Computer Glossary

Many terms are "dated" at this time but are included for backward compatibility.

16550 UART
A high speed chip for controlling serial ports. Although unnecessary for a mouse, it is required for modems that are 14,400 baud or faster.

6x86
Designation given to the Cyrix Pentium-compatible processors. They range in speeds from 120 - 200. The "L" class of the processors (6x86L) are designed as low power processors, similar to the MMX processors, and run using a split rail voltage. In order to run a Cyrix 6x86L processor, your motherboard must have support for split-rail or dual core voltage processors. For more information, visit the Cyrix Web Site.

AGP
An acronym for Advanced Graphics Port. A new bus port (an enhancement to the PCI bus) that accelerates graphics data throughput.

APM
An acronym for Advanced Power Management. The APM specification defines a layer of software that supports power management in computers with power manageable hardware.

Asynchronous
Operations that do not require the clocks of communicating devices to be coordinated. See Synchronous.

ATX
A system board size measuring approximately 12" x 9.6".

Bidirectional Parallel Port
A type of parallel port that can send and receive information.

BIOS
An Acronym for Basic Input/Output System. Configures the system board and provides hardware information to the operating system.

Bit
A contraction of Binary digit. The smallest unit of information in a binary number system. A bit represents a choice between either zero or one.

Boot
To start up the computer and load the operating system software. See cold boot and warm boot.

Buffered DIMMs
The 168-pin buffered DIMM modules use buffer logic chips on their control lines to reduce loading on the system board. This buffering action increases the maximum number of modules on the same system board. The buffered DIMMs come with standard DRAM chips for 3.3V operation.

Bus
A group of electronic paths used to send data between parts of the system. On a system board, the bus connects the peripheral cards
with the microprocessor via the expansion slots.

Bus Mastering
The ability of a peripheral card to control the bus without requiring intervention of the CPU.

Byte
A group of adjacent bits treated as a unit. Eight bits are typically considered one byte. Also called a character.

Cache
A process where information is copied from the slower memory (DRAM) to the faster memory (SRAM). Information that is likely to be read or edited is stored in the cache providing significant performance increases.

Cold Boot
Starting the computer by turning on the power or pressing the RESET button. A cold boot makes the processor execute all of the diagnostics. See boot and warm boot.

CPU
An acronym for Central Processing Unit. A CPU performs arithmetic calculations, makes logical decisions, and directs the operation of the computer in conjunction with the operating system.

DIMM
An acronym for Dual Inline Memory Module. A small printed circuit board containing memory chips.

Disk Drive
A hardware device which provides for the storage of data on diskettes or hard metal disks that have a magnetic coating. A disk drive functions by spinning at high speed while moving a device called the read/write head across the disk's surface in order to read or write data in magnetic code.

DMI
An acronym for Desktop Management Interface.

DRAM
An acronym for Dynamic Random Access Memory. A type of memory chip that only keeps its memory if supplied with regular clock pulses and a chance to regularly refresh its data. It is slower and more cost effective than SRAM. See SRAM.

ECC
An acronym for Error Checking and Correction. ECC enables parity checking and can detect and correct memory errors on the system board.

ECP
An acronym for Expanded Capabilities Port. A standard set by Hewlett Packard and Microsoft Corporation to expand the capabilities of the parallel port.

EDO Memory
An acronym for Extended Data Out. A DRAM performance feature that permits multiple bit of data in a single row to be accessed quickly.

EISA
An acronym for Extended Industry Standard Architecture. EISA is a bus design standard which is fully backward compatible with the ISA bus. Although it is a 32 bit bus, it only runs at 8mHz.

EPP
An acronym for Enhanced Parallel Port. A standard which increases the capabilities of the parallel port.

EPROM
Acronym for Erasable Programmable Read Only Memory. A type of ROM chip that can be programmed with relatively simple tools that will retain its data until erased. It can only be erased by exposing the circuitry in the chip to ultraviolet light. See also Flash ROM.

Fast SCSI
A SCSI data transfer rate standard that allows a rate of up to 10 MBytes/sec on an 8 bit SCSI bus and up to 20 MBytes/sec on a 16 bit (Wide) SCSI bus.

Flash ROM
A type of ROM chip that will retain its data until erased. It can be erased or reprogrammed by supplying it with +12V of voltage. See ROM and EPROM.

FPM
An acronym for Fast Page Mode. A timing option that permits several bits of data in a single row on a DRAM to accessed at an accelerated rate.

Gigabyte
A disk storage capacity measurement. Approximately one thousand megabytes or 1,073,741,824 bytes.

IDE
An acronym for Integrated Device Electronics. A standard for communicating between a hard drive and a computer.

Internal Cache
Cache which is built into the CPU. See Cache.

ISA
An acronym for Industry Standard Architecture. A well-established bus standard that originated with the IBM AT. See PCI and VESA Local Bus.

LM78 Hardware Monitoring Device
LM78, by National Semiconductor, is a data acquisition chip used to monitor cooling fan speeds, CPU temperatures and power supply voltage levels. It provides the hardware support for remote management software, (e.g. Intel's LanDeskTM) to keep maintenance costs to a minimum while providing real time remote management. Micronics products such as the M6DPi, Dual Fortress, Thunderbolt, Invader ATX, Tigercat and Spitfire EX all have the LM78 hardware monitoring capabilities.

MMX
A set of instructions incorporated into new Intel and AMD processors. This new code accelerates multimedia, graphics, audio, and disk access. Some newer applications like Adobe Photoshop 4.0 and Epic MegaGames Unreal are written to take advantage of this code to accelerate the processing speed and provide increased multimedia performance. For more information, please visit the Intel MMX Web Site.

NS
An acronym for Nanosecond. One billionth of a second. Measure of the access time of RAM.

Parallel
A form of data transmission in which the data is sent one byte at a time over several wires that each carry one byte. In parallel transmission, all the bytes arrive simultaneously, as opposed to serial transmission in which bits arrive one by one.

Parallel Port
A connection for a printer or similar peripheral. Generally, parallel ports are output only. See Bidirectional Parallel Port and ECP.

Parity
Logic that detects the presence of an error in memory. Generally, a single parity bit is used for each byte (8 bits) of data. The most commonly used forms of parity are even parity, odd parity and checksums.

PCI
An acronym for Peripheral Component Interconnect. A high performance 32-bit or 64-bit bus developed by Intel Corporation. PCI is designed to be independent of the hardware architecture to ensure compatibility with future computer systems. See VESA Local Bus and ISA.

Pentium
A high performance 64-bit CISC processor designed and manufactured by Intel Corporation. For more information, please visit the Intel Web Site.

Pipeline
In DRAMs and SRAMs, a method for increasing the performance using multistage circuitry to stack or save data while new data is being accessed.

Plug and Play
A standard developed to ensure easy installation of peripherals. Theoretically, a newly installed card will automatically configure itself and work properly without requiring jumper configuration or device drivers.

POST
An acronym for Power On Self Test. A diagnostic program that is run whenever the system is cold booted.

RAM
An acronym for Random Access Memory. A type of memory that is used as the "working memory" of a computer system. See DRAM and SRAM.

ROM
An acronym for Read Only Memory. A type of memory that retains its data without requiring power. Once written, it cannot be modified. See EPROM and Flash ROM.

S-Spec
This is a 5 digit code, beginning with the letter 'Q' or 'S'. This identifies the Stepping of the processor. See Stepping below.

Serial Port
A communications port used to connect peripherals such as modems and mice.

Setup
A program that allows you to make changes to the system configuration.

Shadow RAM
A technique used to load a duplicate copy of BIOS from slower ROM into faster RAM. This enhances system performance because it provides higher access speed to the BIOS.

SIMM
An acronym for Standard Inline Memory Module. A small printed circuit board containing memory chips.

SDRAM
Synchronous Dynamic Random Access Memory or Synchronous DRAM. A DRAM designed to deliver bursts of data at very high speed using automatic addressing, multiple page interleaving and a synchronous (or clocked) interface.

SRAM
An acronym for Static Random Access Memory. A type of memory that can retain data without requiring a regular clock signal. Although they are faster than DRAM, they hold less data and are more expensive.

Stepping
Each time Intel or Cyrix releases a new revision of processor, they give it a separate stepping number. Steppings are usually issued to correct errata (aka 'bugs') that have been discovered in processors, or that signify a voltage change. For more information on differences between steppings on Intel Pentium processors, visit Intel's Pentium Design Center or for the Pentium Pro numbers, check out Intel's Pentium Pro Design Center.

Synchronous
Protocols that require the clocks of communicating machines or devices to be coordinated.

Synchronous Cache
A type of cache that uses a clock signal to latch the inputs and the data output. This structure spreads the cache access across two or three cycles while maintaining a bandwidth of one access per cycle. Improves performance by 5-10%.

Terabyte
A measurement for very large storage capacity. One Terabyte is equivalent one-thousand gigabytes, one-million megabytes, or 1,099,511,627,766 bytes.

Ultra DMA/33 IDE
A hard drive interface protocol that increases the burst data transfer rate to 33MBytes per second.

Unbuffered DIMMs
The unbuffered DIMM modules do not use any buffer logic chips, thus achieving faster operation due to the elimination of the propagation delay of the logic buffer. This increase in speed comes at the cost of reducing the maximum number of modules on the same system board.

USB
An acronym for Universal Serial Bus. The simple and flexible way to connect devices to your desktop or notebook PC. USB allows virtually unlimited PC expansion with no more hassles over add-in cards, dip switches, jumper cables, software drivers, IRQ settings, DMA channels and I/O addresses. With USB, you can attach and detach peripherals without opening the computer or even shutting it down.

VESA
An acronym for Video Electronics and Standards Association.

VESA Local Bus (VL-Bus)
A high performance bus designed by VESA. A 32-bit version of the ISA bus which operates at the speed of the computer's CPU. See PCI and ISA.

VGA
An acronym for Video Graphics Array. A standard for monitor displays.

VR
Pentium CPU voltage ranging from 3.300 - 3.465 Volts.

VRE
Pentium CPU voltage ranging from 3.400 - 3.600 Volts.

VRM
Voltage Regulator Module. Supplies CPU specific voltages for the CPU.

Warm Boot
Restarting the system by simultaneously pressing the (Cntrl), (Alt) and (Delete) keys.

Wide SCSI
A SCSI-2 enhancement that allows data to be transferred 16 or 32 bits at a time on the SCSI bus instead of 8 bits at a time.

Write-Back Cache
Upon a cache hit, the cache is updated and the main memory is not affected. Upon a cache miss, only the main memory is updated.

Write-Through Cache
Upon a cache hit, the cache and the main memory are updated. Upon a cache miss, only the main memory is updated.