Computer Terms

Motherboard - The main circuit board inside a computer, which contains the central processing unit, the bus, memory sockets, expansion slots, and other components. Additional boards, called daughter boards, can be plugged into the motherboard.

CPU - Central Processing Unit. The CPU controls the operation of a computer. Units within the CPU perform arithmetic and logical operations and decode and execute instructions. In microcomputers, the entire CPU is on a single chip.

RAM - Random Access Memory. The working memory of the computer. RAM is the memory used for storing data temporarily while working on it, running application programs, etc. "Random access" refers to the fact that any area of RAM can be accessed directly and immediately, in contrast to other media such as a magnetic tape where the tape must be wound to the point where the data is. RAM is called volatile memory; information in RAM will disappear if the power is switched off before it is saved to disk. There is also a form of non-volatile RAM, which must be continually energized by a battery to maintain its content. The most common form of RAM is built from semiconductor integrated circuits.

Video Card - Also called graphics adapter, display adapter, video adapter. A circuit board that enables a computer to display information on its screen. The resolution, number of colors, and refresh rate of a monitor is determined by the kind of video card used, plus the limitations of the monitor itself.

Hard Drive - Hard disk drive. A disk drive that reads from and writes to a hard disk.

Case - A box that contains the components of a computer system.

CD-ROM - Compact Disc Read-Only Memory. An optical disc that is physically the same as an audio CD, but contains computer data. Storage capacity is about 680 megabytes. CD-ROMs are interchangeable between different types of computers.

CD-RW - CD-Re-Writable. A CD-ROM that can be written, erased, and rewritten by the user. CD-RW discs usually will only play on Multi-Read CD-ROM drives; some CD players with exceptional speed may have the sensitivity to read CD-RW discs.

DVD-ROM - Digital Video Disc-Read Only Memory. A disc like a CD-ROM that has more storage (4.7 gigabytes) and can provide digital video. DVD-ROMs with 17GB storage will soon be available.

Floppy Drive - The disk drive where a floppy disk is inserted.

Keyboard - A set of keys for computer input, which resembles a typewriter keyboard, but with a few extra keys for computer commands and usually a numeric keypad added. The original typewriter keys worked mechanically to make a metal hammer with a raised, inked type character on it strike a page. On a computer keyboard, hitting on a key sends an electrical signal to a microprocessor, which sends a scan code to the computer's basic input/output system. The BIOS translates the scan code into an ASCII code that stands for a character, which is read by the operating system or program so the character appears on the screen.

Mouse - A pointing device that is used to move a cursor on the computer screen, and make various operations possible such as typing, drawing, editing text and graphics, opening and closing files, and giving other commands. The wire connecting it to the computer or keyboard looks like a mouse's tail. A mouse is moved over a flat horizontal surface, usually a rubber mouse pad, and its position is read by the computer. The original mouse has a button which the user clicks or holds down to place the cursor; now many models have more than one button.

NIC - Network Interface Card. A network adapter.

Modem - A peripheral device that connects computers to each other for sending communications via the telephone lines. The modem modulates the digital data of computers into analog signals to send over the telephone lines, then demodulates back into digital signals to be read by the computer on the other end; thus the name "modem" for modulator/demodulator. Modems are used for sending and receiving electronic mail, connecting to bulletin board systems, and surfing the Internet. There are standards to ensure that modems made by different manufacturers can communicate with each other. Modems communicating with each other must use the same speed.

Monitor - Also called a display. A device that displays text and graphics generated by a computer. Desktop monitors are usually cathode-ray tubes, and laptop monitors are usually liquid crystal display. A monitor can be monochrome (black and white) or color. Color monitors may show either digital or analog color.