Magnetic-ink character recognition. See MICK.

Magnetic printer. A printer that projects a selected pattern of charged particles onto a drum that is then transferred onto paper. Also called an ion printer.

Magnetic tape. A tape, similar to audiotape, that is coated with a film on which data can be magnetically recorded.

Mainframe. A class of computer providing large storage capacity, high-speed processing, and complex data-handling capabilities.

Management information system (MIS). A system that gathers, condenses, and filters data until they become information, then makes it available on time, and in a useful form, for use in decision making at various levels of management within an organization.

Mapping. A term that programmers use to describe the correspondence between the logical and the physical structure of a file. For example, if a physical record and a logical record happen to be equal in size, there is said to be one-to-one mapping.

Mask. In integrated-circuit design, a glass photographic plate that contains the circuit patterns used in fabricating a chip.

Mass storage. The storage of mass data. Commonly used to replace the term auxiliary storage; includes storing data on disks, tapes, and drums.

Master file. A type of file that can be thought of as a relatively permanent collection of records.

Megabyte (MB). A unit of measure that is the equivalent of 2-°, or 1,048,576, bytes.

Megahertz (MHz). A term used in computers and communication as a unit of frequency. It means million cycles per second. One megahertz = (MHz) 1.000,000 hertz.

Memory. The component of a computer system that stores programs and data while waiting to be processed by the CPU. Also called primary storage.

Memory card. A credit-card-sized removable card based on a chip technology called flash EEPROM (electrically erasable programmable read-only memory). This type of chip is useful in applications that need a rewriteable medium that does not require power to store the data. Like floppy disks, memory cards can store data and programs, are erasable, and can be exchanged among computers that have memory card slots.

Menu. A list of options from which a user must make a choice so that processing can continue.

Menu-driven interface. A technique for getting the user to make choices between several different options.

Metaphor. In software development, the use of words or pictures to suggest a resemblance. For example, the Apple Macintosh uses a desktop metaphor with its icons for paper, folders, files, waste-baskets, and so on.

Metropolitan-area network (MAN). A network that provide communications across and among major metropolitan areas. Public-safety agencies, such as police and fire departments, and dispatch-oriented companies, like Federal Express, operate and maintain their own private networks.

MICR. An acronym for magnetic-ink character recognition. Devices that are capable of recognizing patterns written or printed in magnetic ink. Used primarily by the banking industry on checks.

Micro. (1) In precise measurement, a prefix meaning one millionth. (2) In inexact measurement, a prefix meaning small. (3) Short for microcomputer.

Micro Channel. A hardware bus with a 32-bit data path used in some IBM PS/x computers. It is a trademark of IBM.

Microcomputer. A computer system based on a single-chip microprocessor as the central processing unit.

Microelectronics. The electronic logic represented as microscopic circuits on a chip.

Microfiche. A 4- by 6-inch sheet of photo film used to store images of documents in miniature.

Microfilm. A roll of photo film used to store images of documents in miniature.

Micron. A unit of measure equivalent to one-millionth (1/1,000,000) of a meter.

Microprocessor. The central processing unit (CPU) implemented on an integrated-circuit chip or set of chips.

Microprogram. The lowest level of software instructions that operates directly on the hardware circuitry of a computer.

Microsecond. A measure of time equivalent to one-millionth (1/1,000,000) of a second.

Millisecond. A measure of time equivalent to one-thousandth (1/1000) of a second.

Minicomputer. A type of medi-umsized computer introduced in the 1960s that provides lower-cost processing and storage capacities than the larger main-frame computers.

MIPS. An acronym for million instructions per second. Most often used as a unit of measure for comparing the processing speed of different computers.

Modeling. A partial simulation of real or possible situations or conditions.

Modem Short for modulator demodulator. A device that changes digital computer signals into analog computer signals for transmission over telephone lines and, in reverse, transforms analog signals into digital signals.

Modulation. Controlling a communication signal so that it contains information in the necessary format for transmission.

Modular conversion method. When changing from one computer system or method of operation to another, the system or method is divided into modules. Once a module is converted and running smoothly. the next module is converted, and so on.

Module. A set of programming instructions that can be tested and verified independently of its use in a larger program.

Monitor. A television receiver or CRT used for computer output display.

Mother board. A fiberglass circuit board that contains sockets into which chips can be plugged and a set of tracks (printed on the circuit board) that connects the various chips.

Mouse. A device used to position the cursor on a display screen in lieu of cursor control keys. A mouse also has buttons for selecting options.

Multimedia. The combination of text with dynamic data types such as sound, animation, and video.

Multimedia extensions. Time-based synchronizing software in an operating system for managing the coordination of video, sound, and animation.

Multiplexer. A device that allows several communication signals to share the same channel concurrently.

Multiprocessing. A computer system that uses two or more processors that share memory and input and output devices.

Multiprogramming. A computer system in which two or more

programs are executed concurrently by one computer. In effect, the programs take turns running, usually giving the user the illusion that he or she is the only user of the system.

Multitasking. A technique for concurrently executing tasks, or basic units of work performed by a program, on the same computer system. It is similar to multiprogramming, except the processor may be working on several portions of a program instead of several programs.

Multiuser. Systems that allow several users to share a computer's processor, memory, and mass storage simultaneously. Often characterized by systems with several terminals connected to a single central processor. Musical instrument digital interface (MIDI). A technology that interconnects electronic music instruments and computers. The information passed between MIDI devices is not sound, but a condensed description of the composition (e.g.. what notes were played, when, and with what nuance). On playback. MIDI controls the creation of sound on a synthesizer.

N

Nanosecond. A measure of time equivalent to one-billionth (I( 1,000,000,000) of a second.

Natural-language. Languages, such as English, used by humans that develop over time through usage. (See an Artificial language).

Natural-language interface. An interface that allows the user to input simple English or other natural-language phrases in lieu of complex computer commands.

Natural-language processing. Processing that translates and responds to commands that are given to a program in a natural language such as English. (See also Artificial language).

Network. Two or more communicating devices that are connected to form a system.

Network model. A technique used in database systems to store data by combining records with a linked list of pointers.

Network services. Communication functions provided by an operating system. Examples include tile-sharing, print-sharing, and electronic mail.

Neural network. A computer that has a memory that is modeled on the human brain. The memory consists of thousands of interconnected "neurons" that receive input from their neighboring neurons. They can perform very simple processing based on patterns of input and then produce results by sending their output back to neighboring neurons.

Node. The term for a device, such as a terminal, computer, or disk drive, connected to a communication network. (See also Topology).

Noise. In communications, an unwanted signal that was not part of the original transmission.

Nonimpact printer. A printer that prints without a striking mechanism impacting a ribbon. Examples include thermal, thermal transfer, electrostatic, inkjet, and laser printers.

Nonprocedural language. A programming language in which a problem is defined in terms of the results desired instead of the steps necessary to solve a problem. (See also Procedure-oriented language).

Nonvolatile storage. Memory devices, such as ROMs, magnetic tape, and magnetic disk, that can retain data when electric power is shut off. (See also Volatile storage).

Notepad. A grid of wires behind a liquid-crystal display screen combined with an electronic pen (often called a stylus). As the tip of the pen nears the screen, the location of the pen is determined by which wires in the grid detect the pen. Software can then interpret the movement and meaning of the pen strokes.

О

Object. A module that contains both data and instructions and can perform specific tasks. In software engineering, an object is an instance of a class or a logical grouping of objects.

Object code. Output from a compiler or an assembler that is linked with another code to produce executable machine-language code.

Object environment. A development environment that exploits the availability of prefabricated software components called objects. In these environments, predesigned objects can be easily combined and modified, in many different ways, to produce a new application.

Object model. In database systems, data and instructions are combined into objects - modules that perform specific tasks when they are sent an appropriate message.

Object-oriented programming. A technique in which the programmer breaks the problem into modules called objects, which contain both data and instructions and can perform specific tasks. The programmer then organizes the program around the collection of objects.

Date: 2016-01-03; view: 852