The Dictionary of Multimedia 1999

Terms and Acronyms

Brad Hansen

• Publisher: Routledge
• Year: 2014
• ISBN:
  9781135930653
• Edition: 2
• Topic: Computer Science
• Subtopic: Programming Games
• Index: Computer Science

This book is for programmers, graphic artists, writers, video producers, audio engineers, network managers, hardware technicians, and telecommunications professionals who embrace the complex world of digital media and realize the need for a common language in which to communicate with one another.

A

AAL See ATM Adaptation Layer.

AAP See Association of American Publishers.

A:B:C notation (n.) The standard way to describe relationships between sample rates and color clock rates in digital video formats. Higher rates result in better resolution. Three numbers are used to represent ratios, as follows:

(A)	The basic sample rate compared with the color clock rate.
(B)	The color horizontal downsampling rate compared with the basic sampling rate.
(C)	The color vertical downsampling rate plus 1.

A standard 4:2:2 format indicates that sampling is done at four times the color clock rate, which is 3.58 MHz; that two horizontal chroma samples are taken for every four luminance samples; and that there is no reduction in vertical color resolution (1 + 1).

abend (n.) Abnormal end; an error message indicating the unexpected termination of a program or signal that may be either recoverable or unrecoverable.

ABI See Application Binary Interface.

ABIOS See Advanced Basic Input/Output System.

ablation (n.) The use of a laser beam to burn pits into thin metal film for optical data storage. The process is used to create CDs.

abort (v.) To cancel a computing procedure while in progress.

ABR See automatic baud rate detection.

A-B roll (n.) An editing process in which videotape is played from two tape machines, A and B. As the tapes are rolled, portions of each are dubbed onto a third tape, the composite master. Video editors use this technique to import footage from multiple source tapes. The resulting product is often enhanced by placing transitions between segments from different sources and by using special effects.

ABS See Alternative Billing Service.

abscissa (n.) The x-coordinate, plotted on a graph in response to the input of a function. The y-coordinate is referred to as the ordinate. Pronounced “ab-SISS-a.”

absolute time (n.) The time that elapses from the exact beginning of an audio CD or a digital audio tape (DAT) to any given point in the program material that follows. This information is used to determine the precise start and stop times of a recorded program.

abstract class (n.) In object-oriented programming, a class without instances. Instead, it has concrete classes as subclasses. Example: mammal is an abstract class, and cow is a concrete class.

abstraction (n.) 1. A process in which something is made into a function of something else, or is “parameterized.” Bracket abstractions make a term into a function of a variable. 2. A process of hiding details or generalizing. Example: in abstract syntax, the details of the syntax are ignored.

abstract machine (n.) Software that executes an intermediate language used in a compiler or interpreter. This processor is not intended to be implemented in hardware. It has an instruction set, a register set, and a model of memory. It may be used to make a language implementation easier to port to various platforms. A virtual machine is an abstract machine for which an interpreter exists.

abstract syntax (n.) A form of data structure independent of machine-oriented encoding or language.

Abstract Syntax Notation One (ASN/1) (n.) Language used to encode Simple Network Management Protocol (SNMP) packets. It is also used by Open Systems Interconnection (OSI) protocols for describing abstract syntax, and it is defined in the ISO standard documents 8824.2 and 8825.2.

Abstract Windowing Toolkit (AWT) (n.) The independent windowing, graphics, and user interface toolkit in the Java programming environment.

AC See alternating current.

Accelerated Graphics Port (AGP) (n.) An interface specification developed in 1997 by Intel Corporation. It is based on the peripheral component interconnect (PCI) bus and was designed to facilitate three-dimensional graphics. AGP creates its own dedicated channel, so the graphics controller can directly access main memory, rather than use the PCI bus. This point-to-point channel is 32 bits wide. It runs at 66 MHz but supports data transmission at both the rising and falling ends of the clock cycle for increased speed. The total effective bandwidth is 533 Mbps at double speed (2X) throughput. Three-dimensional textures are stored in main memory, rather than in video memory. Among the requirements for implementing AGP are the OSR 2.1 version of Windows 95 or Windows 98 and a Pentium hardware system with an AGP bus slot. Optional features of AGP include the following:

• Direct Memory Execute mode, which allows textures to be stored in main memory.

• multiple throughput rates: 1X (266 Mbps), 2X (533 Mbps), 4X (1.07 Gbps).

• pipelining, which allows the graphics card to send multiple instructions at once, rather than one at a time.

• sideband addressing, which hastens data transfer by sending command instructions over a separate parallel channel.

accelerator card (n.) A circuit board inserted into a slot on the motherboard that increases the processing speed and performance of the CPU. Production artists use graphics accelerators to increase productivity because these artists must wait for the screen to redraw every time they edit an image.

Acceptable Use Policy (AUP) (n.) An Internet Service Provider’s statement of permissible uses.

acceptance testing (n.) Formal testing conducted to determine whether a system satisfies the stated criteria for a customer.

access (v.) To seek and retrieve information from a hard disk, floppy disk, CD-ROM, or any other digital or analog storage medium.

Access (n.) 1. A relational database application integrated into the Microsoft Office Pro suite. 2. A query language similar to English used in Pick, an operating system developed by VMark Computer, Inc.

ACCESS.bus (n.) Developed by Digital Equipment Corporation, this bus format is based on the Inter-Integrated Circuit serial bus invented by Philips Semiconductors and Signetics. The ACCESS.bus Industry Group supports it as an alternative to the Universal Serial Bus (USB) from Intel Corporation. Software drivers are required to provide the interface between ACCESS.bus hardware and application programs. Physically, ACCESS.bus runs at a relatively low speed over limited distances. It replaces the limited number of specialized ports in a PC with one general-purpose port that supports multiple peripherals in a daisy chain. Pointing devices, modems, printers, a keyboard, and a monitor using the Video Electronics Standards Association (VESA) Display Data Channel (DDC) standard may all be connected on the same bus. It supports up to 125 devices, and each device may operate at a different data rate, up to 100 kilobits per second (Kbps). The maximum cable length is eight meters. Hot plugging, which allows a device to be connected or disconnected without turning off power to a computer, and auto-addressing, which automatically identifies a unit attached to the bus and shakes hands without user intervention, are features of the standard.

Access Control List (ACL) (n.) List of the services available on a server. Each item on the list also has a list of the hosts permitted to use that particular service.

access line (n.) The connecting line between a customer’s premises and the central office of a local telephone company.

access method (n.) The way in which network devices access a network. This method is determined by the Systems Network Architecture (SNA), which controls the flow of network information.

access node (n.) The connection point in a local telephone network at which numerous access lines are consolidated into fewer feeder lines. Access lines are normally multiplexed onto digital loop carrier (DLC) systems supporting T1 transmission. A private branch exchange (PBX) is another type of access node, as are cellular antenna sites and optical network units (ONUs).

access time (n.) The time required to locate and load data from storage after the seek command is issued. Typically, this measurement includes the time it takes the reading head to move between the most distant segments of the medium and to position itself radially. To begin reading or writing, the head must be positioned over the proper sector. This radial motion is called seeking, and the collection of sectors available under multiple heads is called a cylinder. The time it takes for a disk to rotate until the proper sector is located under the heads is rotational latency, which combines with seek time to yield the total access time.

accounting management (n.) The control of individual and group access to network resources to ensure proper bandwidth and security or to assess charges to clients. It is one of five categories of network management defined by the ISO for management of Open Systems Interconnection (OSI) networks.

accumulator (n.) A register in the central processing unit (CPU) where intermediate results are stored. Access to main memory is not as fast as access to the accumulator, which typically has a direct path to and from the arithmetic and logic unit (ALU). Late-model CPUs generally have many registers that may be used as accumulators.

ACD See Automatic Call Distribution or Automatic Call Distributor.

ACI See adjacent channel interference.

ACID test (n.) A test of the atomicity, consistency, isolation, and durability of transaction processing. Passing the ACID test means having a high degree of resilience and recoverability. The term is derived from the process of testing metals with strong acid to determine gold content.

ACIS (n.) A geometric engine owned by Spatial Technologies that is named for its inventors (Andy, Charles, and Ian’s System). It employs a sophisticated object-oriented approach to modeling and is used in several computer-aided design (CAD) programs.

ACK (n.) An acknowledgment character that is returned to a sending device by a receiving device to indicate that the data has been received correctly.

ACL See Access Control List or Association for Computational Linguistics.

ACM See addressed call m...

Table of contents

• Cover
• Half Title
• Title Page
• Copyright Page
• Dedication
• Table of Contents
• Contents: Tables
• Contents: Expanded Definitions
• Contents: Appendices
• Preface
• The Dictionary of Computing and Digital Media
• List of Appendices