Tom Allen Computer Science Department Trinity University

Hardware: the physical devices and components associated with the computer.

Bit: a unit of information storage capacity in computer memory; it is sufficient to store either a 0 or a 1. It is short for Binary Digit.

Byte: the amount of space necessary to store one character; usually eight bits.

ASCII: American Standard Code for Information Interchange. A standard for defining codes for information exchange between equipment produced by different manufacturers. (collating sequence)

Mouse: a surface device which an operator can manipulate in order to control a pointer image on the computer system.

Monitor: a hardware device used to project a visual image into the processing of a computer system. It is the most common computer output device.

Keyboard: a most common hardware device used to input information and commands into a computer system.

Mother Board: a large circuit board into which can be plugged a number of smaller boards, or circuit elements. This board becomes the backbone of a computer system.

Microprocessor: a single semiconductor chip or a small number of chips that contains the arithmetic and control logic circuitry necessary to perform the operations of a computer.

CPU: Central Processing Unit. The control circuitry necessary to perform the operations of a computer.

IC Chip: Integrated Circuit Chip. A complex electronic circuit fabricated on a simple piece of material, usually a silicon.

RAM: Random Access Memory. A memory chip used for the main memory of a microcomputer. Application software will both store and retrieve information from this type of chip.

Floppy Drive: a computer storage read/write device, usually of minimal capacity, which accepts multiple surfaces. Data on these surfaces may be randomly accessed. The high density, double sided floppy disks of today hold 1.4 MB of data.

Hard Drive: a computer storage read/write device, usually of substantial capacity, which has fixed/permanent surfaces. Data on these surfaces may be randomly accessed. Hard drives hold as little as 10 MB and as much as several GB.

Tape Drive: a computer storage read/write device, usually of substantial capacity, which has one surface. Data on this surfaces must be sequentially accessed. It is used primarily for backup purposes. Tape drive access is slow!

CD Rom Drive: (DVD) a computer storage read and/or read/write device, always of substantial capacity, which has one surface. Data on this surface may be randomly accessed. The optical disk containing digitized information uses the same technology as the musical CD. Most of the compact disks used by computers are 4.7 inches and hold as much as 780 MB. The CD drive uses laser technology to read and write to the drive.

Modem: a data communication device that enables computers to communicate via telephone lines. The term modem was constructed from the terms MOdulate and DEModulate. Modulation translates digital data into analog data. Analog data can be transferred along the phone line. Demodulation translates analog data into digital data. Single phone line modems speeds range from 1200 baud to 33,600 baud.

Format Disk: the process of laying out a structure on the disk that will enable the disk to receive information. IBM PC's use a different disk format from either the Macintosh or UNIX systems. IBM PC, Macintosh, and UNIX disk formatting divides the disk into sectors, tracks, and blocks.

Track: ring-shaped portion of a floppy/hard disk surface. Sector: pie-shaped portion of a floppy/hard disk surface.

Block: rectangular-shaped portion within one track of one sector of a floppy/hard disk surface.

Input Devices: those devices that provide input to the computer. Examples of input devices would be keyboard, light pen, graphics tablet, bar code reader, mouse, scanner, digital camera, floppy drive, hard drive, CD rom drive, zip drive, electronic keyboard (music), microphone, A to D (analog to digital) devices/sensors, touch screen monitor, etc.

Output Devices: those devices that receive output from the computer. Examples of output devices would be traditional monitor, floppy drive, hard drive, CD rom drive, zip drive, speakers, printers, A to D (analog to digital) devices/sensors, touch screen monitor, photo maker, transparency maker, etc.

Kilobyte: (~ a thousand bytes) MB: Megabyte. (~ a million bytes) GB: Gigabyte. (~ a billion bytes)