a+ To Abvolt (Technology Terms)


A-Plus (A+) is the name of a process, developed by the Computing Technology Industry Association (CompTIA), a large trade group, that certifies individuals for knowledge about and competency in installing, maintaining, customizing, and operating personal computers. The examination is in two parts, the first covering computer hardware and software in general and the second covering a specific operating system, such as Windows 98. The exam is administered by Drake Parametric and there is a fee. A number of companies provide in-house or self-taught preparation for the exam.

CompTIA also sponsors specialized certification for document imaging and a network certification exam. The A-Plus certification is somewhat more basic and less product-specific than other certifications, such as Microsoft’s Microsoft Certified Systems Engineer certifications. An advantage of certification in any industry is that it promotes self-regulation rather than government regulation.


a2b (for short; the site is actually called ”a2b music”) is a Web site that lets you download and play samples or complete songs from popular music recordings, using a music player developed by AT&T. At the a2b music Web site, after first downloading the player, you can then download and play short samples or complete songs from new CD music recordings. The sound, which is said to be "CD-quality," is made possible through MPEG standard Advanced Audio Coding (AAC), a technology that AT&T Labs helped to develop. After sampling a short preview of a song, you can download the entire song from the Web site. Some songs are free and some require an online purchase. You are also invited to purchase the entire CD from the site using secure online ordering. a2b music partners include major recording companies and new releases include those from such artists as Tori Amos, Counting Crows, Willie Nelson, and Bonnie Raitt.

The compression algorithm uses a successor to the MP3 (MPEG-1. layer 3) technology that a2b says offers better stereo sound and such advances as temporal noise shaping and pairwise coding. a2b uses public key cryptography to ensure that only the purchaser can play the music. The player is initially offered for Windows 9x/NT users and is promised for Mac users.

AAA server

An AAA server is a server program that handles user requests for access to computer resources and, for an enterprise, provides authentication, authorization, and accounting (AAA) services. The AAA server typically interacts with network access and gateway servers and with databases and directories containing user information. The current standard by which devices or applications communicate with an AAA server is the Remote Authentication Dial-In User Service (RADIUS). Also see authentication, authorization, and accounting.


AARP (AppleTalk Address Resolution Protocol) is a way to map between the physical hardware addresses of computers, such as those known to an Ethernet or token ring local area network, and their temporarily assigned AppleTalk network addresses.


An AAUI (Apple attachment unit interface) is the 14- or 15-pin port or connection interface on earlier models of Macintosh computers that allowed it to be connected by a short interface cable (or "transceiver") to an Ethernet cable. Later or more advanced models provide a standard registered jack (10Base-T) connection from an Ethernet-capable Macintosh to the Ethernet cable.


An abacus is a manual aid to calculating that consists of beads or disks that can be moved up and down on a series of sticks or strings within a usually wooden frame. The abacus itself doesn’t calculate; it’s simply a device for helping a human being to calculate by remembering what has been counted. The modern Chinese abacus, which is still widely used in China and other countries, dates from about 1200 A.D. It is possible that it derives from the earlier counting boards used around the Mediterranean as early as 300 B.C. An Aztec version of an abacus, circa 900-1000 A.D., is made from maize (corn) threaded through strings mounted in a wooden frame.

There are Japanese and Russian versions of the abacus and several modern "improved" versions.


The abampere (symbolized abA) is the unit of current in the cgs (centimeter/gram/second) system of electromagnetic units. It is the equivalent of one abcoulomb (1 abC) of charge carriers moving past a specific point in one second.

The abampere is a moderately large unit of current, equivalent to 10 amperes (A). In most applications, the ampere, which is the unit of current in the International System of Units (SI), is preferred.

Also see current, cgs or small-unit metric system, and International System of Units (SI).


Abandonware is computer software (such as an operating system, word processor, interactive game, or audio file) that is no longer marketed or distributed by the company that created it, but is obtainable from some other source. Some popular products that have been at least temporarily abandoned include NeXTStep, the operating system for the NEXT computer; OpenStep, its successor; and many interactive games that were replaced by more sophisticated products. In some cases, a company or Web site gets permission from the creator to distribute the abandoned program; but sometimes they don’t. To use abandonware that you download, you often need a license string that the software recognizes as entitling the user to install it. In this case, the downloading site provides a license string that is known to work.

Abandonware is often provided as freeware or as priced shareware.


ABAP is a programming language for developing applications for the SAP R/3 system, a widely-installed business application subsystem. The latest version, ABAP Objects, is object-oriented programming. SAP will run applications written using ABAP/4, the earlier ABAP version, as well as applications using ABAP Objects.

SAP’s original business model for R/3 was developed before the idea of an object-oriented model was widespread. The transition to the object-oriented model reflects an increased customer demand for it. ABAP Objects uses a single inheritance model and full support for object features such as encapsulation, polymorphism, and persistence.

ABCD data switch

An ABCD data switch is a small box that lets you hook up to four devices from one PC serial or parallel port on your computer. For example, if you have both a black-and-white laser printer for regular printing and a color inkjet printer for when you want color, you may want to attach them both to your computer. Perhaps you also have a tape backup drive that needs to be attached. You can connect all of them to the ABCD box which is in turn connected to your PC’s parallel port. By turning a rotary switch on the box to the A, B, C, or D (if you have a fourth device attached) position, you can select the device you want to be active. (You will need to tell your operating system the kind of device that’s attached whenever you switch.)

The data switch can also be used to have up to four computers share the same printer or other device.

This handy little switch costs about $20 (U.S.) and can be purchased in local PC stores.


The abcoulomb (abbreviated abC) is the unit of charge quantity in the cgs (centimeter/gram/second) system of electromagnetic units. It is approximately equal to the charge contained in 6.24 x 1019 electrons.

The force with which two electrically charged bodies attract or repel one another depends on the product of the charges in abcoulombs in both objects, and also on the distance between the objects. If the polarities are the same, the force is repulsive; if the polarities are opposite, the force is attractive. For any two charged bodies, the force decreases in proportion to the square of the distance between their charge centers.

The abcoulomb is a moderately large unit in practical terms, equivalent to 10 coulombs (C). In most applications, the coulomb, which is the standard unit of charge quantity in the International System of Units (SI), is preferred.

Also see charge quantity, cgs or small-unit metric system,and International System of Units (SI).


An abend (a combining of two words, abnormal end, when operator messages were as short as possible) is an abnormal, rather than planned, end or termination of a computer program because of some problem with how it is running. For example, the program may have attempted to address some computer memory space that it was not given the right to address. This term is more common in older mainframe systems than in PC systems.

When used, abend usually refers to the abnormal end of an application program because of application errors. Failure of the operating system is usually called a crash. In smaller systems, the term crash is applied to both application program and operating system failure. A crash also can be caused by hardware failure.


The abfarad (abbreviated abF) is the unit of electromagnetic capacitance in the cgs (centimeter/gram/second) system of units. If a charge of one abcoulomb (1 abC) produces a potential difference of one abvolt (1 abV) in a capacitance, then that capacitance is 1 abF.

A capacitance as large as 1 abF is unknown. It is equivalent to 109 farads. The farad (F) is the standard unit of capacitance in the International System of Units (SI). Even this unit is large; a 1-F capacitor is almost never found in the real world.

In practical applications, the microfarad (mF) and the picofarad (pF) are most often used to quantify capacitance; the abfarad is rarely seen in literature. For comparison, 1 mF = 10-6 F and 1 pF = 10-12 F. Thus, 1 abF = 1015 mF = 1021 pF.

Also see capacitance, farad, cgs or small-unit metric system,and International System of Units (SI).


The abhenry (abbreviated abH) is the unit of electromagnetic inductance in the cgs (centimeter/gram/second) system of units. It is equivalent to 10-9 henry. In a 1-abH inductance, a current that increases or decreases at one abampere per second (1 abA/s) will produce an electromotive force (EMF) of one abvolt (1 abV).

It is unusual to see an inductance as large as one henry (1 H) in the real world, but a 1-abH inductance is small, and is not uncommon. In fact, 1 abH is the equivalent of one nanohenry (1 nH), an often-used unit of inductance, especially at ultra-high and microwave radio frequencies. The henry is the standard unit of inductance in the International System of Units (SI).

In practical applications, the microhenry (mH) and the nanohenry (nH) are most often used to quantify inductance. For comparison, 1 mH = 10-6 H and 1 nH = 10-9 H. Thus, 1 abH = 0.001 mH = 1 nH.

Also see inductance, henry, cgs or small-unit metric system, and International System of Units (SI).


The abohm (symbolized abO) is the unit of electromagnetic resistance in the cgs (centimeter/gram/second) system of units. It is equivalent to 10-9 ohms. When a current of one abampere (1 abA) flows through a resistance of 1 abO, the resulting potential difference across the component is one abvolt (1 abV).

The abohm is an extremely small unit of resistance. In fact, an object with a resistance of 1 abO would make an excellent electrical conductor. In practical applications, the ohm, the kilohm (kO) and the megohm (MO or M) are most often used to quantify resistance. For comparison, 1 abO = 10-15 MO = 10-12 kO. The ohm (O) is the standard unit of resistance in the International System of Units (SI).

Also see resistance, ohm, cgs or small-unit metric system, and International System of Units (SI).


The absiemens (symbolized abS) is the unit of conductance in the cgs (centimeter/gram/second) electromagnetic system of units. It is equivalent to 109 siemens (S).

When a current of one abampere (1 abA) flows through a conductance of 1 abS, the resulting potential difference across the component is one abvolt (1 abV). If the conductance is doubled while the current remains the same, the resulting voltage across the component is cut in half. Conversely, if the conductance is cut in half while the current remains the same, the resulting voltage across the component is doubled. The conductance in absiemens is the reciprocal of the resistance in abohms (abO). The absiemens is an extremely large unit of conductance. In fact, an object with a conductance of 1 abS would make an excellent electrical conductor. In practical applications, the siemens, the millisiemens (mS) and the microsiemens (mS)are most often used to quantify conductance. For comparison, 1 abS = 1015 mS = 1012 mS. The siemens is the standard unit of conductance in the International System of Units (SI).

Also see abohm, conductance, siemens, cgs or small-unit metric system, and International System of Units (SI).

Abstract Syntax Notation One

Abstract Syntax Notation One (ASN.1) is a standard way to describe a message (a unit of application data) that can be sent or received in a network. ASN.1 is divided into two parts: (1) the rules of syntax for describing the contents of a message in terms of data type and content sequence or structure and (2) how you actually encode each data item in a message. ASN.1 is defined in two ISO standards for applications intended for the Open Systems Interconnection (OSI) framework:

• ISO 8824/ITU X.208 specifies the syntax (for example, which data item comes first in the message and what its data type is)

• ISO 8825/ITU X.209 specifies the basic encoding rules for ASN.1 (for example, how to state how long a data item is)

Here’s an example of a message definition specified with ASN.1 notation:

Report ::= SEQUENCE








Bibliography }

In this very simple example, "Report" is the name of this type of message. SEQUENCE indicates that the message is a sequence of data items. The first four data items have the data type of OCTET STRING, meaning each is a string of eight-bit byte (the term OCTET was used rather than BYTE because it can’t be assumed that all computers will have eight bits in a byte). The bibliography data item is another definition named "Bibliography" that is used within this one. It might look like this: Bibliography ::= SEQUENCE









Other data types that can be specified include: INTEGER, BOOLEAN, REAL, and BIT STRING. An ENUMERATED data type is one that takes one of several possible values. Data items can be specified as OPTIONAL (not necessarily present).

Abstract Window Toolkit

Abstract Window Toolkit (AWT) is a set of application program interfaces (APIs) used by Java programmers to create graphical user interface (GUI) objects, such as buttons, scroll bars, and windows. AWT is part of the Java Foundation Classes (JFC) from Sun Microsystems, the company that originated Java. The JFC are a comprehensive set of GUI class libraries that make it easier to develop the user interface part of an application program.

A more recent set of GUI interfaces called Swing extends the AWT so that the programmer can create generalized GUI objects that are independent of a specific operating system’s windowing system.


Abstraction (from the Latin abs, meaning away from and trahere, meaning to draw) is the process of taking away or removing characteristics from something in order to reduce it to a set of essential characteristics. In object-oriented programming, abstraction is one of three central principles (along with encapsulation and inheritance). Through the process of abstraction, a programmer hides all but the relevant data about an object in order to reduce complexity and increase efficiency. In the same way that abstraction sometimes works in art, the object that remains is a representation of the original, with unwanted detail omitted. The resulting object itself can be referred to as an abstraction, meaning a named entity made up of selected attributes and behavior specific to a particular usage of the originating entity. Abstraction is related to both encapsulation and data hiding.

In the process of abstraction, the programmer tries to ensure that the entity is named in a manner that will make sense and that it will have all the relevant aspects included and none of the extraneous ones. A real-world analogy of abstraction might work like this: You (the object) are arranging to meet a blind date and are deciding what to tell them so that they can recognize you in the restaurant. You decide to include the information about where you will be located, your height, hair color, and the color of your jacket. This is all data that will help the procedure (your date finding you) work smoothly. You should include all that information. On the other hand, there are a lot of bits of information about you that aren’t relevant to this situation: your social security number, your admiration for obscure films, and what you took to ”show and tell" in fifth grade are all irrelevant to this particular situation because they won’t help your date find you. However, since entities may have any number of abstractions, you may get to use them in another procedure in the future.


The abvolt (symbolized abV) is the unit of electromotive force (EMF) or potential difference in the cgs (centimeter/ gram/second) electromagnetic system of units. When an EMF of 1 abV exists between two points, then one erg of energy is needed to move one abcoulomb (1 abC) of charge carriers between those two points.

A potential difference of 1 abV will drive a current of one abampere (1 abA) through a resistance of one abohm (abO). Ohm’s Law applies for the cgs electromagnetic units, just as it does for the units in the International System of Units (SI). That is:

E = IR

where E is the EMF in abvolts, I is the current in abamperes, and R is the resistance in abohms.

The abvolt is a tiny unit of EMF, equal to 10-8 volts (V). In most practical applications, the volt, which is the unit of potential difference in SI, is preferred.

Also see voltage, cgs or small-unit metric system, and International Systems of Units (SI).

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