronically
emoticon
Original "smiley" (qv), now they have Unicode character ("code point") values.
encrypt
To rearrange the data in a message so it cannot (easily) be read by unauthorized persons
.exe
Executable
Facebook
Social Media site
FAQ
Frequently Asked Questions, a list of answers to questions people have asked in the past (except the one you need an answer to right now)
FIFO
First in, first out
filter
Software that reduces the volume of something. Examples: firewalls, SPAM filters, search keyword filters...
firewall
Software that aims to protect you from malicious attack
Flash
Obsolete graphical format from Adobe (Flash was plagued by security flaws most of its lifetime)
Flutter
A portable cross-platform toolkit supporting iOS, Android, MS-Windows, macOS, Linux, and Web from a single code base.
FORTRAN
FORmula Translator; early widely-used programming language, later versions still in use
FOSS
Free and Open Source Software
FP
Functional Programming: programming based on functions with no side effects
free software
Software that you can do what you like with
FreeBSD
"The worlds most scalable operating system": a BSD derivative, used by Apple as basis of Mac OS X and iOS, used by Microsoft to run its Hotmail service for many years
FTP
File Transfer Protocol; an older protocol for copying files; OK for downloading but not for uploading
FUBAR
1: F***ed Up Beyond Any Recognition (attributed to US Military usage in World War 2); 2: Failed UniBus Address Register, pun on #1 name chosen for DEC PDP-11 machine instruction
G
Giga-, 10**9, meaning a thousand million.
GIF
Graphics Interchange Format, an older format for bitmap graphics files.
git
A widely-used VCS
github
A free (Microsoft-funded) site for open source code sharing
GNU
GNU's Not UNIX (recursive acronym), a project to build a Unix-like system
Google
Humungous computer company famous for web search, oft used as a verb
Google Code
A defunct Google site for code sharing.
gopher
An early competitor for HTTP: rarely used now.
.gov
Government (DNS domain for US governmment)
GPL
GNU Public License; like free software but with redistribution conditions
grep
A tool for searching in text. Often used as a verb IRL, e.g., "She grepped the apartment for her car keys."
GUI
Graphical User Interface, common system with windowed desktop, computer and mouse or similar devices
Haskell
A functional programming language
Home page
1) a site's main or welcome page; 2) the default page you see when you start your browser
host
a computer on a network
hostname
a name that can map to e.g., an IP address for a host. Also a service for looking up hosts.
HP
Hewlett-Packard
HTML
HyperText Markup Language, the language that most web pages are written in
HTTP
HyperText Transfer Protocol; protocol used (over TCP) to download web pages, images, etc.
HTTP
HyperText Transport Protocol; protocol used (over TCP) to download web pages, images, etc.
HTTPS
Secure HTTP (HTTP over SSL)
Hyperlink
A link from one web page to another (occasionally to elsewhere in the same page)
hypertext
Text containing hyperlinks
IBM
originally International Business Machines
Icon
1) A small image representing something in a computer desktop or app 2) An computer programming language
IEEE
Institute for Electrical and Electronic Engineers (standards body)
IETF
Internet Engineering Task Force (one of several Internet standards bodies)
Internationalized
Able to be used by people in different languages
InterNet
Interconnected Networks; used to refer to the worldwide connection of networks running the Internet Protocol
Internet Protocol
The protocol used to communicate among computers on the Internet and many local networks
Internet Service Provider
Company that rents you your internet access
IO,I/O
Input/Output
iOS
Apple's operating system for the iPhone
IoT
Internet of Things; connecting small devices to the internet.
IP
see Internet Protocol
iPad
Apple proprietary name for their line of Pads (see Pad).
iPhone
An Apple smartphone running iOS. Not the first smartphone, but the first to be well marketed.
iPod
Apple proprietary name for their line music players (see MP3 player).
IRQ
Interrupt Request Queue
ISA
Industry Standard Architecture (one of 5 expansion buses for desktop computers)
ISO
International Standards Organization; also mistakenly used to mean "ISO-9660", their standard for CD-ROM formatting, as a synonym for CD-ROM-format disk filesystem.
ISP
Internet Service Provider
J2EE
Very-obsolete name for Java Enterprise, which is now Jakarta
Jakarta
Eclipse Foundation project to specify and implement the Java Enterprise APIs, using code base donated by Oracle (formerly JavaEE)
Java
Programming language first used in web pages but now one of the most widely used programming languages, particularly on the server side. Not an acronym; in particular, not "Just Another Vague Acronym" :-)
JavaEE
Previous name for Jakarta, while it was managed by Sun and then Oracle
JavaScript
Programming language used in the browser in most modern web sites; shares some syntax and keywords with Java but is not at all interchangeable with it
JCL
Job Control Language (used for control language on several OSes including IBM mainframes)
JPEG
Joint Picture Experts Group, a newer format for bitmap image files.
JSON
JavaScript Object Notation, now widely-used data interchange format
JSP
Java Server Pages
JUnit
A widely-used Java Unit Testing package
K
Kilo-, 10**3, meaning thousand (either 1,000 or 1,024).
KDE
"K Desktop Environment" (formerly K=Kool, "Kulow" the inventor's first name)
Kotlin
A programming language that looks like simplified and modernized Java
K+P
Kernighan & Pike, book "The UNIX Programming Environment"
K+R
Kernighan & Ritchie, book "The C Programming Language"
library
A file containing multiple subprograms
LIFO
Last in, first out.
link
Any connection. Unix/Linux: extra name for a file. See also hyperlink
Linux
A free operating system patterned loosely on Unix.
login
A name used to authenticate yourself (needed on some sites, and to connect to a server via ssh or other protocol)
LSI
Large Scale Integration (technique for building chips)
LZW
Lempel-Ziv-Welch compression scheme, widely used; patent war fought over it in late 1990's
M
Mega-, 10**6, Million (either 1,000,000 or 1024*1024).
Macintosh
Desktop computers made by Apple; GUI-based; user-friendly; much of Windows 95 was copied from 1980's Macintosh software
macOS
Macintosh Operating System
MacOS X
(the X was pronounced "Ten") - older versions of macOS, partly derived from BSD
Make
A build tool used on Unix, Linux, Windows and Mac
Markup
Adding metadata to a file, e.g, HTML is a markup language that adds formatting information into what is otherwise a plain text file.
Maven
A build tool used in Java
MCA
MicroChannel Architecture, IBM's failed attempt to dominate expansion cards
MCSE
Microsoft Certified System Engineer
MFT
Multitasking with Fixed Tasks (IBM mainframe OS)
Microsoft
A Large computer company based in Redmond, WA.
Microsoft Windows
a family of operating systems for desktop computers
MIF
Maker Input Format, Adobe Framemaker interchange format
.mil
Military (DNS domain for US military)
Mixer
A device or program that blends multiple audio streams into one
modem
(Modulator-demodulator) Box that converts computer signals to telephone noise and back
MoDem (Modulator-demodulator) Box that converts computer signals to telephone noise and back
Mosaic
The first graphical web browser; now defunct; basis of Netscape and Microsoft's browsers
Mouse
A computer input device, first devised by Douglas Englebart at SRI
Mozilla
A software project to take over when Netscape closed down. Main projects are Firefox browser and Thunderbird email program
MP
Multi-processing or multi-processor
MP3
A file format for storing digital audio, such as Music
MP3
MPEG 3 (audio format)
MP3 Player
A small device for playing music files.
MP4
A file format for storing digital video
MPEG
Motion Picture Experts Group (movie format)
MS-DOS
Microsoft Disk Operating System cloned from CP/M; OS distributed with the IBM PC; made Microsoft rich & famous
MS-Windows
Term used to differentiate Microsoft Windows from the general notion of window systems
MVS
Multitasking with Virtual Storage (IBM mainframe OS)
MVT
Multitasking with Variable Tasks (IBM mainframe OS)
NCR
National Cash Register, a firm that got into computers early
NCSA
National Center for Supercomputer Applications (origin of Mosaic and NCSA Web Server, ancestor of Apache Web Server)
NE
Northern Electric (later became NorTel)
.net
1) Network (DNS domain for network related agencies); 2) Microsoft's latest attempt to dominate the world
NetBSD
"The world's most portable operating system": a BSD derivative
Netscape
The first and oldest commercial web browser
News
Messages sent to a topic instead of a list of recipient(s)
NorTel
originally Northern Telecomm, a defunct Canadian telecommunications manufacturer.
NT
New Technology (it was a new try at writing a working MS-Windows system)
NuBus
(not an acronym; a pun on "New") Apple's failed attempt to dominate expansion cards
Oak
Company that made CD-ROM drivers; early name of Java project
Objective C
An OOP extension of the C language, mainly used in Mac OS X
OCaml
A functional programming language
Office Suite
A collection of desktop applications for word processing, presentation, spread sheets, etc.
OOP
Object Oriented Programming; developing sofware in which "classes" of "objects" in the program represent things in the real world
OpenBSD
"The world's most secure operating system": a BSD derivative
Operating System
The program that runs when you start a computer, and is in charge of running all other programs on that computer.
Oracle
A database company that is too big for its britches. Current owner of Java language.
.org
Organization (DNS domain for non-profit organizations)
OS
Operating System; also Open Source
OS/2
Obsolete Operating System # 2 (IBM's answer to MS-Windows)
OSI
Open Systems Interconnection
OSS
Open Source Software; OpenSource Sound System
Pad
Early name at Xerox Parc for a computer tablet
PARC
Palo Alto Research Center, Xerox campus that created the modern computer industry
Patent troll
A person or company that does zero research but buys up patents from dying companies and uses them to sue real companies to extract money without doing real work.
PC
Personal Computer; also Program Counter
PCI
Peripheral Component Interconnect, the major bus for add-in cards on both PCs and Macintoshes today
PDA
Personal Digital Assistant; replaced by smartphones
PDF
Portable Document Format, a file format for sharing printable documents
Perl
Practical Extraction and Reporting Language (aka Purely Eclectic Rubbish Lister) - computer programming language
PERT
Program Evaluation and Review Technique, a management technique for evaluating software development
PGA
Programmable Grid Array (technique for building chips)
ping
to "poke" a host to see if it is both connected and running (not an acronym; sometimes called Packet InterNet Groper but this is not "approved" by the program's inventor, the late Mike Muuss)
PL/1,PLI
Programming Language One; IBM procedural programming language
plugin
A piece of software that extends another, such as a browser
PNG
Portable Network Graphics (patent-free format to replace GIF)
POP
1) point of presence (a remote ISP computer); 2) Post Office Protocol: how many users download their mail
PostScript (PS)
A page description language from Adobe, based on work at PARC. Nowadays PS files are normally converted to PDF.
program
A piece of software; a set of directions to a computer on how to solve a task. Includes OS, applications, apps, etc.
programming language
A language used to express computer software
PROM
Programmable Read Only Memory (BIOS chips used to be installed as PROMs for ease of updating)
protocol
A set of standard for exchanging information (or data)
proxy
A program that stands in for another; often in conjunction with a firewall
public domain
Information or data that anybody can use for anything
query
An inqury that you send to a search enging
Quicktime
Format and plug-in used for movies
R
An interactive data exploration environment, originally cloned from S
RAM
Random Access Memory
RCA
originally Radio Corporation of America
RCS
Revision Control System, a source-code maintenance program
RealAudio
Format and plug-in used for playing audio
register
To give your name, address and email to a site in exchange for a login
RFC
Request For Comments (RFCs are the technical standards for the Internet)
RISC
Reduced Instruction Set Computer
ROM
Read Only Memory
RPC
Remote Procedure Call (Sun, Microsoft, Java and others have their own RPC technology)
RSA
Rivest-Shamir Algorithm
RTF
Rich Text Format, Microsoft word-processor interchange format
RTFM
Read The F***ing (or "Fine") Manual
S
An interactive data exploration environment, written at Bell Labs.
SCO
originally Santa Cruz Operation, reseller and then maintainer of Xenix
SCP
Secure Copy, part of SSH
search engine
A web site that lets you find information on other web sites
Server
A computer used by many people at a time; a program that provides a service
SGI
Silicon Graphics Inc.
SGML
Standard Generalized Markup Language (parent standard of HTML and XML)
Shockwave
Obsolete Format and plug-in used to display animations.
Signal
A protocol for secure messaging, and an App for mobile and desktop that uses it.
SmartPhone
A portable device containing a powerful computer and able to work as a telephone but also run many applications. Main types are Android and iPhone
smiley
A few-byte symbol comprised of ASCII characters that represents a (usually sideways) facial expression, eg., ":-)" Being replaced by emoticons (qv)
SMP
Symetric Multi Processing (i.e., two or more identical SPARC or Pentium chips in one computer)
SMTP
Simple Mail Tranfer Protocol (used to send mail to a server)
SNA
System and Network Architecture (IBM mainframe strategy)
social media
Any site that allows users to login and post/share messages or other information (photos). Popular examples are Facebook, Twitter, Instagram
software
Anything that a computer can interpret
Solaris
Sun's version of UNIX
source code
The form in which computer programs are written, in languages like Java, C++
SourceForge
A free (ad-funded) site for open source code sharing
SPAM
Unwanted email (named after a Monty Python skit).
SPARC
Scalable Processor ARChitecture (Sun's CPU RISC design)
SRI
Independent research organization, originally funded by Stanford University
SSH
Secure Shell, a telnet/FTP replacement
SSL
Secure Sockets Layer (used to encrypt HTTP, making HTTPS. Obsolete; replaced by TLS
Subprogram
A functional unit that can be used by other programs.
subscribe
To register with a service such as mailing list
Sun Microsystems
Former large computer company, home of Java, Solaris, NFS, much more. Swallowed up by Oracle.
SVC
Supervisor Call (IBM mainframe OS term for "system call")
Tablet
A mobile device with a screen size larger than a smartphone.
TCP
Terminal Control Program; the layer above IP and used by e.g., HTTP, to send data
telnet
remote terminal - do not use (use ssh instead)
Test
Running or examing a given subprogram or program to ensure that it works correctly.
Thin client
A computer designed to be permanently connected to a server, using programs from the server, and saving its data on the server
title
The title of a web page; appears in the browser window's title
TLS
Transport Layer Security; replacement for SSL
toolkit
A software development kit, a package of tools and libraries to make a particular kind of applicatino
Troll
To abuse a person or group online, or send useless posts to waste their time; a person who does so.
TSO
Time Sharing Option (IBM's early attempt at a timesharing system)
Twitter
Social Media site
Typescript
An enhanced version of Javascript.
UCE
Unsolicited Commercial Email; another name for SPAM
UDP
Unreliable Datagram Protocol; a "postcard" style protocol for less overhead than TCP; runs over IP; used by DNS
UEFI
A replacement for BIOS
Unicode
Multi-sized character set meant to contain all the world's characters. ASCII/UTF-8 are proper subsets; characters can be 8, 16 or 32 bits.
Unit test
Testing individual pieces of an application in isolation
UNIX
an operating system in continuous use for over fifty years. UNIX machines can be both client and server. Widely used by geeks and to provide internet services. Unix-like systems power both iOS and Android, hence, virtually all mobile devices.
upload
Copy a file from a smaller device to a larger, e.g., a camera to your desktop, your desktop machine to a server
URL
Universal Resource Locator; the address of one page or item on the Web
USB
Universal Serial Bus, modern way of plugging extras into a computer
USENET
Old (user's net?) Collection of "news" sites; predates WWW
UTF-8 - 8-bit superset of ASCII character set
VAX
Virtual Addressing Extension (DEC computer in 1980's/early 90's)
VB
Visual Basic
VCS
Version Control System, sometimes called Program Librarian. Keeps track of all changes made to files such as the source code of a program
virus
A program that attaches to another program (most are harmful!)
Visual Basic
MS-Windows scripting language used to write simple applications
VMS
Virtual Memory System (OS for VAX)
VOIP
Voice Over IP (telephony or voice traffic on the Internet)
WAIS
Another early competitor for HTTP.
Web
World Wide Web
Web page
One page of a web site
webmaster
The person(s) who maintain a given website; the email to send typos/correctsions on the site itself
WhatsApp
A private messaging application, acquired by Facebook.
whois
Service to find out who owns a domain
WiFi
"Wireless Fidelity", an industry term for 802.11 wireless networks. Widely used on mobile devices, smartphones, laptops, tablets, etc.
Wiki
A user-editable web site. Wikipedia was far from the first, but is the best known wiki.
windows
Rectangular regions of a screen; claimed as a trademark by Microsoft
wireless
Communicating without wireless; usually implies radio but can also be Infrared (like TV remote)
word
A series of characters; a storage location in computer memory. Claimed as a trademark by Microsoft.
World Wide Web
the collection of all HTTP servers worldwide connected via the internet
worm
A program that propagates itself from one computer to another
WWW
World Wide Web
xkcd
A popular web comic (xkcd.com)
XML
eXtensible Markup Language; a document authoring language similar to HTML but with more flexibility and stricter coding requirements.
XP
Extreme Programming; also a Windows operating system version
YouTube
A social media site specifically for videos, run by Google
zip
A family of programs that compress and decompress files