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Abacus refers to an ancient tabulating instrument for solving complicated arithmetic calculations. It could be considered the first computer able to handle mathematical equations. Numeric data is inputted by the user through a set of beads strung on a series of rods set in two rows. Most abacus tabulating systems use the decimal system for counting and have the beads on the upper row represent five and on the lower row represent one.
Abstract syntax refers to the independent data structure used by computers in low level machine language encoding.
Access control refers to the ability to control individual user access to a given resource on a computer system or on a network, such as a file. This control is usually given to the root user on a system or the system administrator who has administrator rights on a network.
ACSE stands for Association Control Service Element. This is the method used in OSI for establishing a call between two applications. It verifies the identities and contexts of the application entities, and could also apply an authentication security check.
Address masks are used to select bits of an Internet address for subnetwork addressing. The subnet address mask is 32 bits long. It is commonly referred to as just the subnet mask.
Address resolution is the term for mapping network layer addresses onto certain specific addresses. Two solutions for address resolution are the ARP protocol or creating a subnetwork using a subnet mask.
ADMD stands for Administration Management Domain. This is a specialized message handling system for a public service carrier.
Administrators are special users on a computer system who have certain administration rights that allow them capabilities to configure the system. They usually have access control to the system. To get administration rights the user must log on as the system administrator or as the root user.
Administration rights are management capabilities on a computer system that include certain file permissions, access control, and user account management. These rights allow the administrators to configure and manage the system. To get administration rights the user must log on as the system administrator or as the root user.
ADN stands for Advanced Digital Network. A prototype network architecture that is in development.
ADSL stands for Asymmetric Digital Subscriber Line which is a type of DSL line for network digital communications of data where the upload speed is typically different from the download speed. The download speed will usually be faster. In theory ADSL allows download speeds of up to 9 mbps and upload speeds of up to 640 kbps.
Agent can mean different things in different IT contexts. In OSI networking terminology an agent refers to the part of the management system in a network model that performs information preparation and data exchange on behalf of a network application such as DUA or MTA.
Algorithms are defined sets of procedural steps that constitute a mathematical formula or equation used in a computer programming.
Alphanumeric characters traditionally consisted of the letters of the alphabet and the numbers zero through nine. It now also includes all the other characters that can be typed including punctuation marks, arithmetic symbols and ASCII special characters.
Alt keys refer to two keys on the keyboard that are usually located on the bottom of the keyboard. They will have the letters ALT on them, which stands for alternative. These keys can be used in conjunction with other keys by pressing them both at the same time to perform certain functions in application software. For instance, Alt-Tab is a way for the user to switch between windows on desktops in most operating systems. To do this the user can hold down the Alt key and then tap once on the Tab key.
Alt-Tab is a special key combination activated by simultaneously holding down the Alt key and the then pressing the Tab key once. Alt-Tab is a way for the user to switch between windows on most desktops. The user can hold down the Alt key and tap on the Tab key.
Analog is a form of measurement with a continuous representation. In telecommunications a phone line has an analog connection because it sends an audio wave that is graphed as a continuous line in the form of a wave. Analog measurements can be contrasted with digital measurement where each unit or bit is represented by either the digit zero or one.
ANSI stands for American National Standards Institute. This is the US standardization body used by engineers. ANSI is a member of the International Standards Organization.
AOW stands for Asia and Oceania Workshop. This is one of the three regional OSI groups that implements workshops along with OIW and EWOS.
Apache is a popular open source web server platform that is available to download from the Internet. This platform allows for customizing the computer system for web services such as web hosting, CGI, and DNS to deliver web content.
API stands for Application Program Interface. This is the part of a computer operating system that establishes the interface resources between itself and the complying software application program. It is a set of conventions defining how a service is invoked through a software package. The API environment is important for programmers to understand because it lets them interface with the user on each particular operating system platform. API is comparable to the CGI which is the environment used for web applications.
Application refers to a software program written to provide a specific function to the computer users. Word processors, databases and spreadsheets are examples of three types of commonly used application software.
Application layer refers to the top layer in the OSI network model providing such communication services for web browsers, email and file management.
Application software refers to programs written to provide a specific function to the computer users. Word processors, databases and spreadsheets are examples of three types of commonly used applications.
Archie is a network application service that does file searching over a network or the Internet. It allows the user to locate files that can be downloaded via the FTP protocol. The name Archie is derived from the word archive.
Archives are special files or directories that hold back up data that has been compressed. The archived files can reside in special safe storage areas such as a remote drive on a network or a removable tape drive. When archived the original file or directory is compressed then saved to the back up drive.
ARP stands for Address Resolution Protocol. The Internet protocol is used to dynamically map Internet addresses to physical hardware on local area networks. This protocol is limited to networks that also support a hardware broadcasting protocol.
ARPANET is an acronym for the Advanced Research Projects Agency Network. This was a historic network originated in the early 1970s by the Defense Department. It would eventually become the precursor public network prior to the Internet. Computer scientists created the network to collaborate on projects among several research facilities. It was the first large packet switching network. This success lent to making public network communications more practical. ARPANET was decommissioned in June 1990.
ASCII is an acronym for American Standard Code for Information Interchange. ASCII is an international standard set by the ISO in which all computer characters: numbers, letters, punctuation marks, symbols and control codes are assigned code numbers from 0 to 127. ASCII code includes the special characters available on keyboards. Easily transferred over networks, An ASCII text file is a plain, unadorned text file without style or font specifications.
ASN stands for Abstract Syntax Notation. This is the OSI language for describing abstract syntax. It contains the BER encoding standards.
Assembler refers to a computer utility that transform low level assembly language into machine language to make another program into an executable file.
Assembly language is a low level language where each command statement in software written in the language corresponds to an instruction in the processing. It is a procedural language that has the advantage of high speed, but are tedious to use for programming application software.
Asynchronous is a connection that does not need to be synchronized by a mutual timing signal or timing device. This type of connection is used by a modem over an analog phone line. Most network data communications are synchronous.
Attributes associated with the operating system are pieces of code stored with a file, directory or drive that contains information about the file pertaining to ownership, and what users have read, write and executable rights. Attributes are similar in concepts to file permissions. There are also HTML attributes which are different from file attributes.
Autonomous system is a TCP/IP term for a collection of gateways, as in a subnetwork, defined under one administrative entity and cooperate using a common Interior Gateway Protocol.
Authentication is the process of verifying a user or computer system. This is normally done by the authenticating system by sending security certificates.
Avatars are interactive representation of a person in a virtual reality environment. The term was popularized in the novel Snow Crash by Neal Stephenson. The avatar is a virtual human representation that can then interact over the network or Internet with other avatars within the virtual environment. A virtual reality environment can be created for the Internet using the VRML language.
