A
A cable
Cable type used to attach 50-pin SCSI interface. |
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An instrument for performing arithmetical calculations that uses beads that slide on wooden rods mounted on a wooden frame. |
AC
See . |
Accelerator
The primary chip in the video chipset which handles most of the video processing. The system CPU only sends very basic video commands to the video card, where the accelerator chip translates them into detailed video processing instructions according to the video BIOS. |
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A new interface specification developed by Intel Corporation. Although AGP is based on PCI, it is designed especially for the throughput demands of 3D graphics. It uses a dedicated, point-to-point channel. This allows the graphics controller to directly access main memory. |
Access Method
A specific software routine that stores and retrieves, or transmits and receives, data. |
Access Points (AP)
AP is a communication hub for users of a wireless device that need to connect to a wired LAN. |
Access Time
The delay between the time the drive receives the read command and when it actually begins reading the data bits from the track. The specification given for a drive is actually an average of several different random tests conducted by the manufacturer. The actual times will always vary, depending on where the read/write head is in relation to the data on the platter. |
Active matrix LCD panel
Standard portable computer screen type featuring an enhanced version of the passive matrix display using thin film transistors (TFT).
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Active termination
SCSI termination using voltage regulators to induce a regulated termination voltage. |
Acronym
Term for a word that is formed by combining some parts (usually the first letters) of some other words. For example, modem is the acronym derived from the words. It is pronounced as if it were a word instead of just a series of letters. |
Adaptec
The SCSI device controller manufacturer who developed the SCSI-2 non-hard drive peripheral control interface called the Advanced SCSI Programming Interface or ASPI. |
Adapter Bracket
Brace or prop used to support and attach expansion cards to the chassis. It is a subassembly of the chassis. |
Adapter Plate
Metal cover used to seal holes over unused expansion brackets. It prevents dust from entering the case and helps maintain good air flow inside the case. |
Address Bus
Data bus used by the CPU to carry data that identifies the memory locations where the data bits are being sent to or retrieved from. |
ADSL
Short for asymmetric digital subscriber line, a new technology that allows more data to be sent over existing copper telephone lines. |
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All non-hard drive SCSI peripherals require software drivers to provide full emulation of the SCSI-2 interface. To help make the situation with drivers more standardized, Adaptec developed this emulation specification so that manufacturers could more easily develop these drivers. |
AGP
Abbreviation for accelerated graphics port.
See |
AGP Port
Also known as the Accelerated Graphics Port, this was introduced by Intel in 1997. It is a special high speed video slot with direct access to the processor bus, and therefore, the CPU. AGP was developed in response to the trend towards greater and greater performance requirements for video. |
AGP (Accelerated Graphics Port)
An interface specification developed by Intel Corporation especially for the throughput demands of 3D graphics. AGP uses a dedicated point-to-point channel, and allows the graphics controller to directly access main memory. |
AGP Slot
Abbreviation for Accelerated Graphics Port slot. The AGP is a high speed graphics port created by Intel, that has a direct connection between the display monitor and memory. |
AGP Video Card
A circuit board that plugs into the accelerated graphics port on the motherboard in order to give a PC display capabilities. It is designed to accommodate the throughput demands of 3D graphics. |
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Algorithmic Language. It was a programming language developed in the late 1950s used for scientific computations. |
ALGOL-60
A variant of ALGOL developed in 1960. See |
Algorithmic Language
See |
Alphanumeric Key
Keyboard keys that represent letters and/or numbers. |
Altair
An Intel 8080-based machine made by MITS and introduced to the public in 1974. It was the first popular microcomputer kit. |
Alternating Current
Electricity that is transported over long distances, usually by power lines in the form of current that reverses its direction regularly and continually. It is the form of electrical power found in residential and commercial buildings. |
AMD
Advanced Micro Devices. Intel-clone-producing computer manufacturer. |
Analog-To-Digital Converter
The device that converts analog (sound-based) tones and pulses into digital (binary-based) data for computer use. |
Analytical Engine
Second computing device conceived by Charles Babbage. The Analytical Engine was designed as a programmable and adaptable machine. Data and instructions were to be entered by punched cards. It was designed to store numbers and was a decimal device that could handle all four arithmetic functions. The Analytical Engine was never built. |
Antenna
A metallic device or piece of equipment used in sending and/or receiving electromagnetic waves (radio signals). It is the port specializing in converting radio-frequency (RF) fields into alternating current (AC) and vice-versa. The most common type of wireless antenna is the dish antenna. |
Anthropologist
A social scientist who specializes in the study of human beings in relation to distribution, origin, classification, and relationship of races, physical character, environmental, and social relations, and culture. |
Anti-Static Bag
Bag used to prevent static electricity from passing to electronic components inside. They are used to help prevent Electrostatic Discharge (ESD). |
Anti-Static Mat
Made of anti static material, an anti-static mat provides a grounding sources, absorbing static electricity and preventing damage to electronic components. |
Aperture Grill
A masking design composed of many hundreds of fine metal strips that run vertically on the inside of the monitor screen from the top to the bottom. It serves to focus the electron beam on the correct dots much like the shadow mask. |
Apple II
An 8-bit personal computer from Apple Computer invented by Steve Wozniak. |
Apple Computers
Apple Computers, Inc., of Cupertino, CA, manufactured the Apple I and II and, later, the Macintosh line. Steve Wozniak and Steve Jobs founded Apple Computers in 1976. |
Arbitration
The process the SCSI host adapter uses to set priorities in handling multiple read/write requests simultaneously from contending drives on the bus. It sets these priorities based on the SCSI ID of the devices, from 0 to 7 in order of increasing priority. |
Archeologist
A person who studies material remains of past human life, activities, and culture. Fossil relics, artifacts, and monuments are some examples of what an archeologist might study. |
Architecture
The physical construction of the components in a computer system. |
ARCnet cards
ARCnet cards help to support the ARCnet data link protocol. ARCnet functions at the OSI model's physical level and uses the token passing access method. |
Arithmetic Functions
Operations relating to or involving numerical computations or calculations. There are four basic arithmetic functions: addition, subtraction, multiplication, and division. |
Arithometer
Calculating machine developed in the first quarter of the 19th century by Charles Xavier Thomas de Colmar. Colmar’s device could perform all four of the basic arithmetic functions: addition, subtraction, multiplication, and division |
ASPI
See . |
ASPI Manager
The actual ASPI interface module loaded to supply the SCSI-2 emulation to non-hard drive devices. This is always loaded into memory before the specific ASPI compliant driver written by a manufacturer for their specific device. |
Asynchronous
Not synchronized. That is, not occurring at predetermined or regular intervals. The term asynchronous describes communications in which data can be transmitted intermittently rather than in a steady stream. |
Asynchronous Communication
Bi-directional data transmission between two devices in which the length of time between transmitted characters varies. Serial port communication is asynchronous. |
Asynchronous DRAM
Asynchronous DRAM is not synchronized to the system clock. |
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Also called ATAPI, this is an extension to the ATA-2 standard that specifies the device controller characteristics for non-hard drive IDE devices such as CD-ROM, tape drives, etc. |
AT Attachment Standards
The standard that governs integrated drive electronics technology. Subsequent standard revisions appear in ATA-X format. |
AT Command set
The defacto standard body of commands that communication programs send to the modem that manipulate its internal logic. Also known as the Hayes command set since it was first developed by Hayes Microcomputer, Inc. |
AT&T
Founded in 1885, AT&T is the largest long-distance telephone carrier in the U.S. A portion of AT&T--AT&T WorldNet--is one of the world\'s largest Internet service providers, offering dial-up access to more than 700 cities and 150 countries. |
AT/Desk
A type of form factor associated with older technologies. The term form factor refers to the physical dimensions of a system unit. |
AT Tower
A type of form factor associated with older technologies. The term form factor refers to the physical dimensions of a system unit. |
ATA-2
Short for AT Attachment Standard No. 2, this is an update of the IDE/ATA standard; a disk drive implementation that integrates the controller on the disk drive itself. Also known as EIDE and Fast-ATA, depending on the manufacturer. |
ATA Packet Interface
Same as ATAPI. The extension specification of the ATA-2 standard that defines the device side characteristics for non-hard drives devices such as CD-ROMs or tape drives. |
ATAPI
- ATA Packet Interface. See ATA Packet Interface.
- AT Attachment Packet Interface. See
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Athlon processor
Proprietary CPU of Advanced Micro Devices, Inc. |
ATM
A network technology designed to support real-time voice, real-time video, and data. |
Attenuation
Degradation in signal quality due to interference. Reduce the risk of attenuation by following manufacturer maximum cable length guidelines. |
ATX
A type of form factor in current use. It is a development of the Baby AT specification with the motherboard rotated 90 degrees in the chassis. The CPU and SIMM sockets have been relocated away from the expansion card slots. Therefore, all the slots support full-length cards. Most Pentium Pro boards use this form factor.
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ATX Motherboard
An ATX motherboard is a standard, desktop computer, motherboard specification currently in widespread use. The ATX specifications superceded the place of the Baby AT, an earlier motherboard version. |
ATX Form Factor Footprint
Size and configuration of case and internal components that meet the specifications for the ATX. |
Automating
Converting to largely automatic operation. |
AUI (Attachment Unit Interface)
AUI is the portion of the Ethernet standard that specifies how a cable is connected to an Ethernet card. AUI is a 15-pin connector on a NIC and is also known as a DIX connector.
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B
B cable
Cable used to attach 68-pin SCSI interface to 16- and 32-bit SCSI buses. B cable is obsolete, P cable is the industry substitute. |
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A type of form factor associated with older technologies. |
Baby AT Form Factor Footprint
Size and configuration of case and internal components that meet the specifications for the Baby AT. |
Backbone
Computer network that links several networks. FDDI is a common backbone network. |
Back-Order
Business term used when demand outstrips supply so that insufficient numbers of the product are available. |
Backup Power Supply
Device providing electric power when the regular power source fails. Two main kinds of backup power supplies: and |
Backward Compatible
Describes an upgraded machine that can handle all the commands of previous versions. |
Ballistic
The science that deals with the motion and impact of projectiles, such as bullets, missiles, or bombs. |
Balun (BALanced UNbalanced)
This device or transformer connects a balanced line to an unbalanced line, i.e.: a twisted pair to a coaxial cable. |
Bandwidth
The difference between the highest and lowest frequency available for transmission in a communications system. |
Bank
Groups of slots or socket connectors designed to mount one or more similar components to the motherboard. |
BASIC
See . |
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The BIOS contains the code required to control the display screen, disk drives, keyboard, serial communications, and a number of miscellaneous functions. The BIOS makes it possible for a computer to boot itself. |
Basic Mechanical Switch
Also referred to as the pure mechanical switch, it is the simplest type of keyboard switch, incorporating a basic mechanical switch that uses metal contacts in a transient contact arrangement. This switch is expensive to build, but has excellent tactile feedback. |
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The number of electrical oscillations that occur each second in digital communications. Each oscillation encodes one of information. The baud rate indicates the number of bits per second that are transmitted. |
B Cable
A cable used to attach a 68-pin SCSI interface to 16- and 32-bit SCSI buses. The B cable is obsolete. The P cable is the industry preference. |
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A simple language designed by John G. Kemeny and Thomas E. Kurtz at Dartmouth College in 1963. It first ran on an IBM 704 in May of 1964. It was designed for quick and easy programming by students and beginners. |
Bi-Directional
Term used to refer to lines or cable over which data can move in two directions. Examples include a data bus and a telephone line. |
Binary
A numbers system based on only two digits: 0 and 1. All values are expressed as combinations of these two numbers. For example, the letter A is expressed as 1000001. |
BIOS
See |
BIOS Cacheable
Copying BIOS instructions from a slow ROM chip to the system's high speed cache. |
BIOS Features Setup
Advanced features that control the behavior of the system. |
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A bit is the smallest piece of information that a computer can understand. It takes eight bits to equal one byte. A bit is either a 1 or 0. |
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Also called BPS. This is the same as baud rate. See . |
Blackout
Failure of electric power for a general region. |
Block Mode PIO Cable Select
One of two key interface signals used to indicate the status of two connected drives on an IDE controller channel. This allows the master and slave IDE drives to coordinate their data transmissions on the bus. |
BNC
The British Naval Connector is a circular connector located at each end of a coaxial cable. |
Boot, Booting
To load and initialize the operating system on a computer. |
Boot Partition
A primary partition on a hard drive that has been set to active (bootable) by the partitioning utility. The BIOS searches for the operating system’s bootstrap loader on this partition. |
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Another term for the master boot record. This is the very beginning of the hard drive (cylinder 0, head 0, sector 1) with the initial boot program that the system BIOS loads to begin the boot process. |
BPS
Bits per second. See . |
Branch Prediction
Technique that enables the CPU to analyze and predict what future needs will occur to allow data to process more efficiently. |
Bridges
One kind of equipment used to connect segments of a single network or to connect similar entire networks to each other. |
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A type of power event. Any decrease that falls below the normal voltage carried by a power line. See , , , and . |
Bubble-Jet Printer
Another term for inkjet printers. See Inkjet Printer. |
Buffer
A temporary storage area. It is usually located in RAM. It acts as a holding area and enables the CPU to manipulate data before transferring it to a device. Common buffers include those for printers, keyboard drivers, and disk buffers for operating systems such as DOS. |
Bugs
An error or defect in software or hardware that causes a program to malfunction. |
Bus
An assortment of wires or circuit paths through which data is transmitted from one part of a computer to another. The term bus usually refers to the internal bus that connects all internal computer components to the CPU and main memory (RAM). |
Busmastering DMA
Direct Memory Access transfers performed directly by a device without help from the motherboard's DMA controller. See DMA.
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Bus Circuitry
Motherboard circuits that connect components with a system's processor and memory. |
Bus Controller Chip Set
Chip set that governs the processor and memory buses. A collection of integrated circuits that are designed to be used together for some specific purpose, in this case control of data transmission on a bus. |
Bus Mastering
Term that refers to a feature that enables a controller connected to the bus to communicate directly with other devices on the bus without going through the CPU. Bus mastering is supported by most modern bus architectures, because it improves performance. |
Busmastering DMA
Direct Memory Access transfers performed directly by a device without help from the motherboard\'s DMA controller. See DMA. |
Bus Network
Network in which computers are arranged "down a line" without a centralized hub. |
Byte
A byte is a unit of data that consists of eight bits. It is the amount of disk space needed to store one character of information (e.g., a letter, digit, or punctuation mark).
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C
C Language
A programming language designed at AT&T Bell Labs in the early 1970s. Partly due to its simplicity, efficiency, and flexibility and partly due to its distribution with Unix, C became immensely popular outside Bell Labs after about 1980 and is now the dominant language in systems and microcomputer applications programming. |
CAD applications
Refers to Computer Aided Design software, most often used by engineers, architects, and others in graphical design work. |
Cable
A cable used to attach a 50-pin SCSI interface. |
Cable Modem
A modem designed to operate over coaxial cable lines owned by cable TV companies. This is not a true modem, but uses a network adapter interface to link to the Internet through the high bandwidth coaxial cable medium. Another promising emergent technology. |
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A method that allows a computer to determine which drive is the master and which is the slave according to the position of the cable. Cable select requires a special type of cable, and jumpers must be set to the "cable select" position. |
Cache
A system for storing frequently accessed information for faster response. Cache memory on your motherboard is extra-fast RAM that keeps a copy of the most recently requested bits from regular RAM. |
Cache Memory
A memory bank bridging main memory and the CPU. With cache memory instructions can be executed and data can be read at higher speed. Level 1 (L1) cache: memory bank built into the chip. Level 2 cache (L2): a memory chip group on the motherboard. |
Caddy
A small plastic carrier with hinged lid required by certain types of CD-ROM readers to hold a compact disc. CD-ROMs with caddy load mechanisms are more sturdy and last longer than those with the cheaper tray mechanism. |
Calculation
The act or process, or the result, of computing, reckoning, or estimating. Computation. |
Calculator
A machine that can perform arithmetic functions. |
Canadian Standards Association
Canadian standards development and certification organization. |
Capacitor
An electronic device that can store electrical charge. It is the basis of a dynamic RAM cell. Capacitors are also used for power supply smoothing or decoupling. |
Card-Edge Connector
Slotted I/O expansion slot on the motherboard. It is designed so that the edges of the expansion card pins align with pins in the slot. The pins in the slot connect to the data lines of the I/O bus. |
Carrier Detect (CD)
Signal generated by the modem, letting the computer know the modem is on-line. |
Carrier Sense Multiple Access With Collision Detection (CSMA/CD)
An Ethernet feature that, after listening for silence, sends packets, resending them if a collision is found. |
Case
The plastic housing which encloses and protects the Cathode Ray Tube and associate electrical circuitry. |
Cathode Ray Tube (CRT)
A glass cylinder with an electron gun at the rear that emits electron beams to activate a phosphor-coated screen to create an image. CRT is used to describe any monitor that uses a cathode ray tube. |
CAU (Controlled-Access Unit)
A Token Ring network’s central hub |
CCITT
Consultative Committee on International Telephone and Telegraph. See |
CD
Compact disk. See . |
CD-ROM
Compact disk read-only memory. See. |
CD-ROM Drive
A peripheral device that uses a read-only optical storage medium to access up to 682mb of data, including text, audio, video, and graphics. These devices can have either an IDE or SCSI interface. |
Celeron
Somewhat slower than Intel Pentium models but based on the same P6 architecture, the Intel CPU designed for lower cost personal computers.
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A CPU, sometimes referred to as a processor or microprocessor, is a microchip about the size of a thumbnail that acts as a computer's brain. Common examples of CPUs include Intel's Pentium and 486DX. |
Centronics Connector
The first type of SCSI device interface was the low-density 50-pin Centronics connector. |
CGA
Color Graphics Array. The first graphics standard introduced in 1981, it became obsolete when VGA was introduced in 1987. |
Channel
Each IDE interface cable is a channel. Current ATA standards allow two devices per channel. |
Character
In serial communications, a byte of data (eight data bits) preceded by one start bit and ended by one stop bit. |
Characters Per Second
The measure of speed of dot matrix printers. How many characters of a certain quality the printer can output each second. |
Chassis
A metal frame inside the desktop of tower case that serves as the structural support for electronic components of a computer. It houses the circuit boards and wiring and contains slots for expansion boards. It also includes drive bays, motherboard mounting plate, cutouts for rear case connectors, power supply, speaker, front panel, long adapter card supports, and main cover attachment points. |
Chipset Features Setup
Section of BIOS allowing the user to fine-tune control parameters for the main system chipset. |
Circuit Board
A thin, rectangular plate, usually made of silicon, on which chips and other electronic components are affixed. There are several of types of circuit boards in modern computers. They are often called cards or adapters. Examples of integrated circuit boards include the motherboard and expansion cards. |
CISC
Most personal computers use the Complex Instruction Set Computer architecture, for which the CPU supports up to two hundred instructions. |
CISC processors
A CPU that supports CISC architecture. |
Cleaning
The first step in the laser printer printing process--a runner blade wipes the drum free of any residual toner from previous printing job. |
Cleaning Blade
Rubber arm inside a laser printer, responsible for cleaning any residual toner from the photosensitive drum. |
Client
A term used for a user’s microcomputer while on a network. |
Client/Server
A LAN or WAN architecture using servers or workstation computers to make requests and the server to fulfill requests. |
Clock Signal
Voltage supplied by the motherboard to a quartz crystal to make it vibrate at a predetermined speed. The vibrations of the quartz crystal help control the speed of the CPU. |
Clusters
Also called allocation units. Groups of disk sectors that are used by the FAT file management system to manage files. |
CLV
Constant linear velocity. See cmd.exe. The Windows NT command processor |
CMOS
A commonly used term for the stored system configuration settings that are set up in BIOS. |
CMOS Chip
Complementary metal oxide semiconductor design chip. It is a battery powered memory and clock chip that is used to store system clock settings and configuration data. Another term for this is RTC/NVRAM chip. |
CMOS Setup
Another term for the BIOS or system setup utility. Technically incorrect, but used because the system setup configuration is stored in the CMOS chip. |
CNR (Communication Networking Riser)
A CNR is a motherboard expansion slot that can assume the role of a Network Interface Card (NIC) and sound card. CNRs are an improvement over AMRs (Audio Modem Risers). |
Coaxial
Coaxial cable (co-ax) is high-capacity cable used in data communications, network connections, and video equipment. |
Coaxial Cable
High-capacity cable used in communications and video components. Coaxial (co-ax) cable contains an insulated solid center wire surrounded by a solid or braided metallic shield, wrapped in a plastic cover. |
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Common Business Oriented Language. A programming language for simple computations on large amounts of data. It was developed in April of 1960 and is still widely used today. |
LocalTalk
The name of a LAN access method from Apple. LocalTalk uses twisted-pair wires and a daisy chain topology. |
Cog
A tooth or catch for imparting or receiving motion, as on a gear wheel. |
Cold War
Hostility and conflict that started in the 1940's between the U.S. and Western Europe against the Soviet Union and its Eastern European allies. |
Color Gradation
The perceptual factor involved in color display design. Digital displays can only display a limited range of color shades. Analog displays allow an almost infinite number of color shades. This is why IBM switched to analog color displays with its introduction of the VGA standard in 1987. |
Collisions
When information is sent by two Ethernet-network computers at the some time, the data "collides." The network waits a random amount of time, then tries to resend the data. |
COM Port
The name of a serial communications port in DOS systems. Four serial port names are supported in DOS. They are COM1, COM2, COM3, and COM4, however most PCs have only two physical serial ports. In those cases COM1 and COM3 refer to the same port, while COM2 and COM4 refer to the another port. Therefore, if there are two devices, one of which is attached to COM1 and the other to COM3, they cannot be used simultaneously. |
COM1 and COM2
Serial communications ports on the motherboard that can be configured for a number of different devices. |
command.com
The MS-DOS command processor. One of the three MS-DOS operating system files that the MS-DOS bootstrap loader searches for in the root directory of the boot disk and loads into memory. |
Command Interpreter
Another term for command processor. |
Command Processor
The central command file for the operating system kernel which accepts and executes the operating system commands. This file is accessed directly from a command prompt. |
Command Prompt
Also called the command line. The text-based screen interface for an operating system. Some of the advanced features of operating systems such as Unix, Windows NT, and Linux require exiting from the GUI shell to this interface for keyboard input. |
Command Queue
The memory buffer a SCSI host adapter uses to line up read/write requests from SCSI hard drives or devices until the host adapter processor has time to attend to it. |
Common Business Oriented Language
See . |
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5.25-inch plastic-coated metal platters on which digital data can be stored. |
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A computer peripheral device that utilizes a read-only optical storage medium to access up to 682mb of data, including text, audio, video, and graphics. These devices can have either an IDE or SCSI interface. |
Computer
An electronic device created to enable users to input, manipulate, store, and output information. |
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Hardware input device similar to a mouse that is usually used to enter data on a small portable computer. |
Computer Programmer
Software engineer who designs, writes, and tests computer programs. |
Communication Networking Riser (CNR)
A CNR is a motherboard expansion slot that can assume the role of a Network Interface Card (NIC) and sound card. CNRs are an improvement over AMRs (Audio Modem Risers). |
Conditional Control Transfer
The EDVAC system contained a special type of machine instruction that allowed the program sequence to be stopped at any point and then restarted. |
Conditioning
Third step in the laser printer, printing process. A negative electrical charge is evenly applied to the printer's drum. |
Conductive
Describes the capacity of a substance to transmit electricity, heat, sound, etc. |
Conductor
A material that transmits electricity, heat, sound, etc. |
Configure, Configuration
This term refers to the way that a computer's operating system is set up or the variety of components that make up a system. The term can refer to either hardware or software, or a combination of both. In some instances, configuration is accomplished by setting switches and jumpers. |
Connector
Another term used for electrical leads. |
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The ability of the CD-ROM disk to spin at different rates of speed, ensuring that the amount of data that goes past the lens assembly during a fixed increment of time remains constant. Since the track data is expected to always move past the read laser at the same speed, the actual disk spin speed must be varied to compensate for the different size of the tracks over the diameter of the CD. Sometimes, you will see this referred to as the CLV. |
Constant Angular Velocity
This is an alternative to CLV, where the track data is moving past the read laser at different speeds, depending on where the track is physically located over the diameter of the CD. Tracks towards the center of the disk play faster than those towards the edge because the rate of spin is kept constant. Sometimes this is referred to as the CAV. Few CD-ROMs actually use this technology. Most use a combination of both CLV and CAV. |
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Older name for the International Telecommunications Union. See |
Contact
Juncture of two electrical conductors through which a current can pass. A physical surface designed to complete or interrupt a circuit. |
Control Arms
The hard drive's appendage for suspending read/write heads above the disk platter surface. |
Control Circuitry
The dedicated (a device devoted to a single task) electrical component that reads in the output from the video card RAMDAC chip and controls the electron beam scanning on the CRT. External controls can manipulate the brightness, contrast, screen shape, and color of this output. |
Copycat Chips
Other proprietary microchips that behave identically. |
Cover
Usually a one-piece component, screwed to the computer's chassis, to protect internal parts and promote airflow. |
CPS
Characters per second. See Characters Per Second. |
CPU
See definition for and . |
CPU Cache
A CPU cache is a memory bank that bridges the CPU and main memory. A CPU cache is considerably faster than main memory and allows data and instructions to be read at a higher speed. |
CPU Socket
The connector which attaches the CPU to the motherboard. Different processors require different styles of sockets. |
CRC
Short for Cyclical Redundancy Check. See |
CRT (Cathode Ray Tube)
A glass cylinder with an electron gun at the rear that emits electron beams to activate a phosphor- coated screen to create an image. CRT is used to describe any monitor that uses a cathode ray tube. |
CSA
See Canadian Standards Association. |
CSEL
Short for Cable Select. See . |
Cut-Sheet Paper
An individual page paper fed into the printer engine one sheet at a time from a manual or tray feeder (i.e., letter- or legal-size paper). |
Cyrix
Computer manufacturer that produces a Pentium-clone computer, the Cyrix 6x86. |
Cylinder Head Sector (CHS)
The first strategy used for hard disk drives to address data. CHS had a maximum of 504 MB. |
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An error-detection technique used by modems on every block of data sent between them. Detected errors force the resending of the bad data. |
D
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Term used to describe the bus topology of floppy drives, IDE hard drives, and especially SCSI hard drives, where every device is arranged linearly in a long line on a ribbon cable. |
Daisy-Chain Configuration
Set up of devices on a system so that components are strung together in such a way that signals move serially from one to the other. An example is the SCSI bus system. |
DASP
Drive Active/Slave Present See |
Data
In the world of computers, data refers to any information that goes into or is taken from the computer. |
Data Compression Standards
The ITU standard for data compression that provides a mathematical algorithm to compress the data to as much as one quarter its normal size over a modem connection. The dominant data compression standard supported in all modern modems is the ITU V.42bis standard. |
Dataflow Analysis
Identifying and documenting how data moves around an information system. |
Data Integrity
The accuracy of data after being transmitted or processed. |
Data Terminal Ready (DTR)
A signal indicating the system is ready to receive a data transmission. |
dB
See |
DC
See . |
DDR SDRAM (Double Data Rate RAM)
DDR is considered to be one of the most promising alternate methods of memory access in development. Several RAM accesses can be executed consecutively with DDR through a process know as interleave. |
Debounce
A programming routine used by the keyboard controller to neutralize the side effect of rapid keyboard switch pressing when the switch actually bounces rapidly on-and-off the circuit contacts. |
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Measurement of the intensity of a sound wave. The unit of measurement of audio level. In computing, it is a comparative measure of the strength or level of signal power. Decibel is frequently abbreviated as Db. |
Decimal Number
Common base 10 numbering system using the digits 0-9. |
De Facto
As a matter of fact. Truly. Really. |
Defect Mapping
The process of configuring the hard drive to locate and compensate for drive errors to help assure data integrity |
Deflection Coil
The cathode-ray tube’s portion that deflects the electron beam. The deflection cause the beam to strike a specific screen area. Also called yoke.
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Defrag or Defragmentation
Defragging is rewriting files to a disk so that they are in continuous order. |
Default Gateway
The term default gateway refers to the IP address of the default router used when sending data from one network to another. See gateway.
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Delete Key
Computer keyboard key used to remove characters and other objects. It generally removes the character that is located immediately beneath the cursor. |
Demodulation
Conversion of analog signal into digital data by varying the frequency of the electronic wave. |
Detents
Fixed increments of movement on a hard disk track to which the stepper motor moves the heads across the media. |
Developer Unit
A smaller roller near the drum that feeds toner onto the drum from a storage bin above it. The storage bin is called the toner hopper. |
Developing
The fifth step in the laser printing process. Toner is exposed to the printer's drum. Toner application causes an image to form within the uncharged fields of the drum. |
Device Driver
A specialized software program that controls a device. Drivers are required for every device. Many drivers come with the operating system. Other devices require that a driver be loaded when they are connected to the computer. The driver acts like a translator between the device and programs that use the device. Each device’s driver has a set of specialized commands that only it knows. Most programs access devices by using universal commands. Then, the driver accepts the universal commands from a program and translates them into specialized commands for the device.
A program that controls a device. There are three types: BIOS, BIOS extension, and operating system. They load in order of BIOS core drivers, BIOS extension drivers (adapter boards), and operating system drivers. |
Diagnostic Software Disk
A disk that contains a program designed to run system diagnostics and display the results on a monitor or in a printout. Diagnostics are generally available for memory, processors, disk storage, operating systems, and peripherals. |
Diagnostic Test
Usually, any software implemented test used to diagnose problems on the system. A typical example of a diagnostic test includes those implemented by anti-virus software. |
Difference Engine
First automatic mechanical calculator. Only approximately one-seventh of the steam driven device that was conceived by Charles Babbage was ever built. The device was intended for the production of mathematical table. |
Diffuse
To pour out and cause to spread. To cause to flow on all sides. |
Digital
Describes signals and information consisting of electronic energy pulses that represent the bits and bytes of binary code. Increasingly, digital transmissions are replacing analog transmissions. |
Digital Camera
A camera that takes pictures without using film; instead it stores the snapshots as digital files in its memory. |
Digital Computer
A computer that operates with numbers expressed directly as digits. In such computers, data is represented in the form of numerical digits. |
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Device used to measure and test voltage, resistance, and amperage of electrical components. Also referred to as DMM. |
Digital Signal Processor (DSP)
A very fast digital-processing chip used in devices like sound cards, cellular phones, and high-capacity hard disks. |
Digital Subscriber Line (DSL)
A high speed Internet connection available through telephone companies for personal and business applications. |
DIMM (Dual In-Line Memory Module)
A small circuit board that holds memory chips. A DIMM as a 64-bit path to the memory chip. A Single In-Line Memory Module (SIMM), which has only a 32-bit path to the memory chips. |
DIMM Slot
The connector used to install a DIMM onto the motherboard. A slot on the motherboard that is designed to be used by a DIMM board. |
DIMM Socket
The connector used to install a DIMM onto the motherboard. A socket on the motherboard that is designed to be used by a DIMM board. |
Diode
A semiconductor device which conducts electric current running in one direction only. This is the simplest kind of semiconductor device. A diode has two terminals and a single PN junction. |
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Electrical current that travels in only one direction as opposed to alternating current. It is generally used in electronic circuits. |
Direct Memory Access (DMA)
Means by which data moves between a system device, such as a disk drive, and system memory without direct CPU control. DMA frees up the CPU for other tasks. |
Direct Memory Access Channel
Means by which data moves between a system device such as a disk drive and system memory without direct control of the CPU. By doing this, it frees up the CPU for other tasks. |
Disk Change Signal
A signal sent to the floppy drive controller to advise it of the status change when a diskette is inserted or ejected into a floppy disk drive. If the signal is not received again before the next read/write operation, then the system assumes the diskette has not been changed. See also diskette changeline. |
Disk Drive
Computer peripheral that reads data from and writes data onto a disk. A disk drive resembles a record album player in that it rotates the disk very fast and has one or more heads that read and write data. |
Disk Platters
Disk platters are media disks that store data in the hard drive. The disks are typically constructed of a rigid composite material covered with magnetically sensitive, thin-film media |
Diskette Changeline
Pin 34 on the floppy disk drive interface and floppy drive controller used to exchange a special signal called the disk change signal. |
Diskette
Short for floppy diskette. The removable media disk used by floppy disk drives to read/write data. |
Display Monitor
Another term for video display monitor, monitor, or video monitor. |
Display Power Management System
Also called DPMS, a power management signaling specification developed for monitors by the Video Electronics Standards Association. Allows a computer with a DPMS-enabled BIOS to monitor a video display for inactivity and power it down until used. This requires a DPMS aware operating system however. |
Displayable Resolution
Part of a manufacturer’s Resolution specification which states the maximum physical resolution a monitor model can display. This is distinguished from the maximum Recommended resolution. |
DMA
Means by which data moves between a system device such as a disk drive and system memory without direct control of the CPU. Direct Memory Access frees up the CPU for other tasks. |
DMM
See |
Docking Station
Docking station offers portable computer users the best of both worlds: the advantages of portability with the opportunity to use a portable as a traditional desktop.
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Dot Matrix
A type of impact printer that creates characters and graphics by striking pins against an ink ribbon. The striking pins print closely spaced dots in the appropriate shapes of characters. |
Domain Name System (DNS)
Domain Name System or DNS is Internet computer-locating software that allows users to find specific computer users on the Internet by either a domain name or IP address. |
Domain System
A system of grouping computers and devices to be administered in a network setting. |
Dot Pitch
This is the distance between adjacent sets of red, green, and blue dots in a given pixel. Dot pitch defines how fine the dots are that make the image on a video display. The smaller the distance between the dots, the sharper the image. |
Dots
The smallest elements of a Cathode Ray Tube. These are the small red, green, and blue phosphorus spots on the inside of the monitor screen. |
Double-Sided
This term refers to memory chips that are located on both sides of the SIMM. |
DRAM
Abbreviation for dynamic random access memory. DRAM is a form of semiconductor random access memory (RAM) that stores information in integrated circuits containing capacitors. Unlike ROM, DRAM loses its content when the power is turned off. |
Drive
A device used to write to and/or read information from magnetic platters or disks. Types of drives include hard disk drives, floppy disk drives, CD-ROM, and optical drives. |
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One of two key interface signals used by hard drives on the IDE bus. The drive active/slave present signals the presence of a slave drive at startup and is used by both drives after startup to indicate whether they are active. |
Drive Bracket
Brace or prop used to attach the drives the chassis. |
Drive Commands
Device commands in the system BIOS used to manage hard drives through the controller interface. For IDE drives, these are based on the original WD1003 interface with enhancements defined in the ATA-2 standard. For SCSI drives, these commands are most often in the SCSI Host Adapter BIOS. |
Drive Geometry
A term used to describe the way a hard disk drive structures data into platters, tracks, and sectors. |
Drive Select 0
One of a set of two jumpers located on the circuit board of a floppy drive. When closed with a bridge, it selects the floppy drive as Drive A on the floppy drive bus. See DSO. |
Drive Select 1
One of a set of two jumpers located on the circuit board of a floppy drive. When closed with a bridge, it selects the floppy drive as Drive B on the floppy drive bus. See DS1. |
Drive Status Light
Indicator light (LED) on the front bezel of the case that tells whether a drive is active or at rest. If the light is on, the drive is being accessed. The absence of any light indicates that the drive is not in use. |
Driver
A device-specific program routine helping to connect a specific peripheral device to the operating system. |
Drum
Magnetic media storage device |
DS0
Drive Select 0. See Drive Select 0. |
DS1
Drive Select 1. See Drive Select 1. |
Dual CPU systems
Dual CPU systems are computers that possess a multiprocessing architecture featuring multiple CPUs residing in a single cabinet, sharing the same memory. |
Dual In-Line Memory Module (DIMM)
A small circuit board that holds memory chips. A DIMM as a 64-bit path to the memory chip. A Single In-Line Memory Module ( SIMM), which has only a 32-bit path to the memory chips. |
Dual-Ported
A memory architecture design for video memory, especially VRAM and WRAM, which has two access paths, and can be written to and read from simultaneously. This allows it to be accessed by both the chipset processor and RAMDAC chip simultaneously for greater video throughput. |
Dust Plate
Another term for an adapter plate.
A plate that covers each hole on the back of the computer that is not being used by an expansion card. |
Duster
Compressed air or carbon dioxide in a can used to blow dust off electronic components. |
Dvorak
A not-widely-used keyboard layout designed in the 1930s by August Dvorak, University of Washington, and his brother-in-law, William Dealey. |
DVD
Digital Versatile (or Video) Disks holds between 4.7 – 17 GB, which is enough for a full length motion picture.
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DVD support
Any computer software or hardware support designed to help a computer use the DVD family of optical discs and related technology. |
Dye Sublimation Printer
This printer contains a roll of transparent film, comprised of page-size color panels that use high heat to transfer the colors one at a time to the paper. |
Dynamic Electricity
Electricity that results from the flow of electric charge. |
Dynamic Execution
Combination of three features: Multiple Branch Prediction, Dataflow Analysis and Speculative Execution. |
Dynamic IP Address.
A current-session-only Internet Protocol address |
E
ECHS (Extended Cylinder Head Selector)
A process used in conjunction with an enhanced BIOS to split the hard disk drive's geometry, allowing the system to save data beyond the 504MB barrier. |
Econo-Mode
A low resolution print mode for inkjet printers which prints at a lower density using less ink. |
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Abbreviation for enhanced capabilities port. See |
EDO
Extended Data Out DRAM or EDO-DRAM. It is a type of DRAM designed to access nearby memory locations faster than FPM DRAM. |
EDO RAM
See . |
EEPROM
Electrically Erasable Programmable Read Only Memory (EEPROM) can be erased and reprogrammed (written to) repeatedly when charged with higher than normal electrical voltage. Unlike EPROM chips, EEPROMs do not need to be removed from the computer to be modified. |
Efficiency
In a power supply, the ratio of output power to input power. |
EGA
Enhanced Graphics Array. The second graphics standard introduced in 1984, it became obsolete when VGA was introduced in 1987. |
EIA
Acronym for |
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Enhanced Integrated Drive Electronics. Same as the ATA-2 standard. See |
EIDE Interface
The 40-pin interface connector that is keyed by the removal of pin 20 on the male drive connector site for the IDE drive and the motherboard controller. |
Electrically Erasable Programmable ROM (Read Only Memory)
EEPROM can be erased and reprogrammed (written to) repeatedly when charged with higher than normal electrical voltage. Unlike EPROM chips, EEPROMs do not need to be removed from the computer to be modified. |
Electromagnetic
Pertaining to or exhibiting magnetism produced by electric charge in motion. |
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Interference that is caused by electromagnetic signals. It can cause reduced data integrity and increased error rates on transmission channels. |
Electromechanical
Any electromechanical device that converts electrical energy to mechanical energy. |
Electron
A sub-atomic particle consisting of a charge of negative electricity. |
Electron Gun
This device produces an electron beam that is found in a computer monitor. |
Electronic Handshake
A series of electronic signals sent between devices indicating the devices are ready to transmit or receive data. |
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This association contains members from various electronics manufacturers and is based in Washington, D.C. The association sets standards for electronic components. |
Electronic mail (e-mail)
The transmission of text messages and attachments over an electronic network. |
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The flow or spark of electricity that originates from a static source, such as a carpet, and arcs across a gap to another object. The direction in which the electrical charge moves is from a positive to a negative. |
EMI
See |
E-mail
Electronic mail, or E-mail, refers to both to both general e-mail features, as well as specific messages sent by way of e-mail. |
Emulate
To try to be the same as, especially by imitating. |
Energy Star
An energy conservation standard created by the U.S. Environmental Protection Agency for computer peripherals. Devices that are tested to draw no more than 30 watts when inactive can be certified for this standard and display the logo. |
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A parallel-port standard for PCs. It supports bi-directional transmission of data between the PC and devices attached to is such as printers. It is about ten times faster than the pre-existing standard. It offers similar performance to the EPP. |
Enhanced IDE
Another variant term for EIDE or Enhanced Integrated Drive Electronics. See or |
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An update to the older IDE or ATA standard approved in 1995. The EIDE/ATA-2 specification covers the interface signals on the 40-pin IDE connector, the drive commands issued by the BIOS, cable specifications, and drive configuration circuitry. The improvements support data transfer rates of about 12 megabytes per second and storage devices of up to 8.4 gigabytes. |
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A parallel port standard for PCs. It supports bi-directional communication between the PC and devices attached to it such as printers. It is about 10 times faster than the pre-existing standard. It provides performance that is similar to that provided by ECP. |
Enhanced Port Replicators
Additional PC card slots, enhanced video and sound capabilities that are not native to portables or standard port replicators. |
Enhanced Small Device Interface (ESD)
A type of legacy hard disk drive interface that predated IDE technology. |
EPA (Environmental Protection Agency)
EPA is the official government agency that is committed to protecting the natural environment and provides information on current initiatives, key issues, compliance and enforcement and much more. |
EPP
Abbreviation for enhanced parallel port. See |
EPROM
See . |
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A special type of memory that retains its contents until it is exposed to ultraviolet light. Once exposed to ultraviolet light, its contents are cleared. This makes it possible to reprogram the memory. |
Erasing
Second step in the laser printing process. Any residual charge on the printer's drum is neutralized. |
Ergonomic
Ergonomic devices are designed and arranged with special attention to their safe and efficient human use. |
Error Correction
A variety of techniques used to test the reliability of data input or output and correct errors, either through rebroadcast of the faulty data or reconstruction from predictable patterns of data. |
Error Correction Standard
The ITU V.42 standard for error correction in modem communications. See |
Error-Correcting Code Memory
Quick-acting memory testing and correcting system based on "checksums," adding seven bits to each 32-bit word. |
ESD
See . |
Ethernet
Currently the most popular technology for computer networking. An Ethernet can take either a bus or star configuration. |
Expansion Adapter
Another term for the device that serves as an interface between the system unit and the devices attached to it. Other terms used to describe this device are circuit board, circuit card, or card. |
Expansion Bus
Assortment of wires and protocols that allows the computer to grow or expand. This expansion is accomplished by adding printed circuit boards to the motherboard. In the past, PCs used an expansion bus that was called the ISA bus. Because this produces somewhat of a bottleneck, today nearly all PCs use a PCI bus for performance and an ISA bus for backward compatibility. |
Expansion Card
A printed circuit board that can be inserted into a computer to give it added capabilities. Examples of expansion cards include video adapters, graphics accelerators, sound cards, accelerator boards, and internal modems. They are sometimes called adapters, cards, add-ins, and add-ons. |
Extended Cylinder Head Selector (ECHS)
A process used in conjunction with an enhanced BIOS to split the hard disk drive's geometry, allowing the system to save data beyond the 504MB barrier. |
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A dynamic RAM chip that improves the performance of fast-page, mode memory by about 10%. EDO RAM eliminates wait states by keeping the output buffer active until the next cycle begins. |
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Extended Data Output RAM, or EDO RAM, is a type of dynamic RAM chip that improves the performance of fast-page, mode memory by about 10%. EDO RAM eliminates wait states by keeping the output buffer active until the next cycle begins. |
Extended Data Output RAM
A type of DRAM that is faster than the usual DRAM. EDO RAM can copy an entire block of memory to its internal cache unlike conventional DRAM that only allows one byte to be read at a time. It is faster because the memory can collect a new block to send while the processor is accessing the cache. For EDO RAM to operate faster, the cache controller must support a transfer mode known as pipeline burst. |
Extended data out DRAM (EDO DRAM)
A DRAM available for both SIMM and DIMM configurations. |
Extended Industry Standard Architecture
Introduced in 1988, the EISA extends the 16-bit ISA to 32 bits. EISA accepts ISA cards. |
External Drive Unit
A peripheral device such as a floppy disk drive that attaches to the system unit and is used for input and output such as storage of data. |
External I/O Connector
A type of device that is external to the motherboard and can be accessed from the outside of the case. It serves as an interface between the I/O bus on the motherboard and an external component or device such as keyboards, mice, printers, and modems. |
External Lever Switch
An outdated lever-type power switch found on older AT-type power supplies. |
External Modem
A modem that connects to computer system through the computer's serial port |
F
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Another term for tractor feed paper. See Tractor Feed Paper. |
FAQ
See . |
Fast Ethernet
Fast Ethernet is a high-speed (100Mbps) version of an Ethernet LAN. |
Fast SCSI-2
A variant of the SCSI-2 standard that supports data rates of 10Mbps over an 8-bit bus, and uses the 50-pin interface connector. |
Fast Wide SCSI-2
An extension of the SCSI-2 standard sometimes called SCSI-3. It uses 16-bit bus and supports data rates of 20Mbps over the wide SCSI-2 68-pin interface connector. |
Fault Tolerance
A computer system’s ability to recover from a variety of hardware failures including CPU failure, power supply failure, and hard drive failure. A properly configured fault tolerant system will loose no data and suffer no down time during a failure. (Some slow down will occur under certain conditions.) |
FAT
File Allocation Table. See File Allocation Table. |
FAT 32 file system
The FAT 32 file system is a 32-bit version file allocation table that reduces cluster waste, relocates the root directory on a hard disk, and utilizes a backup copy of the FAT table. Overall, a FAT32 system provides important safeguards in the event of a hard disk failure. |
FCC
Federal Communications Commission. The FCC, an independent government agency, is the licensing and regulatory authority for television, radio, wire, satellite, and cable in the United States. |
FDC
Floppy drive connector on the motherboard. Multi I/O parallel connector. |
fdisk.exe
A DOS program file used to partition and activate hard drives for operating system install. Usually operates on any FAT or variant hard drive, but will not on other operating system file system disks such as Windows NT NTFS or Unix AFS. |
Fiber Distributed Data Interface (FDDI)
One technology for computer networking, and typically used to link several networks. Based on a ring configuration without a central hub. |
Fiber Optic Cable
Fiber optic cable is a communication medium using infrared and LED-emitted light waves to transfer data. |
Fifteen (15)-Pin Mini D-sub
The standard 15-pin connector used by the cable for connecting the video monitor to the video card |
Filament
A cathode in the form of a metal wire in an electron tube. |
File Allocation Table
A index table C:\Program Files\Microsoft FrontPage\temp\table.htm that the operating system C:\Program Files\Microsoft FrontPage\temp\operating_system.htm uses to locate files on a disk drive. A file may be divided into many sections that are scattered around the disk since they are written randomly to clusters. This index table tracks the pieces. |
File Transfer Protocol
FTP. Procedure to download files from or upload files to remote computer systems. |
Finder
An integral part of early Macintosh operating systems. A finder manages icons, controls the clipboard and scrapbook files, and allows files to be copied. The <b>MultiFinder</b> is now an inherent part of the Mac OS system. |
Finite
Having definite or definable limits. Having a limited nature or existence. |
FireWire
This is Apple Computers’ version of the IEEE 1394 standard that provides a single ‘plug-and-play’ socket connection interface between a computer and its peripherals. |
Firmware
A computer program, (a set of instructions), whether data or programs, that is stored permanently in read only memory (ROM or semi-permanently in EPROM) and can remain operating without the use of electrical power. |
Fixed Disk Drives
Alternate term for hard drives utilized by the IBM Corporation. |
Fixed Refresh Rate
Design specification for a display monitor which has only one scanning frequency. This limits the monitors ability to display higher resolutions without image flicker due to the fixed vertical and horizontal scan rates. |
Flash BIOS
A type of flash memory chip called an EEPROM, which allows the BIOS to be updated by means of files from the manufacturer. |
flash-EPROM
A special type of read-only memory, EPROM retains its contents until exposed to ultraviolet light. Once exposed to ultraviolet light, EPROM contents are cleared, making it possible to reprogram the memory. |
Floppy Disk
Another term for diskette. |
Floppy Disk Drive
A peripheral device that reads and writes floppy disks. A type of disk drive that has removable storage media called floppy diskettes. Commonly called a floppy drive. |
Floppy Drive Controller
Electronics that control the floppy disk drive and negotiate the passage of data between the floppy disk drive and the computer. |
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A method of managing the rate at which the host system sends data to the modem. This is done either in modem hardware whereby the modem sends Request to Send/Clear to Send (RTS/CTS) signals on dedicated wires in the cable (if an external modem) or card/edge connectors (if an internal slotted modem) to the host system to control the data flow rate. |
Fluffing
Fluffing is the act of running a thumb or finger over the edge of a paper stack to reduce static electricity before a print job. |
Flux
The magnetic polarity of the particles in the thin film media of hard drive platters. |
Flux Pattern
The pattern of flux reversals or transitions encoded into the thin film media of the hard drive platters. The timing of these transitions represent the stored data bits. |
Flux Reversal
A switch in the magnetic polarity of the particles in the thin film media of hard drive platters. |
FM
Frequency modulation synthesis—synthesizing sound by creating a wave close to the original sound’s wave. |
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Another type of mechanical switch very similar to the basic mechanical design and formerly very popular in keyboards. It uses a foam shim with foil laminated on the bottom in place of the metal plate to strike the contacts. The foam tends to become moist over time, corroding the metal contacts, and loses its rebound. Because of this, this type is not seen much anymore. |
Foam Element
See . |
Font
Character set with a common typeface, style and weight. |
Forced Perfect Termination (FPT)
SCSI termination that can stifle signal overshoot and undershoot. |
Form Factor
The physical dimensions of a system unit. Two computers with the same form factor are physically interchangeable. |
format.com
A DOS program file used to create a FAT file system on a hard drive or floppy diskette. |
FORTRAN
Short for Formula Translator. FORTRAN is a programming language developed in the 50s, and is still used today for numerical and scientific applications. |
Fortune 500
Business magazine. Any company labeled a Fortune 500 company is large and well-known. |
Frame Buffer
This is the place in video memory where the information is stored about the video image itself. Each pixel on the screen has associated with it typically 4 to 32 bits of data that represent its color and intensity. The larger the frame buffer, the better performance of the video card if there is sufficient total video RAM since other video processing will also use video memory. |
Frequency Modulation (FM) Synthesis
Synthesizing sound by creating a wave close to the original sound’s wave. |
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Information posted periodically to high-volume newsgroups in an attempt to answer questions that are common to the user. |
Freeware
Freeware is any software that is distributed free of charge. |
Front Case Bezel
Portion of a computer's case located at the front through which the CD ROM and floppy drives are accessed and on which various LED indicators, the reset button, and the ON/OFF switch are located. |
Front Bezel
Panel that covers the face of a drive. As its name indicates, it is located on the front of the computer. |
FTP
File Transfer Protocol. Procedure to download files from or upload files to remote computer systems. |
Fuel Cell Battery
This battery generates electricity by converting a fuel into electricity. |
Full Duplex
Updated sound card characteristic: like a telephone line, sound can travel in both directions, and do so simultaneously via two channels. |
Full Duplex Mode
The ability of high performance modems to send and receive data over a phone line at the same time by sending data bits out on one wire while receiving data bits on the other wire in a two wire phone line. |
Full Tower
Largest of the Tower form factors. |
Fuse
A device used as part of the power supply’s internal overload protection circuitry. When the maximum allowable current is exceeded, the fuse bears the brunt of the overload and intentionally blows. |
Fuser
In a laser printer, a pair of very hot rollers in the paper path that fixes the toner into the paper with heat and pressure after it leaves the drum assembly. |
Fusing
The seventh step in the laser printing process. Paper is passed rollers that apply pressure and heat to use the toner to the paper's surface. |
Fusing Rollers
(Also know as a fuser) The fuser applies pressure and heat to fix toner to the paper being printed. |
G
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Alternate term for the stacked way that read/write heads are attached to the end of the head actuator assembly of a hard drive. They move in unison as a "gang". |
Gateway
The term gateway is often used differently depending on context. The term default gateway refers to the IP address of the default router used when sending data from one network to another. The term gateway (in a different context) refers to a translator between networks. In general, a gateway is a network point that acts as an entrance to another network. |
Gear
A toothed wheel, or cogwheel. |
Germanium
A grayish white hard brittle metalloid element that resembles silicon and is used as a semiconductor. Originally discovered in 1886, it received little attention until its electron-transfer properties led to its use in the creation of the first semiconductor transistor 1948. |
Gigabyte
One gigabyte equals 1,024 megabytes or 1,073,741,824 bytes. It is often abbreviated as G or GB. |
Ghost images
Phenomenon common to passive matrix LCDs when an image slowly fades away after the charge is withdrawn from a particular gridline within the screen. |
Graphics Accelerator
The primary video adapter chip, the graphics accelerator handles most of the video processing. |
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The use of pictures and text, rather than text alone, to represent the input and output of a program. The term also refers to an operating system interface that takes advantage of a computer's graphics capabilities to provide an easy interface for users. |
Graphics Tablet
Hardware input device that has a touch sensitive surface. When the user draws on the tablet's surface using a special pen, it relays the image drawn to the computer where it can be manipulated in a graphics application.
See |
Gray Code
A binary notational system of positional information burned into the disk media during manufacture. This is used by the servo mechanism of a hard drive to guide the head actuator mechanism with read/write heads. |
Ground
Any contact point that is electrically neutral. |
Grounding
See Ground. |
Grounding Strap
Device, usually worn on the wrist, which prevents the buildup of an electrical charge. It is used to help prevent ESD. |
GUI
See .
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H
Half-Duplex
A device that is capable of non-simultaneous bi-directional communication. |
"Handshake" Mode
Request/acknowledgement method that a SCSI host adapter uses to negotiate an asynchronous data transfer with a SCSI device on the bus. |
Hard Disk Drive
A high volume disk storage device with fixed, high density, rigid media. Also referred to as a hard drive. |
Hard Disk Drive LED
A LED (Light Emitting Diode) that is usually located on the front of a computer case. It is plugged into a connector on the motherboard and is used for monitoring hard drive activity. When the hard drive is in use, the light should be on. |
Hard Disk Drive Light
Another term for hard disk drive LED. |
Hard Drive Controller
Electronics that control the hard disk drive and negotiate the passage of data between the hard disk drive and the computer. |
Hard Drive Interface
A hard drive together with hardware and software necessary for the hard drive to exchange data with the computer's motherboard |
Hardware Interrupt
Another term used for an interrupt request channel an IRQ. |
Harmonic Distortion
A change in an electrical signal that occurs periodically. |
Hayes Command Set
Another term for the AT command set. See AT Command set. |
HDA
Head Disk Assembly. See . |
HDD Low Level Format
Used to reset the drive geometry on older hard drives, low level formatting is NOT used on current hard drives. |
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The sealed chamber of a hard drive containing the platters, spindle motor, heads, and head actuator mechanism. This is a single logical component only serviceable by the manufacturer. |
Head Actuator Assembly
The hard drive mechanism composed of the read/write heads, the arms that hold them, and the voice coil actuator which moves these accurately across the hard drive platters. |
Heat Sink
Heat-absorbing material used for chip-generated heat absorption on computer motherboards. |
Hemostat
Medical device designed to compress a bleeding vessel and stop blood flow by pinching and locking in place. A hemostat has a handle like scissors, a locking device, and ends with a tweezer-like serrated face to prevent slippage. |
Hexadecimal Number
Base 16 numbering system using the digits 0-9 and A through F. Often used to represent the binary numbers that computers use. |
High-Level Formatted
Creating a file system for operating system use and to store files. |
High Voltage Differential (HVD)
A SCSI device with an auxiliary wire carrying a high voltage electrical signal allowing the SCSI cabling to exceed its standard 6-meter limit. HVD devices are not compatible with any single-ended or low voltage differential devices. |
Hold Time
Time during which a power supply’s output voltage remains within specification following the loss of input power. |
Hollerith Cards
Punch cards developed by Herman Hollerith to store instructions or programs for his calculating device. |
Horizontal Scan Rate
The rated speed at which the scanning electron beam can write the image across the screen horizontally. |
hot-swappable
The ability to swap devices while the system is on. |
Hot Wire
Ungrounded lead wire used to connect the transformer and electrical devices or appliances by means of an electrical outlet and power plug. |
HTML (hyper-text mark-up language)
The document format most commonly used on the World Wide Web to write and create Web pages. |
HTTP protocol
A communications protocol that functions to connect separate Web page servers across the World Wide Web. |
Hub
Another term for the spindle on which are mounted the disk platters in a hard drive. The spindle is powered by the spindle motor to rotate the platters. The term hub is also used in networking to refer to a connection that joins network communication lines in a star configuration. |
Hybrid chip
A hybrid refers to a combination of features from two or more microchips. |
Hypertext link
A database system that allows files to be linked. Links provide users access to those files. |
Hypothetical
Suggested as true, but not necessarily so. |
I
i.link
A standard for a high speed external bus that can connect up to 36 devices with 400Mbit/second transfer rates. |
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The International Business Machines Corporation is the world's largest computer company that dates back to Herman Hollerith’s adding machine.
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IBM-Compatible Computers
Personal computer that follows the industry standard developed by IBM. |
IBM PC
Personal computer developed by IBM in 1981 using modular components. It had 360K floppy disks and became the industry standard for a whole series of personal computers that are said to be IBM compatible. |
IDA
Abbreviation for Infrared Data Association. This is a group of device manufacturers. They developed a standard for sending data by means of infrared light waves. |
IDC (Insulation Displacement Connector)
This connector eliminates the need to strip the insulation of a cable instead it cuts or slices through the insulation around a cable to make a connection. |
IDE
Integrated Drive Electronics. See . |
IDE HDD auto detection
BIOS will scan and report drive profiles which can then be accepted (if they match the specifications of your specific drive) or rejected. |
Identify Drive
An ATA-2 standard drive command issued by the system BIOS to the EIDE hard drive, requesting it send a 512 byte data block identifying its make, model, and drive geometry.
A drive command sent out by the BIOS to the IDE hard drive when the Hard Drive configuration feature is set to AUTO configuration. The command queries the drive for its operating parameter or drive geometry, which is then supplied to the BIOS for the boot-up operation. |
IEEE (Institute of Electrical and Electronics Engineers)
The need for unique hardware addresses is why this committee established a standard for hardware addresses, and provides NIC manufacturers with media access control addresses. |
iMac
An iMac is an Apple computer introduced in 1998, prized by consumers for its low-price, Internet readiness, and unique look. |
Impact Printer
The class of printers in which the printheads physically strike the paper. |
Industry Standard Architecture (ISA)
ISA "cards" attach to a computer's motherboard to expand the computer's functions. A sound card, for example, allows a computer to produce sound effects, music, and voices. |
Information Age
Period following the Industrial Age that was made possible by the invention of the integrated circuit in 1958 and marked by the ability to transform information into electrical form and transmit it reliably and rapidly over long distances. |
Infrared Connection
IrDA port on a motherboard. Port that enables the transmittal of data from one device to another without the use of cables provided there is a clear line of sight between the two devices. |
Ink Dispersion
This is the process by which ink participles are distributed or dispersed evenly onto paper and heated to recreate an image or text. |
Inkjet Printer
A type of non-impact printer that uses liquid ink to spray characters onto the page. |
Input
Data that is sent to the CPU for processing from an outside source such as a keyboard, CD-ROM, or modem. |
Input Device
A device used for putting data into a computer. |
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Assortment of wires connecting the CPU with external devices. These devices include all I/O connectors such as drive controllers, serial ports, parallel ports, and keyboard connectors connected to the ISA and PCI buses or adapter cards installed in the ISA and PCI bus slots. |
Input/Output (I/O) Port Address
An I/O port address is an address specific to a data pathway leading into or out of a computer or network. |
Input Signal
Manufacturer specification for the type of video input the monitor uses. The standard for modern analog monitors is the RGB Analog. This is opposed to the old TTL digital standard. |
Insulator
Any nonconductor of electricity. |
Integrated Circuit
A device consisting of many interconnected transistors or resistors contained on a single chip of silicon crystal or other semiconductor material. Integrated circuits are classified by the number of elements they contain. |
Integrated Circuit Board
Thin, rectangular plate, usually made of silicon, on which chips and other electronic components are placed. There are several of these boards in a computer. They are often called cards or adapters. Examples of integrated circuit boards include the motherboard and expansion cards. |
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A type of drive interfaced ratified in 1989 and called the ATA standard. The standard gave specifications for the integration of the old ST-506 disk controller circuitry onto the hard drive. This standard was superceded by 1995's ATA-2 standard. |
Integrated I/O Connector
Connector for external devices to the motherboard. It is integrated into the system by means of a PCI slot. |
Integrated Peripherals
Devices that typically include the onboard floppy and hard drive controllers, USB controller, serial ports, and parallel port. |
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Special chip that arbitrates between contending devices on the bus. It gives the device that is capable of bus mastering full control of the bus and temporarily suppresses all other bus traffic except if it is high priority. |
Intel
A US microelectronics manufacturer founded in 1968 by Gordon Moore and Robert Noyce to design, manufacture, and market semiconductor computer memory to replace magnetic core memory. In 1971, Intel introduced the world's first microprocessor, the Intel 4004. Other products introduced by the company include the Intel 8080, Intel 8086, Intel 80186, Intel 80286, Intel 80386, Intel 486 and Pentium microprocessor families as well as many other integrated circuits and personal computer networking and communications products. |
Intel 4004
The first microprocessor. It was released in 1971 and contained 2300 transistors. The Intel 4004 was originally intended for use in a calculator. |
Int 13h
The original method of accessing the hard drive through the BIOS. Int 13h was designed to support drive up to 8GB.
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Int 13h Extensions
The modern hard drive access method which eliminates the 8GB limit. Int 13h Extensions requires BIOS, operating system, and software support to function. |
Interface
Something that connects two separate entities, programs, devices, or programs to devices. Types of interfaces include devices, components, or programs.
The actual physical pin-out connector of the drive to the computer system expansion bus. Either IDE or SCSI, this interface is connected to the appropriate controller by a 40 or 50-pin flat ribbon cable. |
Interlaced
A scanning mode in which the scanning beam goes across the screen from top to bottom
but alternates between every other line, requiring two passes across the screen. The first scan is for even lines, the second for odd. This allows monitors to support higher resolutions at lower frequencies, but leaves undesirable flicker. |
Interleave
A process for increasing memory speed that takes data bits and alternates them between two or more memory pages or devices. |
Internal I/O Connector
A type of device on the motherboard that serves as an interface between the I/O bus on the motherboard and an external component or device such as the floppy disk drive controller and hard drive controllers. |
Internal Register
An internal CPU bus for data that is composed of data paths and storage units. |
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Company known as IBM. It started in 1911 as a producer of punch card tabulating machines. During the 1960s and 1970s, IBM dominated in the fields of mainframe and minicomputers. In 1981, the company introduced a personal computer called the IBM PC which became the industry standard. |
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The international organization that sets of modulation standards which govern the basic rate or speed of modem communications. Formerly called the Consultative Committee on International Telephone and Telegraph (CCITT). |
Internet
A global communications network that connects smaller networks and online services throughout the world. |
Internet Explorer
Microsoft's flagship Internet Web browser. |
Internet Service Provider
A company that provides access to the Internet for a monthly fee. The ISP provides an access phone number, username, and password for a modem-equipped user to logon to the Internet and use Wide World Web, file transfer, news, and e-mail services. |
Interrupt Request Channel
Term used for hardware interrupts or IRQs. An IRQ carries signals generated by a hardware device to tell the CPU that a request needs to be executed. |
I/O Base Address
Beginning number in a range of numbers that comprise a device’s address in memory. |
I/O Bus
A bus for data that is composed of data paths and storage units. It can either be internal or external.
See . |
I/O Port Address
System resource used by every device. It represents a memory location that is set aside for use by a device to exchange information between itself and other devices and between itself and the operating system.’ |
io.sys
One of the three MS-DOS operating system files that the MS-DOS bootstrap loader searches for in the root directory of the boot disk and loads into memory. |
Ion
An atom or molecule that has gained or lost electrons and thus has a net positive or negative charge. Atomic particle. In general, negative ions have an excess of electrons, and positive ions lack electrons. |
Ionizer
Electrical device used to generate ions into the air. It helps to prevent static buildup and ESD. |
IrDA
Abbreviation for Infrared Data Association. This is a group of device manufacturers. They developed a standard for sending data by means of infrared light waves. |
IRQ
Another term used for a hardware interrupt or and interrupt request channel. |
IRQ address
Address of a hardware interrupt on a PC. |
ISA (Industry Standard Architecture)
ISA "cards" attach to a computer's motherboard to expand the computer's functions. A sound card, for example, allows a computer to produce sound effects, music, and voices. |
ISA Bus Card
Type of bus used in the IBM PC/XT and PC/AT. The letters ISA are an abbreviation for industry standard architecture. The successor of this type of bus was the PCI local bus. |
ISA Expansion Slot
Industry standard architecture expansion slot on the motherboard that connects to the I/O bus. |
ISDN
Short for integrated services digital network, an international communications standard for sending voice, video, and data over digital telephone lines. ISDN requires special metal wires and runs at up to 64kbs transfer rates. |
Isopropyl Alcohol
C3H8O. Type of alcohol used as a solvent. |
ISP
Internet Service Provider. See Internet Service Provider. |
ISP Chip
Integrated system peripheral chip. See |
ITU
International Telecommunications Union. See |
Infinite
Extending indefinitely. Endless. Immeasurably or inconceivably great or extensive.
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J
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Inventor of the modern computer along with Clifford Berry. |
Joule
A unit used to measure energy that is equal to one watt of power per second. One calorie is roughly four joules. |
Joystick
Hardware input device that is used to control on-screen movement. It is usually used in game applications to control the movement of some object such as an animated character.
The most common type of game adapter used to enter movement data into the system much like an airplane joystick. |
Jump Drive
This drive is small, compact, and provides a revolutionary way to store, transfer and carry data without the need for software installation or cables to plug in. |
Jumper
A bridge or small plug used to close an electrical circuit. It consists of a plastic plug that fits over a pair of pins. They are used to configure the circuits on a motherboard.
An on/off switch that is used to change hardware configurations so that circuits can be open or closed. It consists of wires and a small piece of metal that can be used to connect or close circuits. Typically, jumpers are found on devices such as sound cards, graphics cards, modem cards, and motherboards.
A bridge that closes an electrical circuit. Usually, jumpers consist of plastic plugs that fit on top of a pair of protruding pins. They are used to configure the motherboard. |
Jumper Cap
Another term for bridge. The small plastic device used to close the circuit intersection on the motherboard.
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K
Katmai New Instructions
See SSE (Streaming SIMD Extensions) |
Kernel
The part of an operating system closest to the computer. A kernel may activate computer hardware directly or communicate with another software layer that drives the hardware. |
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A grid array of key switches monitored by an onboard processor which collectively form the keyboard. The onboard keyboard processor monitors the coordinates on this matrix to interpret input. |
Keyboard
Hardware input device that allows the user to type or enter commands into the computer. Based on the typewriter keyboard, a typical PC keyboard contains special keys that are used with computer programs. |
Keyboard Interface
A special serial port, unlike the standard com ports, which handles serial communications between the keyboard and the motherboard. The interface can be of two different types: standard AT/DIN or mini-DIN. |
Keylock
Security device that when locked with a key, locks all access to system input devices. |
KHz (Kilohertz)
The frequency of a radio wave measured in thousands of cycles per second. 1 kHz is equal to 1,000 Hertz. |
Kilobyte
1,000 bytes. A measure of computer memory space. |
L
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A small, fast cache memory inside or close to the CPU chip. It is also sometimes referred to as the primary cache. |
L2 Cache
See level two cache. |
Land
These are the flat surfaces in between the pits on the surface of a compact disc. The patterns of pits and lands represent data stored on the reflective surface of every CD-ROM disk. When data is being read, light from the laser is bounced off the pits and lands located on the underside of the disk. Because the lands reflect more light, they are read by the CD-ROM drive as 1s. |
LAN
Acronym for Local Area Network. |
LAPM
Link Access Procedure for Modems. See . |
Laptops
A small portable, personal computer, designed for traveling, that uses batteries or AC power. A laptop computer has a flat screen and usually weighs less than ten pounds. |
Large Drive Connectors
Larger of the 4 pin power supply connectors. These power supply leads connect to the hard disk drive or the older technology 5.25" floppy disk drives and use 12 volt motors to operate. |
Laser Printer
A type of non-impact printer that uses a laser to draw an image on an electrically charged drum which is transferred to electrically charged paper using toner. |
Laser Scanning Assembly
The part of the print engine in a laser printer which transcribes the array of dots created by the printer controller into a printable image on the photoreceptor drum. This uses a laser beam with a rotating mirror and a lens emit and focus light pulses onto the drum. |
Layered Circuit Board
Circuit board that consists of several rectangular plates that are layered one on top of the other. Included on it are chips and electronic components. |
LBA
Logical Block Addressing. See |
LCD (liquid crystal display)
Monitor type that uses a polarized, molecular structure liquid, held between two see-through electrodes, as its display medium. |
LED
Light-emitting diode. A type of device that lights up when electrical current passes through it. Depending on the material used, the color can be visible or infrared. Visible LEDs are used as indicator lights on all sorts of electronic devices. |
Legacy
Describe older versions of still current devices. An ATA-1 is an ATA family legacy drive. |
Level Two Cache
Cache memory that is external to the microprocessor. It is also called the secondary cache of the L2 cache. Generally, L2 cache is on a separate chip from the CPU, however the Pentium Pro has an internal L2 cache. |
Li-Ion
Current portable computer battery industry standard. Li-Ion batteries can be used only in systems designed for them. |
Light Pen
This light sensitive pointing device is similar to a mouse and used to select, modify or manipulate information or data on a computer screen by touching the screen directly with the pen. |
Line Conditioner
Term sometimes used to describe equipment that provides some type of filtering or regulation to an AC power source. A line conditioner can be any of the following devices: surge suppressor, ferroresonant transformer, AC filter. Or tap changing regulator. |
Line Interactive UPS
Type of UPS that is always connected to the output. In a line interactive UPS, the inverter works in parallel with conditioned input AC power to supply power to the load, and only handles the full load power when the AC input power fails. |
Line Noise
Undesirable communications channel signals that occur on an electrical circuit. |
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An error correction standard established by the ITU called V.42 which defines how parity-checking methods are to be used in the modern modem transmission. |
Linux
A UNIX-like operating system designed to provide PC users with a low cost or free operating system. |
Lithium ION Batteries
Current portable computer battery industry standard. Li-Ion batteries can be used only in systems designed for them. |
Lithium-Ion polymer
Newest development in lithium-based rechargeable batteries. Provides the advantage of small size (1mm) and is expected to become the next standard in portable computer battery. |
Liquid Cooling
Functioning much like a radiator, this system uses a flexible tube to circulate a water-based solution through a heat sink that is attached to the processor inside the computer. |
Load Resistor
Device that maintains the power flow at a predetermined minimum operating limit in the power supply. It regulates the power flow for the power supply’s converter. |
Load Runtime
Amount of time a UPS can supply the system with electricity from battery power. |
Load Setup Defaults
BIOS setup section that provides a choice of whether to reset the BIOS setup screens to default settings. |
Loading Mechanism
The method of loading the CD disk into the CD-ROM reader drive. The method can be a tray loader mechanism or a caddy mechanism. |
Local Area Network (LAN)
A data network designed to cover a relatively small geographic area. LANs are designed to connect workstations, peripheral devices, terminals, and other devices in a single building or limited geographical area. |
Local Loop
The local analog phone line segment of the telephone network from the nearest PSTN switch. These are the telephone lines between homes or businesses and the telephone company's central switches. |
Lockup
Computer condition in which applications and hardware are stuck or incapable of proceeding without help. Lockup is different from crashing. If the system has crashed, it has become totally non-functioning. If the system is locked up, it is trying to do something but cannot make progress; it may be capable of doing a few things, but not be fully operational. |
Logarithm
One of a set of numbers devised in such a way to assist in doing calculations by using addition and subtraction, in place of multiplication and division. |
Logic Board
A circuit board with soldered on or socketed silicon chips to control a computer component. |
Logic Chip
Another term used with chip. A silicon chip or integrated circuit containing embedded instructions or logic. These types of chips control and coordinate functions on devices with logic boards. |
Logic Chip Set
Another term used for chip set. A group of silicon chips that includes the embedded instructions or logic to control and coordinate components and communications on a circuit board. The term is usually used to refer to the main group of chips which functions on the motherboard. |
Logic Chip Set
Another term used for chip set. A group of silicon chips that includes the embedded instructions or logic to control and coordinate components and communications on a circuit board. The term is usually used to refer to the main group of chips which functions on the motherboard. |
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If used by operating systems as well as by the drive on the hardware side of the BIOS, LBA can be a more efficient way to address hard drives than the standard CHS (Cylinder, Head, Sector) method of addressing. LBA is a way of addressing hard drives by assigning numbers sequentially to each sector on the drive, starting from 0 for the first sector. As part of this process, the BIOS provides sector translation which allows the system to see hard drives with a larger size than 528mb. |
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A logical number given to a device attached to a SCSI Physical Unit and not directly on the SCSI bus. Technically, up to eight LUNs can be attached to one Physical Unit Number, although in reality, a single LUN is built-in part of a Physical Unit. So, the hard drive circuitry built-in to the SCSI adapter on the hard drive has Physical Unit Number, while the associated controller and drive themselves have a Logical Unit Number. |
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Device that enables testing of the circuit or leads. It does this by sending signals out and recognizing if the correct input is received back. |
Lotus 1-2-3
Spreadsheet application for MS-DOS from Lotus Development Corporation. It can be programmed using "macros" and comes with a separate program to produce graphs and charts. |
Low-Level Formatted
Creating tracks and sectors on a hard drive's blank magnetic platters. Low-level formatting is usually performed by the manufacturer before shipping.
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Low Profile
Another term used for a Slimline form factor. Hard Drive LED. Another term for hard drive light. |
Low Radiation
Another manufacturer specification indicating its compliance with international standards for Very Low Frequency (VLF), and Extremely Low Frequency (ELF) magnetic emissions. These are potentially harmful types of long term radiation exposure for which the standards are designed to minimize. |
Low Voltage Differential (LVD)
A signaling method used in SCSI. LVD uses two pins to send signals, each are mirror images of the other. This allows the signal to travel farther and resist interference. LVD devices are generally compatible with SE busses, but the LVD device loses its special abilities when combined with them. LVD can extend to 12 meters (13.1 yards). |
Low Voltage Differential Termination
Special terminators used on LVD devices that need to be run in LVD mode. |
LPT Port
Another name for parallel port. Usually, this term is used with a number, such as LPT1 or LPT2. When used in this way, the term is an internal address that is read by other devices attached to the system. |
LUN
Logical Unit Number. See |
Lynx
A standard for a high speed external bus that can connect up to 36 devices with 400Mbit/second transfer rates.
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M
Mac OS
Mac OS is short for the Macintosh operating system. Although formally renamed System 7 operating system in 1997, the term Mac OS is still synonymous with Macintosh operating systems. |
Magnetic Media Disk
One of three parts of a floppy diskette. A round plastic disk coated with a magnetic substance that is encoded with data by the floppy diskette drive |
Mail Server
A network computer that stores incoming email for safekeeping, until it can be distributed to the appropriate users. |
Main Board
Another name for the motherboard. |
Main System Bus
Another term used for the input/output bus. |
Mainframe
A large computer designed for high-level computational tasks. Mainframes are typically shared by other PCs that are connected together. |
Maintenance Wizard
A Microsoft graphical, step-by-step instructional guide that assists users in accomplishing specific tasks. |
Mass Storage
Generic term for devices that store large amounts of data. |
Master
Integrated Device Electronics device in first position device sequence. Subsequent devices are slaves. |
Master Boot Code
The initial boot program located in the master boot record that the BIOS loads and executes to start the boot process. This program seeks the boot partition with the bootstrap loader and transfers control to the loader for starting the operating system. |
Master Boot Record
Another term for boot sector. See . |
Master Partition Table
This is a table located in the master boot record that contains the descriptions of the partitions that are contained on the hard disk. |
Mass Storage
Generic term for devices that store large amounts of data. |
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See |
Math Coprocessor
Performs math operations for the CPU. Also called the numeric coprocessor or floating-point coprocessor. |
Mbps
Megabits Per Second. One million bits per second. A measurement of data transmission speed. |
MDA
Monochrome Display Adapter. The first display standard introduced in 1981 by IBM Corporation. This was a character-only video display with no graphics capability. It existed along side the CGA and later EGA standards as a budget alternative, but also became obsolete upon the introduction of VGA in 1987. |
Mean Time Between Failure
The failure rate of a power supply established by the actual operation or calculation from know standards. It is expressed in hours. |
Media
Generic term for the actual storage container in a floppy or hard drive. |
Media Access Control (MAC) address
A unique address used to give each network node a unique identity. |
Media-Access Hole
The cut away at the top of the plastic jacket on a floppy diskette that exposes the magnetic media disk for read/write operations. Another term for read/write window. |
Media Sensor
A sensor in higher density floppy disk drives which detects the capacity of the floppy disk inserted and switches the drive into the proper read/write mode. |
Megabyte
When used to describe data storage, 1 megabyte is equal to 1,048,576 bytes and is abbreviated as M or MB. When used to describe data transfer rates, 1 megabyte is equal to 1,000,000 bytes. |
Megahertz (MHz)
One MHz equals one million cycles per second. It is most commonly used to measure transmission speeds of electronic devices. |
Membrane Keyboard
A variant of the rubber dome keyboard design where the key caps are integrated into a continuous sheet that sits directly atop the rubber dome sheet. |
Memory Address
Reserved space in the upper memory area used by a hardware device for its BIOS.
Each device has a reserved range of system memory to load its device driver. The memory address is kept in a table that the CPU can check to find where to go to execute software instructions for that device when requested by a program or another device |
Memory Bus
Assortment of wires through which data is transmitted between the CPU and the main memory or RAM. |
Memory Effect
Common with nickel-based rechargeable batteries: a battery loses its ability to fully recharge if it has been charged before it is fully drained. |
Memory-Mapped I/O
Process during which a device will leave data in an area of memory reserved for it where another device in the communication exchange will know to pick it up. |
Memory Module
A small circuit board with RAM integrated circuits or die on one or both sides and a single row of pins along one long edge. Typically, one SIMM can hold 8, 16, or 32MB. |
Memory Stack
When a device sends an interrupt, this is the place where the CPU register contents are sent when the software routine halts the CPU. |
Mesh
A LAN topology where every computer is connected to every other computer on the network. |
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Type of surge suppressor that operates by means of voltage clamping. It is capable of absorbing large currents without damage. Also called a MOV. |
Metal Sheath
A sliding shutter that protects the media-access hole on a floppy diskette when not in the drive. |
Metropolitan Area Networks (MAN)
Uses WAN technology to interconnect LANs within a geographical region, generally a city. |
Mezzanine Design
Term used to describe the architecture of the PCI bus because it adds another layer to the traditional bus configuration. |
MHz
Abbreviation for megahertz. One MHz equals one million cycles per second. It is most commonly used to measure transmission speeds of electronic devices. |
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The company that made the Altair 8800 and Altair 9000 microcomputer kits. |
Microchip
Same as microprocessor, or the computer's central processing unit (CPU). The microprocessor can be thought of as your computer's brain. |
MicroDIMM
Among the smallest memory modules available, these chips are commonly used in ultra-slim or sub-notebook computers and other small form devices. |
Microphone
A device that changes sound waves into analog signals. A microphone is used to "input" sounds into a computer. |
Microprocessor
The computer's Central Processing Unit (CPU) is its microprocessor. A CPU is a microchip about the size of a thumbnail that acts as a computer's brain. Common examples of CPUs include Intel's Pentium and 486DX. |
Microsoft
Company founded in 1975 by Bill Gates and Paul Allen. The company’s first product was a version of BASIC for the Altair computer. In 1980 Microsoft was chosen by IBM to supply the operating system for the IBM PC. Today, Microsoft’s software products include MS-DOS, Microsoft Windows, and Windows NT. |
Microsoft Word
A popular word processing application that is part of the Microsoft Office suite. Early versions of Word were originally text-based and ran under MS-DOS. Later, versions using a graphical user interface were developed to run with Windows. |
MIDI
Musical Instrument Digital Interface. A hardware specification that makes it possible to connect synthesizers and other electronic musical equipment to a computer. |
MIDI-IN
Delivers the data to an instrument. |
MIDI-OUT
Sends the data out from an instrument that it originally came from. |
MIDI-Thru
Sends an exact copy of the data coming into the MIDI-In and passes it on to another instrument or device. |
Mid-Tower
Medium size of the Tower form factors. |
MID
Extension identification for MIDI (Musical Instrument Digital Interface) files. |
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Motherboard mouse and keyboard connector. The initials DIN stand for Deutsche Industry Norm. Translated into English, this means the German Industrial Norm. It is a committee that sets German dimensional standards. On PS/2 systems, this type of connector is a 6-pin connector. |
Mini-Tower
Smallest of the Tower form factors. |
Minuteman Missiles
Term used to describe ballistic missiles with range capabilities from about 3,000 to 8,000 nautical miles. |
Mirroring
Method of fault-tolerance in which a backup disk writes all data to the primary disk, ensuring the data will be recoverable if the primary disk drive fails. |
MITS
See . |
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Electronic device used for computer communications via telephone lines. It allows data transfer between one computer and another, allows one PC to share data with another that is some distance away, or allows a PC to connect to a bulletin board service or another online service.
Acronym for Modulator/Demodulator. A modem is a device that enables a computer to transmit digital data over analog telephone lines through modulation and demodulation. |
Modem Port
A serial port used to connect an external modem to a personal computer. |
Modulation
Converting digital data carried over telephone lines to analog data by varying the frequency of an electronic wave. |
Modular
That which is constructed with standardized units or dimensions for flexibility and variety in use. |
Modulator/Demodulator
Functional description for a modem. See |
Monitor
The monitor is a cathode ray tube device that allows the user to see what the computer is doing, just like a TV screen. Monitors display the information the computer is processing in real time, or as it is happening.
Another term for video display monitor, display monitor, or video monitor. |
Motherboard
Main computer circuit board that holds the processor and the main memory as well as other essential computer elements. The motherboard is the attachment point for useful additional computer boards like video and sound cards. |
Motherboard Connectors
A series of power supply leads that connect to a motherboard inside a system unit. The number of power supply leads varies, depending on the type of motherboard and power supply used. |
Motherboard Ground Screw
A special type of hexagonal screw used to ground the motherboard to the mounting plate at specific points |
Motherboard Manual
Booklet containing specifications, instructions, and diagrams for the motherboards, the devices attached to them, and their configuration. Each motherboard model and form factor has a corresponding manual. |
Motherboard Mounting Pan
See . |
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Term used for the motherboard mounting pan. The part of a computer case that provides the attachment surface for the motherboard. |
Mounting Bay
A recess or indentation in the front bezel or face plate of the case for inserting a drive into an drive bracket. |
Mounting Chassis
The outer bracket of the hard drive that contains the head disk assembly, and has the mounting screw holes to secure the drive into the drive brackets. |
Mounting Points
Holes in the motherboard that are used to secure it to the motherboard mounting plate by means of ground screws and stand-offs. |
Mouse
Hardware input device that allows the user to point to and select items on-screen. It is used primarily with graphical user interface (GUI) programs to select icons and menu commands. It is also used with most drawing and paint programs. |
MOV
See |
MP3
File extension for MPEG
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MPC Compliance
Measure of whether the particular CD-ROM drive meets the minimum specifications recommended for multi-media systems by the Multimedia PC Marketing. The MPC Council recommends minimum average access speed requirement for MPC compatible CD-ROMs for different speed drives: i.e., 2x speed CD-ROMs must be 400ms, 4x speed CD-ROMs must be 200ms, etc. |
MPC (Multimedia PC)
Shorthand for the Multimedia PC Working Group, of the Software Publishers Association. MPC sets industry standards for multimedia PCs. |
MPC1
The original multimedia PC standard set by the Multimedia PC Working Group (MPC). |
MPC2
Multimedia PC Working Group’s second standard level of performance specifications. |
MPC3
Multimedia working group’s third standard level of performance specifications. |
MPEG
Standards developed by the Moving Picture Experts Group. They are for digital video and digital audio compression.
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MPEG-1, layer 3
File extension that contains compressed music and video data. |
MPEG Codec
Standards developed by the Moving Picture Experts Group. They are for digital video and digital audio compression. |
MPRII
A defacto international standard for low radiation emissions developed for monitors by the Swedish regulatory agency, SWEDAC. This is now a compliance standard for many countries for manufacturers to sell their monitors. |
MSDS (Material Safety Data Sheet)
This standard reference documentation is meant to improve an employee’s safety and reduce the risk associated with meeting stringent compliance standards by such organizations as OSHA. |
MS-DOS
The Microsoft Disk Operating System. The first operating system developed and licensed for the IBM compatible computer system. The last released version was version 6.22 in 1994. |
msdos.sys
One of the three MS-DOS operating system files that the MS-DOS bootstrap loader searches for in the root directory of the boot disk and loads into memory. |
MTBF
See Mean Time Between Failure. |
Multi-Frequency Rate
The ability of a monitor to support many different horizontal and vertical scan frequencies, and therefore many resolutions. |
Multi-monitor support
Technology that permits users to simultaneously operate as many as nine monitors to run tests or perform other diagnostic operations. |
Multimedia
In computer context, an integrated method of presenting text, graphics, video, and sound. |
Multimedia PC (MPC)
Shorthand for the Multimedia PC Working Group, of the Software Publishers Association. This association sets industry standards for multimedia PCs.
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Multiprogramming
Also called multitasking, the capability of two or more programs running on a single computer at one time. |
Multi-station Access Unit (MAU)
Centralized connection point for token ring networks. |
Multi-Tasking
The ability of the operating system to run several concurrent operating tasks as opposed to one at a time.
The ability to execute more than one task at the same time. A task is a program or software module. |
Multiword
A DMA mode that allows multiple 16 bit blocks to be transferred at once, reducing the number of interrupt requests that must be generated. |
Multi-Word DMA Mode 2
A direct memory access mode drive transfer operation used by some advanced ATA-2 hard drives and incorporated into Ultra DMA hard drives.
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N
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One billionth of a second. |
Near Letter Quality
A print quality mode for dot matrix printers intermediate between draft and letter quality. |
Negotiation
Used metaphorically, the process humans do to work out agreeable situations is similar to the process modems use to arrive at a common modulation standard. |
Netburst Technology
Increased advances in multimedia begun with Pentium IV |
Netscape Nevigator
Netscape's flagship Internet Web browser. |
Network Card
Sometimes called a network interface card. Circuit board that can be added to the motherboard. It provides network communication capabilities to and from a computer system. |
Network Interface Card (NIC)
A network interface card is a printed circuit board that plugs into both client and server computers to regulate the data exchange. |
Networking Operating System
An operating system on the server in a LAN that coordinates the activities of computers and other devices attached to the network |
Neutral Wire
In a circuit, the wire that is connected to an earth ground at the power plant and at the transformer. |
Nickel Cadmium (NiCad)Batteries
NiCad is a trademark of SAFT America, Inc. for nickel cadmium products. The word NiCad is also used as a generic term to describe nickel cadmium batteries. |
Nickel Metal Hydride (NiMH)Batteries
Rechargeable, non-toxic battery offering better performance than NiCad batteries. |
Nine (9)-Pin Serial Port
Type of serial port employing nine pins or contacts |
NLX motherboard
New in 1997, NLX supports NetPCs and other space-saving systems. NLX uses a riser card for expansion boards and supports the Accelerated Graphics Port. |
NMI
See . |
Node
A device connected to the network that can communicate with other network devices. |
Noise
Undesirable communications signals. See . |
Non-Impact Printer
The class of printers in which nothing in the printer actually impacts the paper to form characters. This class includes laser printers and inkjet printers. |
Nonconductor
Sometimes called an "insulator," a nonconductor is any material that conducts electricity poorly or does not conduct electricity at all. |
Nonimpact Printer
Laser and ink-jet printers are nonimpact printers because they do not physically strike paper. |
Noninterlaced
A scanning mode in which the scanning beam goes across the screen from top to bottom continuously over every line. This is the standard scanning mode for quality monitors. |
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A signal informing a program that an event has occurred. When a program receives an interrupt signal, it takes a specified action. |
Non-User Definable
Informational box screens that give information on the BIOS configuration of the system which do not offer configurable choices for the use. Examples are the autodetect video fields and keyboard fields of the main BIOS setup screen. |
Non-Volatile
Type of memory that retains its contents when the power is turned off. Read-only memory (ROM) is non-volatile. |
Notebooks
A portable computer that weighs from approximately five to seven pounds. |
NTFS
Short for New Technology File System. A file system introduced by Microsoft with the Windows NT operating system in 1993. |
NS
Abbreviation for nanosecond. A nanosecond is a time measured computing speed, specifically the speed at which electrical signals travel through circuits within the computer. A NS equals .000000001 seconds. |
O
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A place or building for scientific observations of the heavenly bodies using special instruments. |
Octal Number
Base 8 numbering system using the digits 0-7. |
Octet
An exactly 8-bit piece of data. |
Offline
Backup power device that operates off line. See Standby Power Supply |
Offline UPS
Type of UPS that operates off line. See . |
Off-The-Sheft
Software packaged and available for sale in ordinary computer stores. |
One Hundred One (101)-Key Enhanced Keyboard
The defacto standard layout for computer systems originally introduced by the IBM Corporation in 1986 and since copied by all clone manufacturers. |
One Hundred Four (104)-Key Enhanced Keyboard
A modified version of the 101-key enhanced keyboard with three extra command keys added to support the Microsoft Windows 95 and NT operating systems. This is rapidly becoming another defacto standard to challenge the 101-key dominance. |
Online UPS
Type of UPS that operates online. |
Operating System
A software that manages the allocation of hardware resources such as memory, disk space, CPU time, and peripherals. Examples of operating systems for PCs are MS-DOS, PC-DOS, OS/2, and UNIX. |
Operating System 2
An operating system jointly developed and introduced by Microsoft and IBM in 1987. Intended as a replacement for DOS, Microsoft and IBM followed different development paths after the initial release. IBM retained development rights and continued development through version 4 in 1997. |
Operating System Boot Disk
Disk used to initialize or start the operating system software. |
OS (Operating System)
See Operating System. |
OS/2 (Operating System 2)
See Operating System 2. |
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A change in the electrical signal that occurs periodically.
See , , and . |
Oscillator Circuit
A high-speed switch that rapidly moves back and forth between the different voltage outputs. |
OSI
A network standard for worldwide communication systems. |
Outlet Tester
A device which tests for proper conductor connections of electrical outlets. Normally lights will indicate a proper or improper wiring of the outlet. |
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The processed data from the CPU that is displayed on the monitor is output. Other forms of output include information sent to a printer or fax/modem. The output is one of the primary functions of a system. |
Output Device
Any internal or peripheral device attached to the system unit either internal or peripheral that completes the task the CPU intends it to do. See |
Over Clock
Over clock is a manipulation to speed up the computer beyond the manufacturer’s specifications to produce a faster running computer. |
Overload Protection
Protection provided on all outputs against short circuits. |
Overvoltage Protection
A feature of the power supply that shuts down the supply or clamps down on the output when its voltage exceeds a preset limit. |
Oxide
Any element, particularly a metal, that has formed a compound with oxygen. For example what is commonly referred to as rust is iron oxide. |
P
P cable
68-pin cable, mandated in SCSI-3, to be used with 68-pin connectors for 16-bit buses. |
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A language for describing the layout and contents of a printed page. These are what the computer application software uses to send commands to the printer for the desired results. There are two defacto standards for these languages: PCL and Postscript. |
Page Format
The layout of a page which includes the fonts, spacing, paper size, margins, text layout and graphics. |
Page Printer
Another term for laser printer. See Laser Printer. |
Pages Per Minute
A measure of laser printer printing speed. How many pages per minutes the printer can output at a given resolution. |
Paper Path
The channel through which the paper feeds and is transported through a printer. |
Paper Transport Mechanism
The electro-mechanical means by which the paper is moved through the paper path in a printer. |
Paradigm
A pattern, model, or example. |
Parallel Communication
Parallel communication occurs over a computer's parallel port. Eight data bits continuously flow parallel to each other over the printer cable. |
Parallel Port
A parallel interface for connecting an external device. These types of interfaces are capable of transmitting more than one bit of data at a time. Printers usually are connected to the computer using parallel ports.
Type of plug-in receptacle located on the motherboard that can move 8 bits of data at a time. Because of this, parallel ports are faster than serial ports. |
Parallel Processor
An architecture within a personal computer that can perform multiple operations simultaneously. |
Parity-Checking
Technique used to detect errors. It uses character bit patterns that are forced into parity. This is accomplished by the addition of a one or zero bit to each byte, as the byte is transmitted; at the other end of the transmission, the receiving device verifies the parity and the accuracy of the transmission. |
Parity Error
An error discovered by the inclusion of a parity bit. |
Pascal
French mathematician Blaise Pascal who invented the first recorded calculation machine,the Pascaline. |
Pascaline
A calculating machine developed in 1642 by French mathematician Blaise Pascal. |
Passive termination
SCSI termination that uses resistors to dissipate voltage to termination level. Passive termination is effective for shorter distances. |
Patent
A written document securing to an inventor for a term of years the exclusive right to make, use, or sell an invention. |
Patch
Either a patch can be either a temporary solution to a technical problem, or a sample of an instrumental sound sometimes found on a music synthesizer. |
PC Card
A credit-card-sized PC card that attaches modems, network adapters, sound cards, and other devices to portable computers. PC Cards a built to conform to PCMCIA (Personal Computer Memory Card International Association) standards. |
PCI (Peripheral Component Interconnect)
A high-speed bus created by Intel for use between a CPU and peripheral devices. PCI buses offers automatic Plug and Play capability. PCI buses are the successor to ISA buses. |
PCI bus cards
An Intel-developed ISA bus successor that provides local bus performance plus processor independence and multiple processor capabilities. PCI supports a new set of controller chips in addition to plug-and-play. |
PCI IDE
Component Interconnect and Integrated Drive Electronics, or PCI IDE, is a bus used for communication between peripherals and PCs. IDE is the hardware that connects peripherals to a PC. |
PCL
Printer Control Language. See Printer Control Language. |
PCMCIA
Personal Computer Memory Card International Association (PCMCIA), is an international standards body and trade association. PCMCIA was created in 1989 to establish standards for connecting peripheral devices to portable computers. It is now consists of more than 500 companies. |
PC/XT
The first form factor developed that became an industry wide standard. It was developed by IBM. |
PDA
A personal digital assistant is a tiny, handheld computer that functions as an organizer for personal information. |
PDL
Page Description Language. See Page Description Language. |
Perforated
To make a hole or holes through an object by punching or piercing. |
Peripheral
Any part of a computer's hardware other than the CPU or working memory. Some examples of peripherals include disks, keyboards, monitors, mice, printers, scanners, tape drives, microphones, speakers, and cameras. |
Peripheral Component Interconnect (PCI)
A high-speed bus created by Intel for use between a CPU and peripheral devices. PCI buses offers automatic Plug and Play capability. PCI buses are the successor to ISA buses.
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Permanent Virtual Circuit (PVC)
See . |
Personal Computer Memory Card International Association
Standards and trade organization begun in 1989 to establish peripheral device attachment standards for portable computers. |
Pentium
Intel’s fifth 80x86 central processing unit. Follows the 486 processor and begins Intel’s current "fast" central processing unit line. |
Pentium II
Intel’s follow-up to its initial Pentium series. Pentium II is characterized by built-in multimedia extensions and easier upgrading. Pentium II’s easier upgrading is a result of its new motherboard "Slot 1" mounting. |
Photodetector
The light-sensitive receptor in a CD-ROM drive that senses fluctuations in the light beam reflected to it from the disk surface. The photodetector converts light beams into electrical impulses that are readable by a computer. |
Photosensitive Drum
Laser printer component that develops an electrical charge when exposed to light. |
Physical Unit Number
A term used to describe a device connected directly to the SCSI bus. The Physical Unit Number is the same as the SCSI ID. See . |
Pinout
Text, a diagram, or a table that describes the purpose of each pin in a chip or connector or each wire in a cable. |
PIO (Programmed Input/Output)
PIO is a data transfer method that uses two devices and the CPU as part of the data path. |
Pit
These are indentations burned into the smooth surface of the compact disc, leaving flat surfaces in between. The patterns of pits and lands represent data stored on the reflective surface of every CD-ROM disk. When data is being read, light from the laser is bounced off the pits and lands located on the underside of the disk. Because the pits reflect less light, they are read by the CD-ROM drive as 0s. |
Pixel
Short for picture element, this is the smallest element of a video image. It is composed of three primary phosphor color dots. |
Pixel Rate
The speed at which the RAMDAC chip can draw the pixels. This is commonly expressed in megahertz (MHz). |
Plain Old Telephone Service (POTS)
A term used to refer to traditional telephone communication lines. |
Planar
In computer graphics, lying within a plane; anything that is two-dimensional in quality. |
Plastic Jacket
The hard outer shell that protects the magnetic media disk in a floppy diskette. |
Plenum
Within a building, this is the crawl space (ceiling or false floor) that contains electrical, network and telephone wires. |
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Term used to refer to the ability of a computer system to automatically configure expansion boards and other devices. It is designed to eliminate setting DIP switches, jumpers, and other configuration elements. |
PnP
Abbreviation for plug and play. See . |
PnP/PCI Configuration
BIOS setup section containing the feature settings used to control the system I/O bus, IRQ and DMA allocation for ISA and PCI Plug & Play devices. |
Pocket Computer
A pocket computer is a small, handheld, calculator-sized computer. A pocket computer requires batteries and can be connected to a personal computer for data transfer. |
Point Stick
A point stick is a pointing device that resembles a pencil eraser. A point stick is located between the G, H and B keys, and is manipulated with the forefinger to manipulate the cursor. |
Port
A parallel or serial interface where data is transferred. Generally, ports are located on the back of a computer system. Usually, the signaling ports are made up of 9-pin, 25-pin, SCSI, PS/2, and the keyboard plug. |
Port Replicators
Port replicators give portable computers a copy of the ports that already exist on the unit, offering added expandability. |
Portable
Any software that can be easily moved from one type of computer to another, has a version for several hardware platforms, can be easily converted from one machine type to another, or features built-in capabilities for switching between platforms. |
Portable Computers
The phrase "portable computer" is a generic term that refers to any personal computer that can be transported |
Post Office Protocol (POP)
A standard Internet mail server that stores and holds incoming e-mail until users can log on and download their mail. |
Postscript
Adobe's page description language (PDL) used in all computer platforms. Postscript is the commercial typesetting and printing standard. |
Power Button
Button located on the front of the computer that controls electrical current to the power supply. |
Power Cord Socket
Receptacle or cavity used to connect the power supply to an external power source such as a wall outlet via some sort of electrical cord or lead. |
Power Cycle
Reboot. |
Power Good Delay
The period after the system has been turned on, during which the Power_Good signal is delayed until all voltages have stabilized. |
Power Good Signal
A +5 volt signal sent by the power supply after it has passed a series of internal self tests to the motherboard where it is received by the processor timer chip controlling the reset line to the processor. |
Power LED
Another term for power light. |
Power Light
LED or light emitting diode located on the front bezel of the case. It is plugged into a connector on the motherboard. When it is lighted, it indicates that the system is powered on. |
Power Management Setup
BIOS section containing the settings for controlling the system's optional power management for devices. |
Power On/Off Button
A computer's front case bezel button used to turn the computer on and off. |
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A lever that allows electrical current to a power supply to be turned on and off. |
Power-On Self Test
An internal diagnostic routine which checks the internal system circuits at boot-up and gives error codes for diagnosis. After the initial circuit checks, it also checks the internal components against the known list of operating devices stored in the CMOS chip. Errors are signaled by distinctive series of beeps or BIOS-specific text error messages. |
Power Supply
Box inside the computers system unit that converts AC electricity from a power outlet to the DC electricity used by the computer. The power supply box always has a fan that keeps the box and the other components from over-heating.
The device at the rear of the monitor case which plugs into a 110v wall socket to supply the power to the monitor. The average monitor power supply outputs about 100 watts. |
Power Supply Leads
Wires capable of conducting an electrical current. They connect the power supply to the computer’s internal components and drives. |
Power Supply Mount Point
Shelf or ledge upon which the power supply rests when it is attached to the chassis. |
Power Switch Connector
See . |
PPM
Pages per minute. See Pages Per Minute. |
Primary Corona Wire
Negatively charged wire evenly distributing a negative charge across the photosensitive drum. |
Print Engine
The mechanism that transcribes the array of dots created by the printer controller into a printed image. |
Print Head
The part of the printer which either physically impacts the paper surface through a ribbon to produce character dots (dot matrix), directs ink to the paper (inkjet), or burns toner onto the paper (laser). |
Printer
Hardware output device that allows data to be printed out into hard copy by the user.
An output device that produces paper printouts from computer software applications such as word processors and spreadsheets. |
Printer Control Language
A proprietary Page Description Language developed by Hewlett Packard for its inkjet and laser printers. This is a defacto standard either licensed or emulated by most other manufacturers of non-impact printers. |
Printer Connection
The port through which a printer connects to, and communicates with a printer. |
Print Consumables
Print consumables are the dyes, chemicals and inks that a printer uses to affix an image to print media. |
Printer Controller
The command center for the laser printer that reads the data output from the host computer into memory and then interprets the commands sent to it for the page format. These commands are then sent to the print engine. |
Printer Driver Software
Printer driver software communicates with the printer, controls how the printer works, and dictates what a printer does. Once a printer converts data into useable instructions, the driver software determines what a printer does with those instructions. |
Printer Interface Software
Printer interface software translates computer instructions and data into usable commands that a printer can understand. |
Print Media
Print media are the physical materials to which a printer applies images or text (e.g., sheets of paper, transparencies, labels, stickers and envelopes). |
Printing Supplies
Printer supplies consist of print media and print consumables. |
Processor Bus
Assortment of wires through which data is transmitted between the CPU and main I/O bus through the motherboard chip set. |
Programmable
An electronic device that can follow instructions. |
Programmed I/O Mode (PIO)
Common IDE data transfer form that uses the CPU's registers to hold data. PI/O mode has five levels: 0-4. Level is the fastest. |
Programming Language
One of many computer languages designed to write computer instructions and programs in which programmers express data with symbols. Some examples of programming languages include BASIC, C++, COBOL, and Pascal. |
Projector
A peripheral device that enables computer data to be displayed on a large remote screen for presentation purposes. |
Proprietary
Belonging to a company or individual. Privately owned and controlled. In the computer industry, a proprietary design, architecture, or technique is one that is owned by a company. Usually, this refers to something that is not a standard throughout the industry or is not replicated elsewhere. Usually, proprietary components are seen as a disadvantage.
In computing, any product or design that is owned by and unique to one company. The opposite of any product or design that is open, standard, or universal. |
Proprietary Standard
Specifications that are set for a specific company's product. |
PS/2 Connector
Another term for mini-DIN connector. See |
PSTN
Public Switched Telephone Network. See . |
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The international telephone system based largely on newer backbone infrastructure using digital technologies such as ATM or SONET with local interchanges to copper wires carrying analog voice data. |
Pulley
A wheel used to transmit power by means of a band, belt, cord, rope, or chain passing over its rim. |
Pulse Code Modulation Method
A way to sample and digitize sound digitally by recording successive digital sample differences. |
PUN
Physical Unit Number. See |
Punch Card
An early storage medium made of thin cardboard cards that read data as a series of punched holes. |
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PVC is a virtual circuit that is permanently available for connection with data terminal equipment. |
Q
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Signal degradation that occurs during analog-to-digital conversion across the PSTN backbones. This limits traditional modem communications to 33.6kbps. |
Queue
To line up. In computing this term refers to lining up jobs for a computer or device. Usually, jobs are executed in the same order that they were placed on the queue, however in some instances certain jobs are given higher priority. |
Qwerty
The standard English language typewriter keyboard. The letters Q, W, E, R, T, and Y are the letters on the top left, alphabetic row of the QWERTY keyboard. It was designed in 1868 by typewriter inventor, Christopher Shoals. |
R
|
A form of electromagnetic interference that creates noise on an electronic circuit. |
RAID (Redundant Array of Independent Disks)
A configuration of multiple hard drives used for fault tolerance and the optimization of data access. Also referred to as Redundant Array of Inexpensive Disks. |
RAID 5
The most common RAID type offering both striped sets and parity for both fault-tolerance and more efficient read/write capabilities. |
RAM
A group of memory chips functioning as the computer's primary workspace. |
RAM Chip
See . |
RAMDAC
See . |
RAM Socket
The motherboard connection socket used to attach the RAM circuit board. |
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Chips that contain the computer's working memory. They are used to store data and program instructions so they can be accessed by the computer's CPU. |
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Device that converts the digital images in video memory to analog signals and sends them to the video monitor. |
Rasterizing
The last pre-printing stage in a laser printer where the printer controller converts the page format to a dot array before burning it to the drum. |
Read Multiple
An ATA-2 enhanced BIOS drive command that enables the controller and drive circuitry to support multiple sector disk writes concurrently. |
Read-Only
Data that is capable of being displayed, but not changed or altered. Usually this attribute is assigned to disks, files, and directories as a way to protect or secure them from alteration. |
Read-Only Memory (ROM)
Computer memory whose data can be displayed and read, but not changed. The read-only attribute is assigned to disks, files, and directories to protect them from alteration. |
Read/Write Head
The electro-magnetic device attached to the end of the head actuator mechanism of a floppy drive that reads and writes data to a track on the floppy diskette. |
Read/Write Head Req/Ack
Short for request/acknowledgement. See . |
Read/Write Window
Another term for the media access hole of a floppy diskette. |
Recommended Resolutions
Part of the manufacturer’s Resolution specification, this is the list of display resolutions which the manufacturer recommends for a monitor model. |
Rectifier
A device for converting alternating current into direct current. An AC to DC converter. |
Refresh
A continuous change required by some devices to maintain a constant state. Some RAM chips require refreshing so their bit patterns remain charged. |
Refresh Rate
The number of times per second that the video screen display is redrawn. |
Refresh Timing
The speed at which a RAM chip is able to refresh its memory load stated in nanoseconds. |
Register
A bus for data that is composed of data paths and storage units. It can either be internal or external. |
Registered Jack-45 (RJ-45)
A type of connector used to link networked computers. |
Remote Button Switch
The remote button switch is one of two kinds of power on/off switches. It is used with the Slimline and ATX models and is mounted on the case. |
Repeater
Communications device used to extend the distance of data transmission. A repeater amplifies or regenerates a data signal. |
Req/Ack
Short for request/acknowledgement. See |
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The method that a SCSI host adapter uses to negotiate an asynchronous data transfer with a SCSI device on the bus. For each data transfer request, the host adapter sends a request to the device, and the device controller responds with an acknowledgement. |
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Signals sent between the modem and host system to manage the rate of data flow. See |
Reset Button
A button pressed to activate the reset line that sends a message to the CPU to reboot the system. |
Reset Configuration Data
Sector Translation; A method used with SCSI and EIDE disk drives to translate the cylinders, heads and sector specifications of the drive into numbers that can be used by enhanced BIOS. This allows the BIOS to acknowledge drive sizes beyond 504mb. |
Reset Switch
Switch located on the front of the system chassis. It is activated by a button on the front bezel of the case. When the switch is pressed, it sends a signal to the reset line on the CPU. This causes the system to reboot. |
Reset Switch Connector
A switch located on the front of a computer case that is used to reboot a computer when it locks up. |
Resistor
A small device having electrical resistance that is used in an electric circuit for protection, operation, or current control. |
Resolution
Term used to reference the size of the pixels in a video display. The higher the graphics resolution, the higher the pixel size in general.
A reference to the size of the pixels in a display at a given screen size. The higher the resolution, the smaller the pixels. |
Reverse Address Resolution Protocol (RARP)
The protocol TCP/IP protocol uses to get an IP address when only a domain name address is available. |
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A form of electromagnetic interference that creates noise on an electronic circuit. |
RFI
See |
RG
This term means Radio/Government and defines the rating specifications of the cable based on the cable's type and thickness of its core wire. |
Ring
A LAN topology shaped like a ring whose nodes connect in a closed loop. |
Ripple
Another term for noise. See |
Riser Card
Connected directly to the computer motherboard, this circuit board provides the ability to save space and physically extend a slot in a fully loaded computer for additional capabilities. |
RJ-11
Connector used for telephone and modem connections. |
ROM
Read Only Memory is a type of stored data that never changes, because it is built into a device. It is a non-volatile storage system, because it contains important data that must be saved even when the power is shut off. It is used to hold embedded systems such as the CMOS setup and other boot up data for the computer. |
ROM BIOS Chip
Read-only memory chip. It is programmed with the read-only basic input/output system or BIOS programs that are needed for the system to be able to boot. |
ROM Chip
Read only memory chip. Type of memory chip with its programs permanently burned in. It is used for operations that are only red into memory and are not changeable. |
Root Directory
The base of any file system directory structure. |
Routers
Equipment that transmits information and data, from one local area or wide area network, to another LAN or WAN. |
RPM
Revolutions per minute. The number of times the drive platter spins completely in one minute. |
RS-232
The standard developed for serial interfaces. |
RTC/NVRAM Chip
Another term for the CMOS chip. |
RTS/CTS
Request to Send/Clear to Send. See |
Rubber Dome Switches
This is a variant of the foam buffer design where the spring is eliminated from the plunger and a rubber dome is used in place of the foam and foil laminate pad. The rubber dome sits atop the contacts on the circuit board. |
S
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Wire that connects to a local earth ground and the chassis of an electrical appliance or device via an electrical outlet and plug. The safety ground wire is used to ensure that no voltage potential exists between the chassis of the electrical device and the earth ground. |
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A type of power event. Any decrease that equals 80% below the normal voltage carried by a power line. It is sometimes referred to as a brownout.
See , , , and . |
Sample Rate
In computerized sound, the frequency at which sound samples are taken. The more sound samples taken per time unit, the closer the digitized sound will match the original analog sound. |
Sample Size
The amount of storage designated to a single sound sample when converting analog signals to digital signals. |
Sampling
In computers, the process of changing analog signals to digital format by measuring samples at regular intervals.
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Satellite
An internet connection that is always on, independent of cable or telephone lines for communication, for sending and receiving information via a satellite dish. |
SBIC
SCSI Bus Interface Controller chip. See |
SC Fiber Optic Connector
This connector, sometimes referred to as a square connector, is a latch connector; containing a push-pull mechanism for connection. |
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A unique binary code sent to the motherboard by the on-board keyboard processor based on the key switch position in the key matrix. When the key is pressed, the processor reads the position, and sends the appropriate scan code to the motherboard. |
Scanner
Hardware input device that reads hard copy printed information such as pictures or text and translates them into digital data the computer can understand. |
Scanning
The movement the electron beam makes across the video screen as it writes the image. The scanning movement can be interlaced or noninterlaced. |
Scanning Frequency
Another manufacturer specification listing the horizontal and vertical scan range of a monitor model. I.e., a horizontal scan range of 30 –95 kHz and a vertical scan range of 50 – 150MHz. |
Screen Size
The actual physical size of the monitor screen as measured in inches from one corner diagonally to the other. |
Screen Treatments
A manufacturer specification for the CRT screen detailing the types of screen coating.
Quality monitors generally have tinted screens with anti-static and anti-glare surface treatments. |
SCSI (Small Computer Systems Interface)
SCSI uses a 50-pin connector and allows up to eight devices to be connected in a daisy-chain. The original 1986 SCSI version is sometimes called SCSI-1 to differentiate it from the 1994 SCSI-2 and more recent versions. |
SCSI-1
The first SCSI bus standard. It was ratified in 1986. |
SCSI-2
The second SCSI bus standard. It was ratified in 1994. Enhancements included increased device support and a common set of BIOS commands. SCSI-2 is what most technicians mean today when they refer to SCSI. |
SCSI-2 Fast
A slight variation of the original SCSI-2 standard in which the clock speed was doubled to 10MHz. |
SCSI-3
Standard uses a 16-bit bus, allowing a maximum data transfer speed of 160MB/s. |
SCSI BIOS ROM
SCSI card BIOS that allows a system to boot from a SCSI drive. |
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A logic chip which governs the SCSI controller circuitry on a SCSI drive. |
SCSI bus parity
A parity bit must be sent with each SCSI data transfer to ensure the data's integrity. |
SCSI Card
Type of expansion board that connects to the motherboard. It provides the interface for the SCSI drive to connect to the local bus. |
SCSI Host Adapter
The SCSI host adapter is another SCSI device like any other. Its job is to act as the gateway between the SCSI bus and the host system’s I/O bus. It sends and responds to commands and transfers data to and from devices on the bus and inside the computer itself. |
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Number assigned to devices daisy-chained on a SCSI (Small Computer Systems Interface) drive. |
SDRAM (Synchronous DRAM)
A common type of personal computer memory. SDRAM can run at higher clock speeds than conventional memory. In addition, it synchronizes its clock speed with the CPU. |
Search Engine
A program used to find World Wide Web pages by way of keyword searches. |
Secondary IDE Sector Translation
A method used by the enhanced BIOS of computer systems since the mid-1990s to overcome the drive geometry limitations in the BIOS which limits drive sizes to 504mb. The BIOS takes the logical geometry that the hard disk sends it in response to the Identify Drive command and makes adjustments that will "fit" into the maximums allowed by the BIOS in the 13h standard. This is done by dividing the number of logical cylinders by an integer, and then multiplying the number of logical heads by the same number. The results keep the sectors/track figure within the acceptable limitations of the BIOS. |
Sector
The smallest unit that can be accessed on a disk. Sectors are segments within concentric rings on a floppy or hard disk called tracks. The operating system and disk drive keep tabs on where information is stored on the disk by noting its track and sector number. These normally hold about 512 bytes of data.
The smallest unit of space on the hard disk that any software can access that is 512 bytes in size. |
Sector Translation
A method used by the enhanced BIOS of computer systems since the mid-1990s to overcome the drive geometry limitations in the BIOS which limits drive sizes to 504mb. The BIOS takes the logical geometry that the hard disk sends it in response to the Identify Drive command and makes adjustments that will "fit" into the maximums allowed by the BIOS Int 13h standard. This is done by dividing the number of logical cylinders by an integer, and then multiplying the number of logical heads by the same number. The results keep the sectors/track figure within the acceptable limitations of the BIOS
A method used with SCSI and EIDE disk drives to translate the cylinders, heads and sector specifications of the drive into numbers that can be used by enhanced BIOS. This allows the BIOS to acknowledge drive sizes beyond 504mb. |
Self Monitoring Analysis and Reporting Technology (S.M.A.R.T.)
See |
Semiconductor
A material that allows current to flow under certain circumstances. Usually the material is crystalline. Examples of common crystalline semiconductors are silicon, germanium, gallium arsenide. Semiconductors are used to make diodes, transistors and other basic solid-state electronic components. |
Serial
Transfer of data sequentially, one bit at a time. |
Serial ATA
Serial ATA is a serial link that supports all ATA and ATAPI devices and can only communicate with one device per channel. |
Serial Cable
Type of wiring used to connect devices using serial communication method of data transfer to the motherboard. |
Serial communication
Serial communication occurs when a computer and printer communicate via a serial port, exchanging data over a single cable, a single bit at a time. |
Serial interface
An interface used for the serial transmission of data. In this type of transmission, only one bit is transmitted at a time. |
Serial Port
A port, or interface, that can be used for serial or sequential communication. In this type of communication only 1 bit of data is transmitted at a time. Devices that use serial ports include modems, mice, and printers. |
Server
A server is a computer that runs administrative software that controls workstations on a network. |
Servo Mechanism
The design of the binary notational system called gray code that is burned into the hard drive platters during manufacture. This guides the head actuator mechanism which positions the read/write heads over tracks on the platter. |
Setup Wizard
A Microsoft guide that helps users install and setup a Windows operating system. |
Shadowing
Process of copying BIOS instructions from a slow ROM chip to the higher speed main memory. |
Shadow Mask
A masking design composed of fine metal mesh on the inside of the monitor screen from the top to the bottom. It serves to focus the electron beam on the correct dots much like the aperture grill. The shadow mask is designed to the same shape as the surface of the CRT, and the electron beams shine through the mask. |
Shielded
Shielded twisted pair cable is thin-diameter wire wrapped in a metal or plastic sheath to help eliminate external noise or interference. |
Silicon
Material used as the base for most integrated circuits, especially microchips. |
Sine Wave
A periodic wave generated by an object that vibrates at a single frequency. |
SIMM (Single In-Line Memory Module)
A small circuit-board that holds a group of memory chips. On Macintoshes, SIMMs can hold up to eight chips. On PCs, they can hold up to nine. The ninth chip is used for parity error checking. |
SIMM Slot
The connector used to install SIMM onto the motherboard. A slot on the motherboard that is designed to be used by a SIMM board. |
Signal
Electrical impulse used to transmit data over a physical medium for purposes of communication. |
Signaling Port
Parallel or serial interface of a computer system where data is transferred in or out. Ports are located on the rear of the case. Usually, the signaling ports are made up of 9-pin, 25-pin, SCSI, PS/2, and the keyboard plug. |
Signal-To-Noise Ratio
The ratio of signal clarity to quantization noise which occurs in analog phone communications crossing the PSTN. As analog signal speed increases, so does the noise, until the point where the noise severely grades the signal. This is about 35kbps. |
Simple Mail Transfer Protocol (SMTP)
A standard Internet e-mail protocol that helps to store and forward mail. |
Single Edge Contact (SEC)
Pentium II feature, in which the interface of the CPU contact takes place on one edge only. |
Single-Ended SCSI
The normal SCSI signal standard in which one cable wire is used to carry the signal from end to end. This is opposed to differential SCSI where two wires carry the signal, each the logical inversion of the other. The difference between the two is used by the SCSI controllers to filter out any noise. The effective difference between the two is the greater length of transmission allowed by differential over single-ended SCSI. |
Single In-Line Memory Module (SIMM)
A small circuit-board that holds a group of memory chips. On Macintoshes, SIMMs can hold up to eight chips. On PCs, they can hold up to nine. The ninth chip is used for parity error checking. |
Single In-Line Memory Module
A small circuit board that holds surface-mount memory chips. |
Single-Sided
This term refers to the fact that memory chips are only on one side of the SIMM. |
Single Tasking
The limitation of an operating system to run only one operating task at a time as opposed to concurrent ones. MS-DOS is an example of a single tasking operating system while Windows NT is an example of a multi-tasking operating system.
The ability to execute only one task at the same time. A task is a program or software module. This is opposed to multi-tasking. MS-DOS is a single tasking operating system . Windows 95 is a multi-tasking operating system. |
Singleword
A DMA mode where 16 bits of data may be transferred at a time. |
Sinusoidal
Of, relating to, or shaped like a sine curve or sine wave. |
Slave
Integrated Devices Electronics device in position (s) following the device sequence master. |
Sleep Mode
Sleep mode is state of computer rest or inactivity triggered after a specified amount of time to save power and resources. |
Slimline
A type of form factor in current use. |
Slot 2
On newer Pentium II chipsets, it features a larger contact connector than Slot 1 and allows the CPU to communicate with the L2 cache at full clock speed. |
Small Computer Systems Interface (SCSI)
SCSI uses a 50-pin connector and allows up to eight devices to be connected in a daisy-chain. The original 1986 SCSI version is sometimes called SCSI-1 to differentiate it from the 1994 SCSI-2 and more recent versions. |
Small Drive Connectors
Smaller of the 4 pin power supply connectors. These power supply leads connect to the newer technology 3.5" floppy disk drives and use 5 volt motors to operate. |
Small Outline DIMM (SO-DIMM)
See SoDIMM. |
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A standard method of predicting drive failure by monitoring features susceptible to and conditions indicative of drive failure. |
Socket 3
Motherboard socket where older technology CPUs such as the Intel P24T, P24D, 80486DX4, 80486DX2/DX/SX-SL, and 80486DX2/DX/SX or Cyrix CX486DX2/DX/S and 5X86 or AMD AM486DX4/DX2/DX or UMC U5 connect to the motherboard. |
Socket 7
Motherboard socket where older technology CPUs such as the Intel Pentium P54C and P55C series CPUs or Cyrix 6x86 and Cyrix 6x86L or AMD-K6 series 64-bit processors connect to the motherboard. |
Socket 8
Motherboard socket where the more recent technology Pentium Pro CPUs connect to the motherboard. |
Socket 423
Pentium IV interface with 423 pins |
Socket 478
Pentium IV interface with 478 pins |
Socket 603
Server version of Pentium IV with an interface of 603 pins |
Small Outline DIMM (So-DIMM)
Type of RAM module used in laptop computers, designed to accommodate smaller portable computer interiors. |
Smart multi-station access unit (SMAU)
Centralized connection point in a token ring network. |
Software
Any computer instructions or data that can be stored electronically. It is divided into two categories: systems software and applications software. Systems software includes the operating system and all of the utilities that make it possible for the computer to function. Applications software includes programs that do real work for users. Examples of applications software include Excel and MSWord. |
Solder
To join or bond with a metal alloy. |
Solid Ink Printers
These printers are a color, laser-class printer that first melts the wax based inks into a liquid, squirts or "jets" the liquid onto a drum then applies it to paper. |
Solid state
Electronic part or circuit made of solid materials. A solid state component does not "move," as a mechanical device. Rather, a solid state component operates with electromagnetic action making solid state components faster, and more expensive, than mechanical devices. |
Solvent
Any material which acts to dissolve another. It is the dissolving medium, or liquid portion, of a solution. Water is one of the most frequently used solvents. |
Sound Card
An internal device designed to handle a computer's sound capabilities including input, output, and sound file modification. |
Speaker
A device that enables users to hear sound stored on their computers. |
Speculative Execution
Performs tasks in anticipation of future task loads.
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A type of power event. Any power impulse lasting between .5 and 100 microseconds. Spikes possess an amplitude over 100% of peak power line voltage. See , , and . |
Spindle
The central post or hub on which a disk drive’s platters are mounted. |
Spindle Motor
The small electric motor that spins the disk mounted on the spindle of a floppy drive so that the tracks are under the read/write heads.
The motor in the Head Disk Assembly which powers the spindle to rotate the drive platters.
The motor that spins the hub or spindle on which the CD disk rests. |
Spray Contact Cleaner
A liquid solvent used to clean electronic connections that does not leave a residue. It has a rapid drying time and is inflammable. |
SRAM
Abbreviation for static random access memory. It is a type of memory that is faster and more reliable than RAM. The reason it is called static RAM is because it needs to be refreshed less often than RAM. |
ST Fiber Optic Connector
The ST connector is easy to use; making connections and disconnections fairly easy (only a quarter turn) while using a BNC attachment. |
Standard Parallel Port (SPP)
The original standard in parallel interfaces. SPP originally did not support bi-directional communication. |
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Backup power device that runs off its battery only when regular AC power is interrupted. |
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Type of UPS that is a DC/AC converter operating from battery power. Also called an offline UPS. |
Stand-Offs
Small pieces of hardware that are used to attach the motherboard to the motherboard mounting plate on the chassis. |
Star
A LAN topology in the shape of a star used to connect all nodes to the central computer on the network. |
Start Bit
Begin signal used in the asynchronous transmission of data. It is used for parity-checking.
In a serial communications session, the binary number 0 that precedes every byte to tell the receiving system that the next 8 bits constitute a byte of data. |
Static Electricity
Stationary electricity that results from the buildup of electrons on conductive material. |
Static Mat
Mat made of an anti-static material which provides a grounding source when stood upon while working. The mat absorbs static electricity that could damage electronic components. They are used to help prevent ESD. |
Static RAM
Also known as SRAM. Random access memory that is called static because it will retain a value as long as power is supplied, unlike dynamic random access memory which must be regularly refreshed. It is however, still volatile. SRAM is usually faster than DRAM. |
Stop Bit
End signal used in asynchronous transmission of data. It is used for parity-checking.
In a serial communications session, a data bit that follows the byte (or character) to signal the remote system that it was sent. |
Stopping Point
A part that releases a movement or stops. |
Storage Platter
The fixed media in hard drives that is coated with a magnetically sensitive coating for the reading and writing of data. |
Streaming Video
Technique for transferring video data that allows the viewer to begin seeing the data before all of it is loaded. |
Stylus
A pen-shaped device that allows users the ability to manipulate items and write on a touch-screen display. |
Subnotebook
A smaller-than-notebook portable computer that weighs less than four pounds. Subnotebooks often use an external floppy drive to reduce weight. |
Subwoofer
Speaker designed to exclusively reproduce sounds with lower frequencies and to enhance bass reproduction. Subwoofer speakers are always bundled with a three-to-five piece sound system. |
Super I/O Controller
A chip in the main chip set that manages all of the I/O bus connection points. |
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An extension to the VGA standard, which was introduced by a consortium of companies. Super VGA increased resolution from from VGA's 640x480 to 1024x728. Super VGA was standardized by the Video Electronics Standards Association in 1989. |
Supercomputer
A large very fast mainframe used especially for scientific computations. |
Superscalar Processing
Allows more than one instruction to be enabled by clock cycle. |
Support Resolutions
The range of resolutions supported by the monitor model as specified by the manufacturer. |
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A type of power event. Any voltage increase above 110 % of the normal voltage. See , and . |
Surge Suppressor
A device used to protect equipment from transient power surges that travel from AC power lines and telephone circuits. They are also referred to as surge protectors. |
Switch
Network equipment that is used to allow computers inside of a LAN to communicate with each other. A switch breaks up collision domains and makes forwarding decisions based on computer's MAC addresses. |
SVGA
Super Video Graphics Array. See . |
Symmetric DSL
A digital connection that offers above average data transfer rates like cable, T-1 and T-3 lines. |
Synchronous
A form of data communications in which exchanges of data bits are strictly timed by a clocking signal. |
Synchronous Communication
A form of data communications in which data bit exchange is strictly timed by a clocking signal. |
Synchronous DRAM (SDRAM)
A common type of personal computer memory. SDRAM can run at higher clock speeds than conventional memory. In addition, it synchronizes its clock speed with the CPU. |
Syntax
A connected or orderly system. Harmonious arrangement of parts or elements |
System Board
Another name for the motherboard. |
System File
The System file is the Mac OS operating system's executable portion. System file performs functions such as formatting disks, copying and erasing files, and running application software. |
System Memory
Another term used for RAM. |
System Setup
Term for the system BIOS setup utility used to configure the basic hardware of the computer system. |
System Unit
The computer's case and internal components that allow the computer to process information, store data, and communicate with other parts of the computer. System unit components can include the power supply, motherboard, central processing unit, RAM, ROM, and one or more disk drives. |
T
T-1
A broadband digital communication circuit capable of transmitting 1.55 Mbps. |
T-3
A broadband digital communication circuit capable of transmitting 45 Mbps, the equivalent of thirty T-1 lines. |
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The act of putting data or statistics in table form. |
Tabulator
A device that keeps a record of the number of times something occurs. |
Tactile Feedback Mechanism
A special metal clip and spring arrangement around the plunger of a key switch designed to provide a springy or clicky feel to the user when the key is depressed. |
Tandy
The Tandy Corporation, of Ft. Worth, TX, is the parent company of Radio Shack. The company made the TRS-80 and other early personal computers. |
Tape Drive
A tape drive backup allows data to be safeguarded on removable magnetic media. |
Termination
The sealing of the ends of an electrical bus to maintain the correct impedance for signal propagation and to prevent signal echoes that degrade the quality of data exchange. This is only required today on the SCSI bus, since IDE and floppy drive buses are automatically terminated. This is accomplished via jumpers on the SCSI device called internal termination or with a terminator called external termination. |
Texas Instruments
A large electronics company that has contributed considerably to the computer revolution. Today, it is primarily involved in the production of semiconductors. |
TFT
Thin film resistors are small resistors found in active matrix display screens. |
Thermal Compound
Thermal compound, also known as thermal grease or thermal paste, is a conductive substance used to promote improved heat conductivity between two surfaces, usually between the CPU and heat sink. |
Thermal or Thermal Hot Wax Printers
Thermal or thermal hot wax printer form an image by melting wax that cools and becomes permanent then adheres onto a heat-sensitive paper. |
Thermal or Temperature Sensors
This device provides an easy and accurate way to measure the temperature inside a PC. |
Thin-Film Media
The extremely fine layer of magnetically sensitive cobalt alloy deposited on hard drive platters for data encoding and decoding. |
Throughput
A measure of the data transfer rate through a computer system. |
Token
A data item that travels around a network allowing any connected computer to attach data (to be sent) to it. Without the token, computers on a token passing network cannot send data. |
Token-passing
Local Area Network developed by IBM. Data is passed around the ring in packets (tokens), one token at a time. |
Token Ring
Token Ring is a LAN topography developed by IBM that uses a token ring access method. |
Token Ring Network
A type of local area network design. |
Toner
In laser printers, a very fine powder of plastic particles which are attached to the paper via a charged drum, then fused into the paper by a fuser. |
Toner Hopper
In laser printers, a toner storage bin which sits atop a developer unit and feeds toner to the drum for transference onto the paper. |
Topology
The physical layout of a network. |
Touchpad
A touchpad is a stationary pointing device found on portable computers. A touchpad is a small, flat surface on which you slide your finger to simulate the manipulate the cursor. |
Touch Screen
A hardware input device that allows users to interact with a computer by touching the display screen. Usually touch screens use beams of infrared light that are projected across the screen surface. When the beams are interrupted, an electronic signal is generated which identifies the location on the screen. Software interprets the signal and performs the required operation. One well known use of touch screens is at bank ATMs. |
Tracks
Term for the rings on a floppy or hard disk that contain several sectors. The operating system and disk drive keep tabs on where information is stored on the disk by noting its track and sector number. |
Trackball
Hardware input and pointing device that can perform all of the tasks that a mouse can. Resembling an upside-down mouse, it consists of a ball housed in a socket. It works by using a rotating ball that can be moved with the thumb, fingertips, or palm of the hand. Buttons are used to perform basic clicking actions such as selecting commands from a menu. |
Trackball Mouse
Another type of opti-mechanical mouse for which the design is basically a two-button mouse turned upside down. The roller ball is face-up and is manipulated by a thumb or index finger while the palm rests atop the body. |
Tractor-Feed Device
In dot matrix printers, a paper transport mechanism composed of a pair of sprocket wheels on a rotating bar which fit into the perforated edges of fan-fold paper. This sprocket mechanism either pulls or pushes the paper through the paper path and around the platen for the print head. |
Tractor-Feed Paper
Also called fan-fold paper, tractor-feed paper has perforated edges that can be torn away once the paper has been printed. Tractor-feed paper is used with dot matrix printers. |
Transfer Corona Wire
Positively charged wire designed to pull toner off the drum and place it on the page.
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Transfer Rate
The average speed in kilobytes per second (kbps) at which a drive can read data from a CD and transmit it to a computer in a sustained, sequential manner. |
Transfer Time
The period of time between the instant of initiation of transfer and the instant the load power is transferred from one source to another. |
Transferring
The sixth step in the laser printing process. As paper is fed into a laser printer, the image is transferred to paper. |
Transformer
A device for increasing or decreasing voltage. |
Transient
A momentary variation in power, which ultimately disappears. Surges, spikes, sags, blackouts, noise, etc. are all examples of transients. |
Transistor
A circuit component that typically has three leads, where the voltage or a current controls the flow of another current. |
Transmission Control Protocol/Internet Protocol
TCP checks for errors in Internet access protocols, IP assures proper data routing. |
Trash Bin
The trash bin is a Macintosh desktop icon that acts as a temporary file to hold documents and programs slated to be deleted. |
Tray
The integral loading shelf of a CD-ROM tray-loading mechanism. This shelf usually has an inset in the shape of a CD disk with a hole in the center for the drive spindle to mount the CD and spin. |
Trigonometric Function
A function such as sine, cosine, tangent, cotangent, secant, and cosecant of an arc or angle typically expressed as ratios of pairs of sides of a right triangle. |
Turing Machine
A hypothetical computing machine created in 1936 that was considered a prototype for digital computers. The Turing machine was designed by Alan Turing and used for theory proofs. |
TUV
German-based service organization that rests and certifies product safety to meet standards and specifications of the European Union. |
Twenty-Five (25)-Pin Serial Port
Type of serial port employing twenty-five pins or contacts. |
Twinax or Twinaxial
This cable contains two inner conductors instead of one and is similar to coaxial cable. |
Twisted-pair cable
A thin-diameter wire generally used for telephone and network cabling. |
Two Hundred Eighty-Six (286)-AT
IBM personal computer that followed the IBM PC model. The IBM 286-AT used an Intel 80286 microprocessor. Within 6 years of its introduction, there were approximately 15 million 286-based personal computers installed around the world. |
Type I
PC card 3.3mm thick, generally used for memory |
Type II
PC card 5mm thick, input/output adapter for NICs, SCSI buses and modems. |
Type III
PC card 10.5mm thick, interfaces mass storage devices. |
Tyranny of Numbers
Metaphor used to describe the tremendous difficulties faced by engineers in designing new and improved circuits while still remaining within the limitations of numbers of individual components which could be realistically assembled. |
U
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Universal Asynchronous Receiver/Transmitter. See . |
UDC (Universal Data Connector)
Originally developed by IBM as the IBM Data Connector, is frequently utilized with IBM’s token ring technology and Type 1 or Type 2 STP cabling. |
UDMA
Ultra Direct Memory Access or Ultra DMA. See |
UDMA Mode 2
The highest transfer rate mode supported by the new Ultra DMA protocol through DMA channels on ATA-3 hard drives using bus mastering. |
UL
See Underwriters Laboratories. |
Ultra-2 SCSI
Standard that uses a 40MHz clock and an 8-bit bus, allowing a maximum data transfer speed of 40MB/s.
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Ultra-2 Wide SCSI
Standard that uses a 16-bit bus, allowing 80MB/s. |
Ultra-3 SCSI
Standard that allows 160MB/s, but also includes features that ensure reliable data transfer. |
Ultra 160 SCSI
Standard that uses a validation process during boot-up to ensure that all of the devices on the SCSI chain can be used reliably at maximum speed. |
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A new protocol developed jointly by Intel and Quantum that allows bypassing of the I/O bus bottleneck to take place during peak sequential operations on EIDE hard drives. This new specification basically enables read and write data transfers through DMA channels with and without bus mastering. |
Ultra DMA/66
A bus mastering form of DMA that allows for faster data transfers. UDMA is capable of 33 and 66 MBps data transfers. |
Ultra SCSI
Standard that uses a 20MHz clock and an 8-bit bus allowing a maximum data transfer speed of 20MB/s (also known as Fast-20) |
Ultra-Wide SCSI
Standard that uses a 16-bit bus, allowing 40MB/s. |
Underwriters Laboratories (UL)
An independent non-profit agency within the United States that tests and certifies product safety. |
Underwriters Laboratories of Canada
Canadian division of Underwriters Laboratories. See Underwriters Laboratories. |
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Backup device designed to provide an uninterrupted power source in the event of a power failure. |
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A buffered computer chip which handles asynchronous communications through the computers serial ports. The 16550A is the current generation chip used by most computers. |
Universal Data Connector (UDC)
See UDC. |
Universal Resource Locater URL
An address that defines the best path to a specific Web or Internet file. |
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A new external bus standard. It supports data transfer rates of 12 million bits per second. It is expected to eventually completely replace serial and parallel ports. |
Unix
A powerful multi-tasking operating system capable of running on multiple CPUs at the same time. Developed originally by Bell Labs at AT&T in the 1970’s and still very popular with users requiring powerful systems. Currently is in System V, Release 4. |
Unshielded
Twisted pair cable without inner insulation. Used for telephone and network wiring. |
UPS
See . |
USB
Abbreviation for universal serial bus. See |
USB Connection
Port that uses the new external bus standard that supports data transfer rates of 12 million bits per second. The USB stands for Universal Serial Bus. One USB connection can be used to connect up to 127 peripheral devices, such as mice, modems, and keyboards. This type of port is expected to replace serial and parallel ports. |
USB Speakers
Speakers designed for computers lacking a sound card. |
User Controls
Another manufacturer specification referring to the range of controls available to adjust the operating parameters of the monitor. These typically include power switch, horizontal/vertical size, horizontal/vertical position, pincushion, contrasts, and brightness controls. |
User-Friendly
Describes a system that is easy to learn and use. |
User Interface
The command line or graphical shell through which the user enters the operating system commands. |
User’s Manual
The booklet that accompanies your new computer. A good Users Manual should explain setup, installation and, and use of your computer and its main features. |
User Friendly
A system that is easy to learn and easy to use. |
V
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The ITU data compression standard supported in all modern modems. |
Vacuum Tube
An electronic component consisting of a space exhausted of gas to such an extent that electrons may move about freely, and two or more electrodes with external connections. |
Variable Frequency Synthesizer Circuit
Motherboard circuit that multiplies the clock signal so that the motherboard can support several speeds of CPUs. |
Variable Frequency Synthesizer Circuit
Motherboard circuit that multiplies the clock signal so that the motherboard can support several speeds of CPUs. |
Vertical Scan Rate
Also called the vertical scan frequency, expressed in Hertz (Hz). This governs the refresh rate of the screen display. A vertical scan rate of 70Hz or higher is considered ideal. |
VESA BIOS Extension
A BIOS extension to the VGA standard introduced by member companies of the Video Electronics Standards Association in 1989 to resolve incompatibilities in their implementations of the SVGA display technology. This provided a standard interface for programmer to write the drivers for their SVGA video adapters. |
VESA DPMS
A power management signaling specification developed for monitors by the Video Electronics Standards Association. See Display Power Management System. |
VGA
See . |
Video Adapter
An expansion board that plugs into a computer system to give it display capabilities. The video adapter, in conjunction with the display monitor, forms the video system for the computer. |
Video Bandwidth
The total amount of memory that can be read at one time. This performance factor is related to the frame buffer size and speed of the video memory. The faster the video memory, the more bits can be moved from the frame buffer at once to the screen. This speed is usually measured in megahertz (MHz). It is a factor in overall video performance, in large part determining the ability of the card to support higher resolutions and color depths, at reasonable refresh rates. |
Video BIOS
BIOS on the video card which provides a set of video-related functions that are used by programs to access the video hardware. This is much the same way the system BIOS provides the functions that software programs use to access the system hardware. |
Video Display Monitor
Another term for monitor, display monitor, or video monitor. |
Video Chip Set
This is the logic circuit that controls the video card. It almost always includes an internal processor that performs various video calculation functions before the RAMDAC chip outputs to the monitor. |
Video Electronics Standards Association
An organization founded in 1989 by the nine leading video board manufacturers to standardize the technical issues surrounding the Super VGA video display. This organization has also been involved in other issues since then. |
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The first analog video graphics standard introduced by IBM Corporation in 1987. |
Video Memory
The amount of RAM on the video card used by the video chipset to draw the requested screen display. |
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A type of specialized DRAM memory chip on video boards designed for dual port access. This means that it has two access paths, and can be written to and read from simultaneously. |
Viewable Area
One of the primary manufacturer specifications for the screen display. The actual area usable to a screen image as opposed to the screen size, because there is always a non-usable black border around it. |
Virus Scanning and Repair Disk
Disk used to start a virus detection program. It is usually bootable. It may also have a "fdisk" utility to run tests and repair the hard disks. |
VL-Bus
A 32-bit bus that runs up to 40MHz. Featured on 486 motherboards, VL-buses offered up to three slots and peripheral data transfer bandwidth greater than ISA bandwidth. |
Voice Coil Actuator
The device that moves the head actuator assembly with read/write heads across the hard disk platters by electromagnetic attraction or repulsion of its wire coils again a magnet. This positions it precisely over the required track. |
Volatile
Memory that loses its contents when the power is turned off. Random Access Memory (RAM) for example, is volatile. |
Volatile Memory
Term used to describe RAM because its memory is temporary. When power to the computer system is turned off, data that is stored in RAM will be lost unless it has been saved to hard disk. |
Volatile Storage
Term used to describe RAM because its memory is temporary. When power to the computer system is turned off, data that is stored in RAM will be lost unless it has been saved to hard disk. |
Voltage Inverter
Device in the online UPS. It converts DC current from the battery to AC current that can be used by the power supply. |
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A module which is designed to provide the correct voltage to the CPU. |
Voltage Switch
Lever located on the back of the power supply that allows the user to switch between the 115 volt current used in the United States and the 230 volt current used in most other countries. |
Volume
A fixed amount of storage on a disk created by formatting a partition. The volumes contain the actual file management system utilized by an operating system. |
Volume Boot Code
Another term for the bootstrap loader which launches the operating system. |
VRAM
See |
VRM
See . |
W
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A delay of one or more clock cycles added to a processor's instruction execution time to allow it to communicate with slow external devices. The number and duration of wait states may be pre-configured, or they may be controlled dynamically via certain control lines. |
Wait States
A clock tick during which nothing happens. They occur between cycles and are used to ensure that the processor does not get ahead of the rest of the computer. |
WAN
Acronym for . |
WAV
Sound files stored as waveforms, characterized by the. wav file extension. |
Wavetable Synthesis
State-of-the-art sound synthesis using actual instrument sound rather than recorded instrument sound. |
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A network that connects clients over large geographical areas (e.g., countrywide or worldwide). |
Waveform
Representation, usually graphic, of the shape of a wave. The representation indicates the wave’s characteristics. These are frequency and amplitude. Also called a waveshape. |
Web Page
A collection of text, pictures, graphics, animations, video, sounds or hypertext links with a specific URL, located on a Web server. |
Web site
A server that contains Web pages, and continuously makes a page available on the Internet. |
Wide SCSI-2
A variant of SCSI-2 which utilizes the 16-bit bus standard over a 68-pin connector. |
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A modification of VRAM that both improves performance and reduces cost. Designed specifically for use in graphics cards, WRAM is also dual-ported but has about 25% more bandwidth than VRAM. It also incorporates additional features to allow for higher performance memory transfers. |
Windows 95
Microsoft's successor to the Windows 3.11 operating system for PCs. Released in 1995, Windows 95 is a complete operating system rather than a graphical user interface running off of MS-DOS. |
Windows 98
The next generation of Windows 95. It was originally called Memphis and then Windows 97. Its most visible feature is the Active Desktop that integrates Internet Explorer with the operating system. |
Windows 2000
Windows 2000 is the latest Microsoft operating system launched in February 2000. |
Windows 2000 Server Family
Windows 2000 Server Family is the server version of Microsoft's Windows 2000 operating system. |
Windows 2000 Professional
Windows 2000 Professional is the desktop and notebook version of Microsoft's Windows 2000 operating system. |
Windows NT (Windows New Technology)
Windows NT is a 32-bit operating system released by Microsoft to be used by servers, high-end workstations, and corporate networks. |
Windows NT 4.0
A robust, multi-tasking graphical interface operating system developed by the Microsoft Corporation. This OS is modular in that the kernel can support applications developed for other operating system environments such as MS-DOS, Windows 3.1, Windows 95, and OS/2. Although not as stable or mature as the Unix operating system currently, this OS is undergoing rapid development and is becoming increasingly popular. |
Windows NT v5.0
The next generation of Windows NT currently in development by the Microsoft Corporation. |
Wireless
Nicknamed the ‘golden child of telecommunications’, this communication technique is a radio transmitted connection between sender and receiver that take place via airwaves. |
Wireless AP (Access Points)
See . |
Word
Computer’s natural storage unit, typically consisting of 8 bits, 16 bits, 32 bits, or 64 bits. |
World Wide Web
The World Wide Web, abbreviated WWW, consists of all the documents on the Internet. Written in Hypertext Markup Language or HTML, the WWW locates documents by their Uniform Resource Locators or URL addresses. Routers are able to "decide" on data's best pathway across networks. |
WRAM
See . |
Wrap Plug
See |
Write Multiple
An ATA-2 enhanced BIOS drive command that enables the controller and drive circuitry to support multiple sector disk reads concurrently. |
Writing
The fourth step in the laser printing process. A small negative charge is applied to the drum, over the charge applied during conditioning. The small negative charge leaves marks on the drum.
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X
X Window System
X Windows System is a windowing system designed to run beneath UNIX and other major operating systems. X Windows allows users to run applications on remote computers on the network, while viewing output on their own screen. |
Xerox
XEROX is a leading manufacturer of analog and digital copy machines, computer printers, and document management systems, headquartered in Stamford, CT. |
Y
Z
A type of socket for integrated circuits that can be opened and closed by means of a lever or screw. When open, the chip may be placed in the socket without any pressure at all. Then, the socket is closed, causing its contacts to grip the pins of the chip. |
