Username: Matt Clements Book: Microsoft® Computer Dictionary . No part of any chapter or book may be reproduced or
`transmitted in any form by any means without the prior written permission for reprints and excerpts from the publisher of
`the book or chapter. Redistribution or other use that violates the fair use privilege under U.S. copyright laws (see 17
`USC1OT) or that otherwise violates these Terms of Service is strictly prohibited. Violators will be prosecuted to the full
`extent of U.S. Federal and Massachusetts laws.
`
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`alert n. 1. In many operating systems with GUls (graphical user interfaces), an audible or visual
`alarm that signals an error or represents a warning of some sort. See also alert box. 2. In program-
`ming, an asynchronous notification sent by one thread to another. The alert interrupts the recipient
`thread at defined points in its execution and causes it to execute an asynchronous procedure call.
`See also asynchronous procedure call, thread (definition 1).
`
`alert box n. An on-screen box in a GUI (graphical user interface) that is used to deliver a message
`or warning. Compare dialog box.
`
`Alerter service n. A service used by the server and other services to notify selected users and
`computers of administrative alerts that occur on a computer. The Alerter service requires the Mes-
`senger service. See also administrative alerts, Messenger service, service.
`
`ALGOL n. Acronym for Algorithmic Language. The first structured procedural programming lan-
`guage, developed in the late 19503 and once widely used in Europe.
`
`algorithm n. A finite sequence of steps for solving a logical or mathematical problem or performing
`a task.
`
`algorithmic language n. A programming language, such as Ada, Basic, C, or Pascal, that uses
`algorithms for problem solving.
`
`Algorithmic Language n. See ALGOL.
`
`alias n. 1. An alternative label for some object, such as a file or data collection. 2. A name used to
`direct e—mail messages to a person or group of people on a network. 3. A false signal that results
`from the digitization of an analog audio sample.
`
`In computer graphics, the jagged appearance of curves or diagonal lines on a display
`aliasing n.
`screen, which is caused by low screen resolution. See the illustration.
`
`Allasmg. The lower resolution of the image on the right reveals the aliasing effect.
`
`aliasing bug n. A class of subtle programming errors that can arise in code that performs dynamic
`allocation. If several pointers address the same chunk of storage, the program may free the storage
`using one of the pointers but then attempt to use another one (an alias), which would no longer be
`pointing to the desired data. This bug is avoidable by the use of allocation strategies that never use
`more than one copy of a pointer to allocated core memory, or by the use of higher-level languages,
`such as LISP, which employ a garbage collection feature. Also called stale pointer bug. See also
`alias, dynamic allocation, garbage collection.
`
`align vb. 1. In an application such as a word processor, to position lines of type relative to some
`point, such as the page margin. The most common types of alignment are left- and right-aligned
`and centered. See the illustration. 2. To adjust some device to position it within specified tolerances,
`such as the readlwrite head relative to a track on a disk. 3. In data handling, to store multiple-byte
`data units so that the respective bytes fall in corresponding locations of memory.
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`Username: Matt Clements Book: Microsoft® Computer Dictionary . No part of any chapter or book may be reproduced or
`transmitted in any form by any means without the prior written permission for reprints and excerpts from the publisher of
`the book or chapter. Redistribution or other use that violates the fair use privilege under U.S. copyright laws (see 17
`USCIOT) or that otherwise violates these Terms of Service is strictly prohibited. Violators will be prosecuted to the full
`extent of U.S. Federal and Massachusetts laws.
`
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`MDA n. Acronym for Monochrome Display Adapter. The video adapter introduced with the earliest
`model of the IBM PC in 1981. MDA was capable of only one video mode: a character mode with 25
`lines of 80 characters each, with underlining, blinking, and high—intensity characters. IBM did not
`use the name Monochrome Dr'splayAdapleror the acronym MDA.
`
`MDI n. Acronym for multiple-document interface. A user interface in an application that allows the
`user to have more than one document open at the same time. See also user interface.
`
`MDIS n. See Metadata Interchange Specification.
`mean time between failures n. See NITBF.
`
`mean time to repair n. See MTTR.
`
`mechanical mouse n. A type of mouse in which the motion of a ball on the bottom of the mouse is
`translated into directional signals. As the user moves the mouse, the ball rolls, turning a pair of
`wheels mounted at right angles inside the mouse that have conductive markings on their surfaces.
`Because the markings permit an electric current to flow, a set of conductive brushes that ride on the
`surface of the conductive wheels can detect these conductive markings. The electronics in the
`mouse translate these electrical movement signals into mouse-movement information that can be
`used by the computer. See also mouse, trackball. Compare optical mouse, optomechanical mouse.
`
`mechatronics n. A term derived from the words mecham'caland electronics to describe a field of
`
`engineering that applies mechanical, electrical, and electronic engineering concepts to product de-
`sign and manufacture. A relatively new discipline, mechatronics is applicable to products in fields
`as diverse as medicine, robotics, manufacturing, and consumer electronics.
`
`media 17. The physical material, such as paper, disk, and tape, used for storing computer-based
`information. Media is plural; medium is singular.
`
`Media Access Control n. See MAC.
`
`Media Control Interface n. See MCI (definition 1).
`
`media conversion n. Transferring data from one storage medium to another—for example, from
`disk to tape.
`
`media eraser n. A device that removes or obliterates data from a storage medium on a wholesale
`basis, usually by writing meaningless data (such as zeros) over it. See also bulk eraser.
`
`media filter n. 1. A device used with local area networks (LANs) as an adapter between two different
`types of media. For example, an RJ-45 connector might be used between coaxial cable and un-
`shielded twisted pair (UTP) cables. Media filters are similar in function to transceivers. As with many
`components to LANs, manufacturers often choose different names for similar products, so a LAN
`expert is needed to decide which media filters are required for a particular LAN. See also coaxial
`cable, connector (definition ‘1), LAN, transceiver, UTP. 2. A device added to data networks to filter
`out electronic noise from the environment. For example, a media filter might be added to an Ethernet
`network based on coaxial cabling to prevent data loss from interference by nearby electronic equip-
`ment. See also coaxial cable, Ethernet (definition 1).
`
`media stream n. A continuous sequence of audio or audio-and-video through a network.
`
`medium1 aajf. Of or relating to the middle part of a range of possible values.
`
`medium2 :7. A substance in which signals can be transmitted, such as a wire or fiber-optic cable.
`See media.
`
`medium model n. A memory model of the Intel 80x86 processor family. The medium model allows
`only 64 kilobytes for data but generally up to 1 megabyte for code. See also memory model.
`
`medium-scale integration n. A concentration of circuit elements in the hundreds on a single chip.
`Acronym: MSI. See also integrated circuit.
`
`meg I). See megabyte.
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