CIS 105 -- Survey of Computer Information Systems

Essential Concepts and Terminology -- Study Unit Two.

The smallest unit of information handled by a computer. A bit can hold one of two values, either a 0 or a 1.
An eight-bit unit of information, often representing a single character.
Data Transfer Rate.
The speed (measured in kilobits per second, Kbps) at which data is transmitted between your computer and another device. Often used to specify the speed of data transfer over the Internet.
Drive mapping.
Assigning a drive letter to a computer drives and network drives.
Drive Bays.
Variably sized bays to accommodate disk drives, including hard drives, floppy disk drives and CD-ROM or DVD-ROM drives.
An electronic switch. Also termed a gate.
System Clock.
An electronic circuit in the computer that emits pulses at a rapid rate to establish the timing for all system operations.
Clock Speed.
A given processor clock rate measured in millions of cycles per second (megahertz, MHz).
Each single operation that a computer is capable of performing, associated with a unique number.
Instruction Set.
The collection of instructions that a CPU is designed to process.
Control Unit.
The subcomponent of the CPU that directs and coordinates all other parts of the computer system.
Machine Cycle.
The four-step processing cycle consisting of the instruction cycle (fetch and decode) and the execution cycle (execute and write-back).
ALU (Arithmetic Logic Unit).
The part of the CPU that performs arithmetic and logical operations on the numbers stored in its registers.
A temporary storage area in the CPU where data or instructions are moved so that they can be processed.
Compatible Platforms.
Computer brands or models that operate in essentially the same way, use the same software, and accept the same peripheral devices.
Downwardly Compatible.
The ability of an operating system or chip to run application software designed for earlier versions.
Data Bus.
The electronic circuitry (data lines) that connects the electronic components (mainly the processor and RAM) of a microprocesssor.
Word Size.
The number of bits the CPU can manipulate at one time, dependent on the size of the registers in the CPU and on the number of data lines in the data bus.
A technology that allows a processor to begin executing an instruction before completing the previous instruction, so instructions are worked on simultaneously.
Parallel Processing.
A technique by which two or more processors in a computer perform processing tasks simultaneously.
CISC (Complex Instruction Set Computer).
A general-purpose microprocessor chip designed to handle a wider array of instructions than a RISC (Reduced Instruction Set Computer) chip.
FPU (Floating Point Unit).
A math coprocessor that enables a computer to do math (floating point) operations faster.
Running two or more programs at the same time.
Benchmark Test.
A set of tests used to measure computer hardware or software performance.
Read-only memory, e.g. the integrated circuits that contain permanent instructions that the computer uses during the boot process.
Volatile Memory.
Memory contents that are erased when a computer is shut off.
Boot Process.
The sequence of events that occurs within a computer system between the time the user starts the computer and the time it is ready to process commands.
Setup Program.
A program that enables PC users to configure system settings. Also. a program module supplied with a software package for the purpose of installing the software on a PC.
CMOS Memory.
A type of battery-powered integrated circuit that holds semi-permanent configuration data (acronym for complementary metal oxide semiconductor). Called parameter RAM on Macintosh.
DIMM (Dual In-line Memory Module).
A small circuit board that holds RAM chips. A DIMM has a 64-bit path to the memory chips. DIMMs are newer and have larger memory capacity than do SIMMs.
Virtual memory.
A computer's use of hard disk storage to simulate RAM.
Cache Memory.
Special high-speed memory that gives the CPU more rapid access to data (also called RAM cache).
The circuitry that allows a computer to collect data (input) and the transportation of the results to display, print, or storage devices (output).
Parallel Transmission.
A method of communicating digital data in which more than one bit of data is sent at the same time.
Serial Transmission.
A method of communicating digital data in which each bit of data is sent one after the other.
SCSI (Small Computer System Interface).
An interface standard used for attaching peripheral devices, such as disk drives, printers, etc., in a chain series. Pronounced "scuzzy."
USB (Universal Serial Bus).
A port that can connect numerous devices at once, and allows connecting and disconnecting without shutting down (hot swapping).
FireWire Port.
A high-speed connection for multiple peripheral devices, enabling hot swapping and Plug and Play.
Analog Device.
A device that operates on continuously varying data, such as a dimmer switch or a watch with a sweep second hand.
Digital device.
A device that works with discrete (distinct or separate) numbers or digits. Electronic digits can be represented only as either high- powered or low-powered (+ or -) circuits.
Binary Number System.
A method for representing numbers using only two digits, 0 and 1. The decimal system uses ten digits (0, 1, 2, 3, 4, 5, 6, 7,8, and 9) and the hexadecimal system uses 16 (0 to 15).
Character Representation Code.
A series of bits that represents a letter, symbol, or numeral (also called simply "code"). These codes include ASCII, EBCDIC, ANSI, and Unicode.
ASCII (American Standard Code for Information Interchange).
A code that represents characters as a series of 1 s and Os. Most computers use ASCII code to represent text, making it possible to transfer data between computers.
Parity Bit.
An bit added to the end of a data block to allow for error checking during data transmission.


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