ACCESS TIME Time the processor takes to read data, instructions, and information from memory
ADAPTER CARD Circuit board that provides connections to peripherals
ARITHMETIC LOGIC UNIT Performs arithmetic, comparison, and logical operations
BAY Opening in the system unit in which you can install additional equipment
BIT Smallest unit of data a computer can process
BLUETOOTH Uses radio waves to transmit data between two devices
BUS Allows the devices inside and attached to the system unit to communicate
BYTE 8 bits grouped together
CHIP Small piece of semiconducting material on which integrated circuits are etched
CLOCK SPEED The pace of the system clock
CMOS Uses battery power to retain information when the computer is turned off
CONNECTOR Joins a cable to a port
CONTROL UNIT Processor component that directs most of the operations in the computer
DOCKING STATION External device that provides power connections
DRIVE BAY Rectangular openings that typically hold disk drives
EXPANSION BUS Allows the processor to communicate with peripherals
EXPANSION SLOT Socket on the motherboard that can hold an adapter card
FIRMWARE ROM chips that contain permanently written data
GIGABYTE One billion bytes
GIGAHERTZ One billion ticks of the system clock per second
IRDA PORT Enables devices to transmit data via infrared light rays
KILOBYTE 1,024 bytes
MACHINE CYCLE Fetch, decode, execute, store
MEGABYTE One million bytes

MEMORY MODULE Small circuit board on which RAM chips reside
MIDIPORT Connects the system unit to a musical instrument
NONVOLATILE MEMORY Memory that does not lose its contents when the computer's power is turned off
PC CARD Device that adds memory, storage, and other capabilities to mobile computers
PORT Point at which a peripheral attaches to a system unit
RANDOM ACCESS MEMORY Main memory
SCSI PORT Allows you to attach peripherals such as disk drives and printers
SOUND CARD Enhances the sound-generating capabilities of a personal computer
SYSTEM BUS Connects the processor to main memory
SYSTEM UNIT Case containing the electronic components of the computer
TERABYTE One trillion bytes
USB FLASH DRIVE A flash memory storage device that plugs into a USB port
USB HUB Device that contains multiple USB ports
USB PORT Can connect up to 127 different peripherals together with a single connector type