PC Hardware Glossary

A simple guide to PC hardware terminology.

3-D RAM

Video RAM designed to improve 3-D graphics.

80 pin IDE cable

IDE cable with 80 pins. Forty of these pins are ground wires used to reduce crosstalk.

AGP Slot

Slot on the motherboard designed for a video card.

Active matrix

Type of display which amplifies the video signal at every intersection in the grid of electrodes to improve quality.

Active terminator

Terminator used on single ended SCSI cables which includes voltage regulators.

Adapter card

Circuit board used in expansion slots. Also known as expansion cards.

Address bus

Used by CPU to communicate memory and I/O address to memory controller and I/O devices.

ATC

Type of L2 cache in Pentium processors that is embedded on the same core processor die as CPU.

Ammeter

Meter that measures electrical amperage of electrical current.

Amplifier repeater

Repeater that does not distinguish between noise and signal and amplifies both.

Asynchronous SRAM

Static RAM that doesn't work in step with CPU clock rate.

AT

Type of PC form factor. Also called Full AT.

ATX

Most widely used form factor for PCs.

Autorange meter

Multimeter that senses the quantity of input and sets range automatically.

Baby AT

Smaller version of AT form factor.

Back side bus

Bust between the CPU and L2 cache.

Backplane system

Form factor which has no true motherboard.

Bank

Location on motherboard that contains slots for modules of memory.

Beam detect mirror

Detects presence of laser printer's laser beam.

BNC connector

Used with thin coaxial cable.

Brouter

Functions as both a bridge and a router.

BEDO

Version of EDO with improved access time.

Bus

Paths or lines on a motherboard that carries data, instructions and electrical power.

C-RIMM

Placeholder for a RIMM module that provides continuity.

Cable modem

Used with cable internet service. The cable modem connects to the NIC in a PC.

Capacitor

Stores and electrical charge. Used to smooth of the flow of electrical current.

CD-R

Drive that can write data to a CD.

CD-RW

Drive that can write data to a CD. The data can then be erased and rewritten.

CPU (Central Processing Unit)

The CPU receives data input by the user, processes information and executes commands. In a PC, the CPU is housed in a single chip called a microprocessor.

Chip creep

Process in which chips loosen due to changes in temperature.

Chip set

Group of chips on the motherboard that controls the timing and flow of data and instructions to and from the CPU.

Circuit board

Device that contains electrical circuits and chips.

Clock speed

Speed or frequency of a processor.

CMOS configuration chip

Chip on the motherboard that contains setup information about a PC.

Coaxial cable

Networking cable used with ThinNet or ThickNet.

Compact case

Low-profile case used for low-end desktop PCs.

Crossover Cable

A cable used to connect two PCs into a very simple network or connect two hubs.

Data bus

Lines or paths on the system bus that the CPU uses to send and receive data.

Data cartridge

Tape medium used for backups.

Device driver

Program that tells the PC how to communicate with and I/O device.

DIMM

Circuit board used to hold memory.

Diode

Electronic device that allows electricity to flow in one direction.

DIP switch

Switch that can be set on or off. Holds configuration data.

Direct rambus DRAM

Memory technology that uses a narrow and fast system bus. Stored on a RIMM module

DMA channel

Channel in which a device can pass data to memory without involving the CPU.

DMA transfer mode

Used by devices, such as hard drives, to transfer data to memory without involving CPU.

DDR SDRAM

Memory technology used on DIMMs that runs at twice the speed of the system clock.

Dual-voltage CPU

CPU that requires two different voltages.

DRAM

Memory that requires refreshing every few milliseconds.

ECC

Checks integtrity of data stored on DIMMs and RIMMs and corrects single-bit errors in a byte.

ECP

Parallel port mode that uses a DMA channel for increased performance.

EEPROM

Chip in which a high voltage can be applied to one of the pins to erase data before new data is written.

EISA bus

A 32-bit bus that can transfer 4 byts at a time at a speed of about 20 MHz.

EIDE

Interface for secondary storage devices (hard drives) in a PC.

EPP

Parallel port that allows data to flow in both directions for improved performance.

EPROM

Chip that allows data to be erased with a special ultraviolet light so the chip can be reprogrammed.

Expansion bus

Bus that does not run in sync with the system clock.

Expansion card

Circuit board that is added to the motherboard to increase capabilities.

Expansion slot

Slot on the motherboard where an expansion card can be added.

FireWire (IEEE 1394)

Expansion bus that can work as a local bus.

Flash memory

RAM that can hold data when powered off.

Flash ROM

ROM that can be reprogrammed or changed without replacing chips.

Flat panel monitor

Monitor that uses and LCD panel.

FlexATX

Version of ATX that allows for maximum flexibility.

Form factor

Set of standards on the size, shape abd configuration on devices such as power supplies, cases and motherboards.

Gigahertz (GHz)

One billion cycles/second.

Graphics Processor Unit (GPU)

Specialised microprocessor used for video cards.

Graphics accelerator

Video card with a dedicated processor to improve video quality and increase speed.

Half-life

Amount of time for a storage device to weaken to half its strength.

Hard boot (Cold boot)

Turning of and restarting or pressing PC reset button.

Hard copy

Output from printer to printed page.

Hard drive

Main secondary storage device of a PC.

Hardware interrupt

Caused by device signaling that it requires service.

HD-DVD

DVD standard that supports high def video encoding.

Head

Top or bottom surface of a platter in a hard drive.

Heat sink

Piece of metal that can be mounted to chips to dissipate heat.

Hertz (Hz)

Unit of measurement for frequency.

Hot swappable

Component that can be plugged into a PC while it is running. The PC registers the device and configures it without rebooting.

Hub

Network component that provides a central location to connect cables.

Hyper-threading

Technology trademarked by Intel that enables a processor to appear as two logical processor. Each logical processor can execute a thread of a multi-threaded program which can improve performance in certain conditions.

IDE

Hard drive with disk controller integrated ibto the drive.

Intelligent UPS (Smart UPS)

UPS that can be managed with software.

Interlaced

Display in which the monitor only draws every other line.

Internal bus

Bus located in CPU used for communication between CPU and components.

Internal cache

Memory cache contained inside the CPU. Faster than external cache.

ISA

Older interface which can only support an 8 or 16-bit data path.

Jumper

Two wired located on the motherboard that hold configuration data.

Keyboard

Input device through which data can be input the PC.

LAN (Local area network)

Network that covers a small area.

LCD (Liquid crystal display)

Flat panel display used in PC monitors and various other electronic devices.

Line conditioner

Device that regulates electrical power.

Line-interactive UPS

UPS with shorter swiching time. AC to DC converter is constantly running.

Local bus

Bus that works ata s speed synched with the CPU frequency.

Local I/O bus

Bus that provides I/O devices with access to the CPU.

Logical drive (Volume)

Section of the hard drive the OS sees as a physical drive.

Low-level format

Creates the tracks and sectors on a hard drive.

LPX

Form factor that uses riser cards plugged into the motherboard to install expansion cards.

MAC address

Hexadecimal address unique to each NIC.

Master boot record

First sector on hard drive. Contains program for booting and the partition table.

MDRAM

Type of RAM used on video cards.

MHz (Megahertz)

One million cycles per second.

Memory

Microchips that can hold data and programs.

Mini ATX

Smaller ATX board. Can be used with ATX cases and PSUs.

Mini-LPX

Smaller version of LPX.

Modem

Modulates digital data to an analog format that can be trnsported over telephone lines and demodulated back to digital. MOdulate and DEModulate.

Monitor

Used to display text and graphics output from PC.

Motherboard

The main board of a PC. Also called system board.

Mouse

Input device that allows a user to move a cursor on screen and select items.

MP3

Compression method used on audio files.

Multimeter

Device used to measure and test components in an electrical system.

Multiplier

The bus speed multiplied by the multiplier gives the CPU clock speed.

NIC (Network interface card)

Expansion card used to give a PC networking capabilities.

NLX

Form factor similar to LPX but with more support for current processor technology.

Non-volatile

Type of RAM that can hold data as long as it is powered.

North Bridge

Connects I/O buses to the system bus.

Null modem cable

Cable that allows two devices to communicate. Transmit and receive wires are cross-connected and no modem is required.

Overclocking

Increasing the clock rate or frequency at which a device runs. The CPU and video card can are two devices that can be overclocked, among others.

P1 connector

Power connector used by ATX motherboards.

P8 connector

One of two power connectors used by AT motherboards.

P9 connector

One of two power connectors used by AT motherboards.

Parallel ATA

IDE cabling method in which a 40 or 80-pin cable is used with a 40-pin IDE connector.

Parallel port

25-pin port on a PC.

Patch cable

Network cable used to connect a PC to a hub.

PC Card

Adapter card for notebooks used for connecting modems, networks, and CD-ROM drives.

PCI bus

Bus that runs at speed up to 33 MHz or 66 MHz with a 32 or 64-bit data path.

PCI Express

Implementation of the PCI bus based on a much faster serial physical-layer communications protocol.

PDA (Personal digital assistant)

Handhel PC with its own OS and applications.

Peripheral

A peripheral is a device that communicates with the CPU that is not located on the motherboard.

PAC (Pin array cartridge)

Houses the Intel Itanium CPU.

Pinout

How each pin on a bus, connector or socket is configured.

Pits

Areas on the surface of DVDs or CDs used to represent data.

Pixel

Small dot on a scan line. Images on the monitor are made up of pixels.

PnP (Plug and Play)

Automatically configures devices during installation.

Polling

When the CPU checks a device to determine if they are ready to send and receive data.

Port

Physical connector, 2. Another name for an I/O address.

Power Conditioner

Regulates power and provides continuous voltage.

Power Supply (PSU)

Supplies power to all devices in a PC.

Printer

Produces printed output to paper.

Protocol

Set of rules and standards.

PS/2 mouse

Mouse that plugs into the PS/2 port on the motherboard.

RAID (Redundant array of independent disks)

Method used to configure multiple hard drives for better performance and fault tolerance.

RAMDAC

Short for Random Access Memory Digital-to-Analog Converter. The RAMDAC is a single chip located on a video card. The RAMDAC's role is to convert digitally encoded images into analog signals that can be displayed by a monitor.

RAM drive

Memory that works as a hard drive. Much faster than a standard platter hard drive.

RAM (Random Access Memory)

Memory modules installed in the motherboard used for temporary data storage.

Read/write head

Device that reads or writes data to a disk.

Rectifier

Converts AC current to DC current.

Refresh rate

Number of times in a second an electronic beam can fill a monitor screen from top to bottom.

Repeater

Device that amplifies a signal so it may be sent for longer distances.

Resistor

Device that opposes the flow of electrical power.

RIMM

Memory module developed by Rambus.

RJ-11

Phone line connection found on devices such as modems.

RJ-45

Connection type used with a twisted pair cable on a network.

ROM (Read-only memory)

Chip that contains a program that can not be deleted.

Router

Device used to connect networks.

SCSI (Small Computer System Interface)

Interface between a host adapter and the CPU that can contain as many as 15 devices on a single bus.

SCSI ID

Number assigned to a SCSI device.

Secondary storage

Device that permanently holds data such as hard drives.

Sector

A segment of a track on a hard drive disk that has a capacity of 512 bytes.

SATA (Serial ATA)

Cabling method that uses a smaller cable than a 80-pin PATA cable. Is more reliable and faster than PATA.

Serial port

Used for transfering data one bit at a time.

Shielded twisted-pair cable

Cable that has one or more twisted pairs of wires surrounded by a metal casing.

Signal-regenerating repeater

Repeater that can detect the difference between noise and a clear signal and filters out the noise.

Single-voltage CPU

Requires one voltage for all operations.

Slack

Wasted space on a hard drive.

SLI (Scalable Link Interface)

Technology developed by Nvidia that allows two PCI Express video cards in the same PC to be linked so they can share the processing load.

SO-DIMM

Type of DIMM module used in notebook computers.

SO-RIMM

Type of RIMM module used in notebook computers.

South bridge

Part of the chip set that connects slower I/O buses to the system bus.

SPGA (Staggered Pin Grid Array)

Method used on CPU socket to allow for more pins in a smaller space.

SSD (Solid State Drive)

Storage device that holds data like a standard hard drive, but functions with no moving parts and achieves much faster transfer rates, uses considerably less power and has lower latency.

Static RAM

RAM module that holds data with the need for refreshing as long as the PC is powered up.

Surge protector

Device used to protect electrical components from power spikes and surges.

Switch

A network hardware device used to segment a network.

Synchrnous DRAM (SDRAM)

Type of RAM that runs in sync with the system clock.

Synchrnous SRAM

Type of SRAM. Is faster than asynchrnous SRAM.

System Bus

Bus between the memory and CPU. Also known as the memory bus, external bus, host bus or front side bus.

System Clock

Provides a continuous pulse that PC devices used to time themselves.

Terminating Resistor

Resistor used to dampen the voltage near the end of a SCSI chain.

Thermal Printer

A line printer that uses a wax based ink.

Trace

Wire on a printed circuit board that provides a connection.

Tracks

Circles on a medium used to divide a disk.

Transceiver

Located on a NIC. Responsible for signal conversion.

Transformer

Used to change the ratio of current to voltage.

Transistor

Device used to control the flow of electricity.

UART Chip

Chip that controls serial ports.

UDF

File system used for optical mediums.

UPS (Uninterruptible Power Supply)

Provides a backup power source during power failures.

Video Card

Expansion card installed in a PC to provide video capabilities.

Volt

Measure of potential difference in an electrical circuit.

Voltage

Electrical difference that causes current to flow.

Voltmeter

Used for measuring AD or DC voltage.

Watt

Unit used to measure power.

Wattage

Electrical power. Measured in watts.

ZIF (Zero Insertion Force) Socket

Smaller lever used to secure the processor into the socket.