MICROSOFT Computer Dictionary, Fifth Edition

Microsoft Computer Dictionary, Fifth Edition

Management Information Services n. See Information Services.

management information system

n. A computer-based system for processing and organizing information so as to provide various levels of management within an organization with accurate and timely information needed for supervising activities, tracking progress, making decisions, and isolating and solving problems. Acronym: MIS.

Management Information Systems n. See Information Services.

manager

n. Any program that is designed to perform a certain set of housekeeping tasks related to computer operation, such as the maintenance of files. On the Macintosh, Manager (with a capital M) is used in the names of various separate portions of the computer’s operating system that handle input, output, and internal functions (for example, File Manager and Memory Manager).

Manchester coding

n. A method of encoding data used in communications, such as on some LANs, that combines both data and timing signals in a stream of transmitted bits. See also phase encoding.

mandatory user profile

n. A user profile that is not updated when the user logs off. It is downloaded to the user’s desktop each time the user logs on, and it is created by an administrator and assigned to one or more users to create consistent or job-specific user profiles. See also local user profile, roaming user profile, user profile.

Mandelbrot set n. See fractal.

man-in-the-middle attack

n. A form of attack in which the intruder intercepts messages between parties in a public key exchange. Each party’s messages are diverted to the intruder, who may alter them before sending them on. The parties on each end of the exchange remain unaware that their messages are being intercepted and modified. Also called: bucket brigade attack.

man-machine interface

n. The set of commands, displays, controls, and hardware devices enabling the human user and the computer system to exchange information. See also user interface.

man pages

n. 1. Online documentation for UNIX commands and programs and the UNIX library routines available for use in C programs. These documents, also found in the UNIX Programmer’s Manual, can be displayed on a user’s terminal or printed using the command man. 2. Short for manual pages. A set of help files included with a Linux distribution. Man pages may come with the Linux distribution and be installed along with the operating system or may be available from online sources.

mantissa

n. 1. In calculations that have logarithms, the positive decimal fraction of a common (base-10) logarithm. For example, the common logarithm of 16 is 1.2041; the characteristic, or wholenumber portion, of the logarithm is 1 (the logarithm of 10); and the mantissa, or fractional portion, is .2041 (the logarithm of 1.6). See also characteristic, logarithm. 2. In floating-point notation, the portion expressing the significant digits of a number. For example, the floating-point

Microsoft Computer Dictionary, Fifth Edition

representation of 640,000 is 6.4E+05. The mantissa is 6.4; the exponent (E+05) shows the power of 10 to which 6.4 is raised. Also called: significand. See also floating-point notation.

manual link

n. A link that requires you to take action to update your data after the data in the source document changes.

many-to-many relationship

n. A complex association between two sets of parameters in which many parameters of each set can relate to many others in the second set. A many-to-many relationship is most commonly used to describe an association between two tables in which one record in either table can relate to many records in the other table.

many-to-one relationship

n. 1. A server configuration in which several small servers replicate the abilities of one larger, more powerful server. See also key pair. 2. In reference to asymmetric key encryption, the idea that many individuals in possession of the public key can decrypt the digital signature of one individual in possession of the private key.

map1

n. Any representation of the structure of an object. For example, a memory map describes the layout of objects in an area of memory, and a symbol map lists the associations between symbol names and memory addresses in a program. See also image map.

map2

vb. To translate one value into another. For example, in computer graphics one might map a three-dimensional image onto a sphere. In reference to virtual memory systems, a computer might translate (map) a virtual address into a physical address. See also virtual memory.

MAPI

n. Acronym for Messaging Application Programming Interface. The Microsoft interface specification that allows different messaging and workgroup applications (including e-mail, voice mail, and fax) to work through a single client, such as the Exchange client included with Windows 95 and Windows NT. See also application programming interface.

mapped data field

n. A field that represents commonly used information, such as “First Name.” If a data source contains a “First Name” field or variation, such as “FName,” the data source field automatically maps to the corresponding mapped data field.

mapped drives

n. 1. In the Windows environment, network drives that have been assigned local drive letters and are locally accessible. 2. Under UNIX, disk drives that have been defined to the system and can be made active.

MapPoint

n. Business mapping software introduced by Microsoft as an Office-compatible product in 1999. Designed for use by business people, MapPoint consists of a database of United States maps showing detail down to the level of individual streets and demographic data broken out by state, county, zip code, and other regions. See also Office.

margin

n. In printing, those portions of a page—top, bottom, and sides—outside the main body of text.

mark

Microsoft Computer Dictionary, Fifth Edition

n. 1. In applications and data storage, a symbol or other device used to distinguish one item from others like it. 2. In digital transmission, the state of a communications line (positive or negative) corresponding to a binary 1. In asynchronous serial communications, a mark condition is the continuous transmission of binary 1s to indicate when the line is idle (not carrying information). In asynchronous error checking, setting the parity bit to 1 in each group of transmitted bits is known as mark parity. See also parity. Compare space. 3. In optical sensing, a pencil line, as on a voting form or an IQ test, that can be recognized by an optical reader.

marker

n. 1. Part of a data communications signal that enables the communications equipment to recognize the structure of the message. Examples are the start and stop bits that frame a byte in asynchronous serial communications. 2. A symbol that indicates a particular location on a display surface.

Mark I

n. 1. An electromechanical calculating machine designed in the late 1930s and early 1940s by Howard Aiken of Harvard University and built by IBM. Also called: Automatic Sequence Controlled Calculator, Harvard Mark I. 2. The first fully electronic stored-program computer, designed and built at Manchester University in England. It successfully executed its first program in June 1948. 3. The first commercial computer, which was based on the Manchester Mark I and released in 1951.

markup

n. Comments and tracked changes such as insertions, deletions, and formatting changes that you can view or print.

markup language

n. A set of codes in a text file that instructs a computer how to format the file on a printer or video display or how to index and link its contents. Examples of markup languages are Hypertext Markup Language (HTML) and Extensible Markup Language (XML), which are used in Web pages, and Standard Generalized Markup Language (SGML), which is used for typesetting and desktop publishing purposes and in electronic documents. Markup languages of this sort are designed to enable documents and other files to be platform-independent and highly portable between applications. See also HTML, SGML, XML.

marquee

n. A nonstandard HTML extension that causes scrolling text to appear as part of a Web page. Currently, marquees are viewable only with Internet Explorer. See also HTML, Internet Explorer, Web page.

marquee component

n. A region on a page that displays a horizontally scrolling text message.

mask

n. 1. A binary value used to selectively screen out or let through certain bits in a data value. Masking is performed by using a logical operator (AND, OR, XOR, or NOT) to combine the mask and the data value. For example, the mask 00111111, when used with the AND operator, removes (masks off) the two uppermost bits in a data value but does not affect the rest of the value. See the illustration. See also logical operator, mask bit. 2. In television and display technology, a thin perforated sheet of metal or a close-set series of metal strips on the surface of the screen that helps create a clear, sharp image by ensuring that the electron beam for a particular color (red, blue, or green) strikes only the phosphor it is intended to illuminate, while the phosphors for the other colors are shadowed by the mask. Three types of masks are in use: a shadow mask, with round perforations; an aperture grill, with vertical stripes; and a slot mask, with elliptical openings. See also aperture mask, shadow mask, slot mask.

Microsoft Computer Dictionary, Fifth Edition

Mask.

maskable interrupt

n. A hardware interrupt that can be temporarily disabled (masked) during periods when a program needs the full attention of the microprocessor. See also external interrupt, hardware interrupt, interrupt. Compare nonmaskable interrupt.

mask bit

n. A given bit within a binary mask whose function is to screen out or let through the corresponding bit in a data value when the mask is used in an expression with a logical operator. See also mask (definition 1).

masking

n. The process of using the mask operation to perform operations on bits, bytes, or words of data. See also mask (definition 1).

mask off

vb. To use a mask to remove bits from a byte of data. See also mask (definition 1).

massively parallel processing

n. A computer architecture in which each of a large number of processors has its own RAM, which contains a copy of the operating system, a copy of the application code, and its own part of the data, on which that processor works independently of the others. Acronym: MPP. Compare SMP.

massively parallel processor

n. A computer designed to perform massively parallel processing.

mass storage

n. A generic term for disk, tape, or optical disc storage of computer data, so called for the large masses of data that can be stored in comparison with computer memory capacity. Compare memory.

Master Boot Record

n. The first sector of the first hard disk; a physically small but critical element in the startup process on an x86-based computer. When a computer is booted, it processes a series of selftests and then reads the Master Boot Record, or MBR, into memory. The MBR contains instructions that locate the disk’s system (startup) partition, read the contents of the first sector of the system partition into memory, and then carry out the instructions contained in that sector. If the sector represents what is known as a Partition Boot Sector, the instructions found there begin the process of loading and starting the operating system. In other words, the startup process on an x86-based computer is as follows: self-test to Master Boot Record; MBR to system partition and Partition Boot Sector; Partition Boot Sector to operating system; and, finally, a computer ready to go to work. Acronym: MBR. See also Partition Boot Sector.

master file

n. In a set of database files, the file containing more or less permanent descriptive information about the principal subjects of the database, summary data, and one or more critical key fields. For example, customers’ names, account numbers, addresses, and credit terms might be stored in a master file. See also master record. Compare transaction file.

Microsoft Computer Dictionary, Fifth Edition

master key

n. The server-based component of software or data protection. In some systems, data or applications are stored on a server and must be downloaded to the local machine for use. When a client requests the data, it presents a session key. If the session key supplied matches the master key, the key server sends the requested packet. See also client (definition 3), server (definition 2).

master record

n. A record in a master file; typically, the descriptive and summary data related to the item that is the subject of the record. See also master file.

master reseller

n. A status assigned by computer equipment manufacturers to dealers and distributors who meet certain qualifications, usually related to the number of pieces the reseller expects to sell.

master/slave arrangement

n. A system in which one device, called the master, controls another device, called the slave. For example, a computer can control devices connected to it.

matching

n. The process of testing whether two data items are identical or of finding a data item that is identical to a key. See also pattern recognition.

Material Requirements Planning

n. An approach to information management in a manufacturing environment that makes use of software to help monitor and control processes related to manufacturing—for example, managing schedules and determining when and in what quantities to order materials. Acronym: MRP. Also called: Material Resource Planning. See also Enterprise Resource Planning.

math coprocessor

n. See floating-point processor.

mathematical expression

n. An expression that uses numeric values, such as integers, fixed-point numbers, and floatingpoint numbers, and operators, such as addition, subtraction, multiplication, and division. See also expression.

mathematical function

n. A function in a program that performs a set of mathematical operations on one or more values or expressions and that returns a numeric value.

mathematical model

n. The mathematical assumptions, expressions, and equations that underlie a given program. Mathematical models are used to model “real-world” physical systems such as planets in orbit around a star or resource production and consumption within a closed system.

MathML

n. Acronym for Mathematical Markup Language. An XML application for describing mathematical notation and capturing both its structure and content. The goal of MathML is to enable mathematics to be served, received, and processed on the Web, just as HTML has enabled this functionality for text.

matrix

n. An arrangement of rows and columns used for organizing related items, such as numbers, dots, spreadsheet cells, or circuit elements. Matrices are used in mathematics for manipulating

Microsoft Computer Dictionary, Fifth Edition

rectangular sets of numbers. In computing and computer applications, matrices are used for the similar purpose of arranging sets of data in table form, as in spreadsheets and lookup tables. In hardware, matrices of dots are used in creating characters on the screen as well as in print (as by dot-matrix printers). In electronics, matrices of diodes or transistors are used to create networks of logic circuits for such purposes as encoding, decoding, or converting information. See also grid.

matrix line printer n. See line printer.

MAU

n. Acronym for Multistation Access Unit. A hub device in a token-ring network that connects computers in a physical hub-and-spokes arrangement but uses the logical ring required in token ring networks. Also called: MSAU. See also hub, token-ring network.

maximize

vb. In a graphical user interface, to cause a window to expand to fill all the space available within a larger window or on the screen. See also enlarge, graphical user interface, Maximize button, window. Compare minimize, reduce.

Maximize button

n. In Windows 3.x, Windows 9x, Windows NT, and Windows 2000, a button in the upper righthand corner of a window that, when clicked, maximizes a window to fill all the space available within a larger window or on the screen. See also graphical user interface, window. Compare Minimize button, zoom box.

Maximum Transmission Unit n. See MTU.

Mb

n. See megabit.

MB

n. See megabyte.

MBONE or Mbone

n. Short for Multicast backbone. A small set of Internet sites, each of which can transmit real-time audio and video simultaneously to all the others. MBONE sites are equipped with special software to send and receive packets at high speed using the IP one-to-many multicasting protocol. The MBONE has been used for video conferencing and even for a Rolling Stones concert in 1994. See also RealAudio.

Mbps

n. Short for Mega bits per second. One million bits per second.

MBR

n. See Master Boot Record.

MC

n. See megacycle.

MC68000

n. See 68000.

MC68020

Microsoft Computer Dictionary, Fifth Edition

n. See 68020.

MC68030

n. See 68030.

MC68040

n. See 68040.

MC68881

n. See 68881.

MCF

n. See Meta-Content Format.

MCGA

n. Acronym for Multi-Color Graphics Array. An older video adapter included in the IBM PS/2 Models 25 and 30. The MCGA was capable of emulating the CGA (Color/Graphics Adapter) and provided two additional graphics modes: the first mode had 640 horizontal pixels by 480 vertical pixels with 2 colors chosen from a palette of 262,144 colors; the second had 320 horizontal pixels by 200 vertical pixels with 256 colors chosen from a palette of 262,144 colors. See also graphics mode (definition 2).

MCI

n. 1. Acronym for Media Control Interface. Part of the Windows application programming interface that enables a program to control multimedia devices. 2. A major long-distance telephone service carrier, originally Microwave Communications, Inc.

m-commerce

n. Short for Mobile commerce. M-commerce involves the use of personal digital assistants (PDAs), digital phones, and other wireless handheld devices equipped with microbrowsers for the online buying and selling of goods. M-commerce is distinguished from other electronic commerce by the level of portability. Wireless Application Protocol (WAP) standards form the foundation of m-commerce technology, which takes advantage of smart phone capabilities with e-mail, fax, Internet, and phone in one mobile unit. See also microbrowser, Wireless Application Protocol.

MCP

n. Acronym for Microsoft Certified Professional. A basic certification from Microsoft that verifies an individual’s ability to successfully implement a Microsoft product or technology as part of a solution for an organization. The MCP certification is often used as a building block for acquiring additional certifications in specialized skill areas such as databases, programming languages, and Web development.

MCSA

n. Acronym for Microsoft Certified Systems Administrator. A certification from Microsoft that verifies an individual’s ability to implement, manage, and troubleshoot existing Microsoft Windows and Windows .NET network and system environments. See also MCP.

MCSD

n. Acronym for Microsoft Certified Solution Developer. A certification from Microsoft that verifies an individual’s ability to use Microsoft development tools, technologies, and platforms to design and develop business solutions. See also MCP.

MCSE

n. Acronym for Microsoft Certified System Engineer. A certification from Microsoft that verifies an individual’s ability to analyze business requirements and then design and implement business solutions with Microsoft Windows platforms and server software. See also MCP.

Microsoft Computer Dictionary, Fifth Edition

MD2

n. A hashing algorithm that creates a 128-bit hash value used to verify data integrity. MD2 is an earlier, 8-bit version of the more common MD5. See also hashing algorithm.

MD4

n. A hashing algorithm that creates a 128-bit hash value used to verify data integrity. Like the latest version, MD5, MD4 is optimized for 32-bit machines. See also hashing algorithm.

MD5

n. An industry-standard, one-way, 128-bit hashing scheme, developed by MIT Laboratory for Computer Science and RSA Data Security, Inc., and used by various Point-to-Point Protocol (PPP) vendors for encrypted authentication. An extension of MD4, MD5 is slightly slower than the earlier version but offers improved data security. See also hashing algorithm.

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 Display Adapter or 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 MTBF.

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 mechanical and electronics to describe a field of engineering that applies mechanical, electrical, and electronic engineering concepts to product design and manufacture. A relatively new discipline, mechatronics is applicable to products in fields as diverse as medicine, robotics, manufacturing, and consumer electronics.

media

n. 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.

Microsoft Computer Dictionary, Fifth Edition

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 unshielded 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 equipment. See also coaxial cable, Ethernet (definition 1).

media stream

n. A continuous sequence of audio or audio-and-video through a network.

medium1

adj. Of or relating to the middle part of a range of possible values.

medium2

n. 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

n. See megabyte.

mega-

prefix One million (106). In computing, which is based on the binary (base-2) numbering system, megahas a literal value of 1,048,576, which is the power of 2 (220) closest to one million. Abbreviation: M.

megabit

n. Usually 1,048,576 bits (220); sometimes interpreted as 1 million bits. Abbreviation: Mb, Mbit.

megabyte

n. Usually 1,048,576 bytes (220); sometimes interpreted as 1 million bytes. Abbreviation: MB.

megacycle

n. A term for 1 million cycles—usually used to mean 1 million cycles per second. Abbreviation: MC. See also megahertz.

Microsoft Computer Dictionary, Fifth Edition

megaflops

n. See MFLOPS.

megahertz

n. A measure of frequency equivalent to 1 million cycles per second. Abbreviation: MHz.

megapel display

n. See megapixel display.

megapixel

adj. A reference to image resolution of one million pixels or more. The term is used in reference to devices such as digital cameras, scanners, and computer monitors and display adapters.

megapixel display

n. A video display capable of displaying at least 1 million pixels. For example, a video display with a screen size of 1024 horizontal pixels and 1024 vertical pixels is a megapixel display. Also called: megapel display.

Melissa

n. A macro virus that affects Word files in Microsoft Office 97 and Office 2000 and first appeared in the spring of 1999. Melissa is delivered as an attachment to an e-mail with the subject line “An Important Message From <user name>,” a message beginning “Here is that document you asked for…,” or both. When the attachment is opened, the virus propagates (if Microsoft Outlook is installed) by sending itself to the first 50 e-mail addresses in the user’s Outlook address book. On the infected machine, the virus also changes the registry, infects the Normal.dot Word template (which, in turn, infects new documents), and, in Office 2000, disables the Word macro virus warning. Although the Melissa virus does not destroy data, it can affect e-mail performance through the increased volume of messages. If an infected document is open at a time when the day of the month is the same as the minute value of the current time, the virus inserts the text “Twenty-two points, plus triple-word-score, plus fifty points for using all my letters. Game’s over. I’m outta here” at the current location of the cursor. The virus was named after an acquaintance of the hacker who developed it.

meltdown

n. 1. The complete collapse of a computer network caused by a higher level of traffic than the network can support. The term refers, by analogy, to the accidental melting down of a nuclear reactor core. 2. Colloquially, the breakdown of a person, usually in a job situation, caused by overwork, stress, or failure.

member

n. 1. In object-oriented programming, a variable or routine that is part of a class. See also C++, class. 2. A value that is part of a set data structure. See also set2 (definition 1).

membrane keyboard

n. A keyboard in which an unbroken plastic or rubber shell (a membrane) covers keys that have little or no travel (movement). Rather than use normal, full-travel keys, membrane keyboards use pressure-sensitive areas that are sometimes, but not always, defined by small bumps under the membrane.

memo field

n. A field in a database file that can contain unstructured text.

memo pad