Barrons Publishing Dictionary of Computer and Internet Terms 10th

menu bar a horizontal menu across the top of the screen or window. Depending on the software, the items in the menu bar are chosen by clicking on them with a mouse, or by typing the first letter of each item, or possibly by typing the first letter while holding down Alt. Usually each item is a further menu. For an illustration, see MENU.

merge to insert data (e.g., names and addresses) from one file into a document that resides in another file (e.g., the text of a form letter).

merge sort an algorithm for sorting data (see SORT). Merge sort takes advantage of the fact that it is easy to combine two lists that are already sorted; just keep looking at the first element of each list and taking whichever element comes first. For example, to combine the lists

do the following: Compare Adams to Bush; take Adams. Then compare Buchanan to Bush and take Buchanan. Then compare Lincoln to Bush and take Bush, and so on. This will give you a list of all six names in alphabetical order.

To perform a complete merge sort, first divide your data into several small sorted lists. These can be sorted with some other sorting algorithm; or they can be two-element lists which are sorted by swapping the two elements where needed; or they can even be one-element lists, which do not need sorting. Then combine these lists, two at a time, until they all have been put together into a single sorted list.

A big advantage of merge sort is that you never need to see more than the first element of any list. Thus, merge sort can take its data from tapes or from linked lists, which cannot easily be sorted by any other algorithm. See LINKED LIST; SEQUENTIAL-ACCESS DEVICE.

mesh network a network with multiple paths connecting nodes. Devices on the network cooperate to determine routing of messages. It can function when a node fails by rerouting messages along paths that bypass the failed node. The Internet is one example.

message board a web page, NEWSGROUP, or dial-up computer system where users can post messages and reply to messages posted by others. Messages are usually public and visible to all users. Most bulletin boards associate replies with the original messages, creating threads. See also

FLAME; NEWSGROUP; POST; THREAD.

message box a small window that appears to present information to the user (Figure 168). When the user acknowledges reading the message by pressing a mouse button, the message box disappears.

message sending one way of describing object-oriented programming: objects receive “messages,” which are calls to procedures associated with them. See OBJECT-ORIENTED PROGRAMMING.

FIGURE 168. Message box

meta tag a piece of information added to a WEB PAGE for the benefit of indexers, SEARCH ENGINEs, web page creation software, or other purposes. Meta tags are not displayed when the page is viewed.

Most meta tags consist of a name and a content field. Some names are widely recognized. Here are some examples:

<meta name=”author” content=”Catherine Anne Covington”> <meta name=”keywords” content=”oranges, apples, lemons”> <meta name=”robots” content=”noindex, nofollow”>

The first identifies the author as Catherine Anne Covington; the second asks search engines to index the page under oranges, apples, and lemons; and the third asks search engines not to index the page at all, nor follow its links.

It is entirely up to a search engine to decide whether or not to comply with these requests. Also, meta tags are often used deceptively to bring in additional visitors to a site by making it come up when they search for something else. In a few extreme cases, pornography sites have been known to put an entire dictionary of the English language in the keywords meta tag.

Another type of meta tag adds information to the header sent with the HTTP file; this information helps control the browser. For example,

<meta http-equiv=”charset” content=”iso-8859-1”>

tells the browser to use the ISO-8859-1 character set, and

<meta http-equiv=”Refresh” content=”15”> <meta http-equiv=”Refresh” content=”15;

URL=http://www.xyz.org”>

say, respectively, to refresh (reload) the web page after 15 seconds and to jump to www.xyz.org after 15 seconds.

metacrawler a program that submits search queries to the major Internet indexes (such as Google, Yahoo, or Lycos) and creates a summary of the results, thus giving the searcher the benefit of using all the SEARCH ENGINEs simultaneously.

metadata information about information, such as information about the origin, format, or ownership of a data file.

metafile a file format that provides a common ground between two or more proprietary formats, and thus a translation path from one piece of software to another. For example, a Windows Metafile (.wmf) is a vectorbased drawing format that is recognized by most drawing, page-layout, and word-processing programs. See also CGM.

metal see BARE METAL.

meta language any language used to describe another language. For example, Backus-Naur Form can be used as a metalanguage to describe the syntax of programming languages. Lisp and Prolog have the interesting property that the programs can read and modify themselves, so these programming languages can be put to practical use as metalanguages for themselves. See BACKUS-NAUR FORM; LISP; PROLOG.

method (in object-oriented programming) a procedure associated with an object type. See OBJECT-ORIENTED PROGRAMMING.

metric prefixes the prefixes used in the metric system to denote multiplication of units, such as kilo- meaning “thousand.” The complete set is shown in Table 10.

When measuring computer memory or disk capacity, kilo-, mega-, giga-, and tera- often stand for powers of 1024 (= 210) rather than powers of 1000; those are the alternative values shown in the table. Even more confusingly, mega- occasionally means 1000 × 1024 = 1,024,000.

In 1998, the International Electrotechnical Commission (IEC) proposed the “binary” metric prefixes kibi-, mebi-, gibi-, and tebi- to be used in place of kilo-, mega-, giga-, and tera- where powers of 1024 rather than powers of 1000 are meant.

In Greek, kilo-, mega-, giga-, and tera- mean, respectively, “thousand,” “big,” “giant,” and “monster.”

mezzanine bus a special bus that connects the CPU to some of the faster peripherals, such as memory modules, and is separate from the slower bus used for slower peripherals. See BUS.

MFP (Multi Function Printer) a printer that also performs other functions such as faxing and scanning.

MHz see MEGAHERTZ.

MIB (describing items for sale) mint in box (i.e., new and never unpacked). See also EBAY; NRFB.

micro- metric prefix meaning ÷1,000,000 (one millionth). For example, a microsecond is one millionth of a second (0.000001 second), and a microfarad is one millionth of a farad. Micro- is derived from the Greek word for “small.” See METRIC PREFIXES.

microblogging publishing short descriptions of your current activity to a blog or web site designed for microblogging, such as Twitter, often from a phone or other mobile device. Status and mood updates on web sites such as Facebook and LiveJournal can be considered a form of microblogging.

microbrowser a web browser using less memory than a conventional browser so it can be used on a small device such as a palmtop.

microcomputer a computer whose CPU consists of a single integrated circuit known as a microprocessor. Commonly, a microcomputer is used by only one person at a time. All home computers are microcomputers. See

INTEGRATED CIRCUIT; MICROPROCESSOR.

microcontroller a microprocessor designed specifically for controlling equipment. Microcontrollers usually contain some memory and input-out- put circuitry on the same chip with the microprocessor. This enables the microcontroller to work as a self-contained unit. Microcontrollers are used in consumer products such as telephones, automobiles, and microwave ovens, as well as in industrial equipment. See also EMBEDDED SYSTEM.

Microdrive see COMPACTFLASH.

microprocessor an integrated circuit containing the entire CPU of a computer, all on one silicon chip, so that only the memory and input-output devices need to be added. The first popular microprocessor, the Intel 8080, came out in 1973 and cost approximately $400.

Microprocessors are commonly described as 16-bit, 32-bit, or the like. The number can refer either to the number of bits in each internal

data register, or to the number of bits on the data bus (see BUS); these two numbers are usually the same. Other things being equal, larger registers and a larger bus enable the processor to do its work faster.

Clock speed is also important. The clock is the oscillator that causes the microprocessor to proceed from one step to the next in executing instructions. (Each machine instruction takes several clock cycles.) Clock speed is measured in megahertz (MHz) or gigahertz (GHz): 1 MHz is 1 million cycles per second, and 1 GHz = 1000 MHz. Higher clock speeds result in faster computation, but only if exactly the same machine instructions are being executed; it is misleading to compare the clock speeds of processors of different types. It is even possible for two microprocessors with the same instruction set and clock speed to perform computations at different rates because of differences in internal design. A 100-MHz Pentium II, for example, is faster than a 100-MHz Pentium.

Microsoft the world’s leading software-producing company, headquartered in Redmond, Washington, and founded by Bill Gates and Paul Allen in 1975 when they wrote a version of BASIC for an early hobbyist microcomputer, the Altair. In the late 1970s the company grew as it sold versions of BASIC to other computer makers, but it was still fairly small when it was approached by IBM to design the operating system for the IBM PC (released in 1981).

This operating system (known as PC-DOS, MS-DOS, or simply DOS) became a huge seller, since almost all PC and PC clones used it. In 1990 Microsoft released version 3.0 of Windows, providing a graphical user interface for the PC. Updated versions of Windows continue to be the most common operating system on the PC (see WINDOWS).

Microsoft is also a big seller of applications software for both PCs and Macintoshes. The suite Microsoft Office includes the word processing program Microsoft Word, the spreadsheet Excel, the database program Access, and the presentation program Powerpoint. In 1991 Microsoft introduced Visual Basic, an advanced version of BASIC that allows the programmer to take advantage of the graphical environment of Windows. It now provides development environments for other languages in the Visual Studio series. Other products include the Microsoft Network Online service, the web browser Internet Explorer, and X-box game machines.

For further information about Microsoft and its products, see www.microsoft.com.

Microsoft antitrust charges a series of official accusations that Microsoft has violated U.S. antitrust laws (laws that prohibit businesses from monopolizing a market or conspiring to stifle competition).

In 1994, while under investigation by the U.S. Department of Justice, Microsoft accepted a consent decree in which it promised to change some of its licensing practices. For example, prior to 1994, Microsoft gave computer manufacturers a discount on Windows if the manufacturers paid Microsoft a fee for every computer made, regardless of the oper-

ating system installed on it. In effect, this amounted to requiring them to license a Microsoft operating system for every computer.

In 1998, the U.S. Department of Justice filed a broad antitrust case against Microsoft. Among other accusations, they charged that Microsoft violated antitrust laws by including its Internet Explorer browser free with Windows, because this killed off the market for other browsers (e.g., Netscape) that were available commercially. In 2000, Judge Thomas Penfield Jackson ruled that Microsoft had violated the Sherman Antitrust Act, and ordered that the company be broken up. In June 2001, an appeals court affirmed that Microsoft was guilty of monopolizing, but they vacated the order that the company be broken up and instead sent the case back to a different federal judge. The company and the U.S. Justice Department reached a negotiated settlement in November 2001. In the settlement, Microsoft agreed not to retaliate against hardware makers that worked with other software makers, and Microsoft’s behavior would be subject to monitoring. Some states felt that the settlement with the Justice Department was too lenient to Microsoft, but in November 2002 the court approved the settlement with minor modifications.

Microsoft has also settled private antitrust suits with some of its competitors.

The case has raised concerns because the main U.S. antitrust statute (Section 2 of the Sherman Antitrust Act) is so vague that it does not specify exactly which behavior is illegal. Some feel that Microsoft is being punished for technological innovation and financial success.

Microsoft has also been fined by the European Union for antitrust violations and it is still under investigation for further antitrust charges in Europe.

Microsoft Windows see WINDOWS.

middleware

1.in a three-tier system, the system that is between the user interface and the database access software. See THREE-TIER ARCHITECTURE.

2.software that occupies a middle position between application software and the operating system, so that programs written for the compatible middleware can run under different operating systems without change. Examples of middleware include web browsers and well-stan- dardized programming languages (such as FORTRAN and Java). Because of middleware, programs and web pages can be written so that they run identically on completely different computers.

MIDI (Musical Instrument Digital Interface) a standard way for communicating information about music between different electronic devices, such as computers and sound synthesizers.

MIDI comprises two things: an electrical connection between musical instruments and computers, and a file format for representing musical sounds. MIDI files are more like musical scores than digitized audio; they represent notes and instrumentation, not sound waves, and the com-

puter must “play” them like a musician. Thus, MIDI files are much more compact than WAVE FILEs.

.mil a suffix indicating that a web or e-mail address belongs to a military site in the United States. Along with .com, .edu, .gov, .int, .net, and .org, this is one of the original set of Internet top-level domains. Contrast

.COM. See also ICANN; TLD.

millennium bug a software defect reflecting the Year 2000 Problem. See

YEAR 2000 PROBLEM.

milli- metric prefix meaning ÷1000 (one thousandth). For example, one millisecond is one thousandth of a second (0.001 second), and a millimeter is one thousandth of a meter. Milli- is derived from the Latin word for “thousandth.” See METRIC PREFIXES.

MIME (Multipurpose Internet Mail Extensions) a standard proposed by N. Borenstein and N. Freed for including material other than ASCII text in e-mail messages. MIME messages can be recognized by the “ContentType” declaration in the header, and the range of content types is potentially unlimited. Most e-mail software now supports MIME encoding.

See also CGI.

mind virus see MEME.

mini-CD, mini-DVD a CD or DVD that is 8 cm in diameter (about 3 inches) instead of the usual 12 cm (43⁄4 inches).

minicomputer a computer intermediate in size between a mainframe computer and a microcomputer; two classic examples were the Digital Equipment Corporation VAX and the IBM AS/400. A minicomputer typically occupied a large area within a room and supported 10 to 100 users at a time. In recent years minicomputers have been replaced by networks of microcomputers. Contrast MAINFRAME COMPUTER; PERSONAL COMPUTER.

minimize to make a window as small as possible; usually this means it becomes an icon rather than a window. In Windows minimized icons go to the taskbar at the bottom of the screen.

To minimize a window, click on the minimize button (see WINDOW). This is a handy way to get one piece of software out of the way temporarily while you turn your attention to something else. You can then RESTORE the window when you want to resume working with it.

Caution: the minimized program is still taking up memory and you’ll find that graphics intensive programs (such as paint programs) need all the memory you can give them. You should CLOSE all minimized programs before launching a program that needs lots of memory. Some utilities can run minimized in the background (e.g., print spoolers). See also

LAUNCH; MAXIMIZE; RESTORE.

mint (describing items for sale) perfectly preserved, in new condition.

minty (describing items for sale) almost, but not quite, MINT—a vague term that encourages optimism but makes no precise claims.

MIPS (Million Instructions Per Second) a measurement of the speed with which computer programs are run. Because different instructions take different amounts of time, speed measured in MIPS depends on the exact program that the computer is running. For this reason, speed tests are usually done with standard programs such as Whetstone and Dhrystone.

Another problem is that equivalent programs take different numbers of instructions on different CPUs. To compare different computers meaningfully, it is common practice to calculate MIPS using the number of instructions that a program would require on a VAX rather than on the computer actually being tested. This way, equivalent programs are always viewed as having the same number of instructions and the speed of the computer under test is the only variable.

mirror

1.to flip an image so that the resulting image is a mirror image of the original.

2.to reproduce the entire contents of an FTP or WEB SITE so that the same files are available from more than one location.

3.to maintain an extra copy of a disk drive on a second disk drive automatically. See RAID.

FIGURE 169. Mirror, definition 1

mirroring the practice of maintaining a copy of data that is automatically kept up to date. For an example see RAID.

MIS see MANAGEMENT INFORMATION SYSTEMS.

misfeature (slang) an ill-conceived feature; a feature with unforeseen and unfortunate effects. For example, the choice of / as the option character in DOS 1.0 was a misfeature because it made it impossible to use / as the directory separator when DOS 2.0 introduced directories. As a result, DOS and Windows use \ where UNIX uses /, to the annoyance of programmers everywhere.

miter to cut at an angle. A way of specifying how lines should intersect; mitered joints come to neat points. If intersecting lines are not properly mitered, there are ugly gaps at the intersection, or the square endpoints of the lines overlap.

Most drawing programs let you set the miter limit; the threshold at which the computer bevels a sharp angle when two lines have a narrow angle of intersection. This prevents the pointed joint from extending way past the end of the line.

FIGURE 170. Mitered vs. unmitered joint

mixed case type set with normal capitalization, neither all caps nor all lowercase.

mixed-signal handling both ANALOG and DIGITAL signals. For example, a sound card is a mixed-signal device.

mixer a software control that determines the relative loudness of various kinds of sound produced by a SOUND CARD, such as MIDI music, wave file playback, and synthesized speech.

MMO (massive multiplayer online) a term describing game software that lets hundreds of users participate simultaneously. MMO is usually prefixed to another abbreviation to describe the type of game more precisely. For example, a MMORPG is a massive multiplayer online roleplaying game, such as World of Warcraft. See ROLE-PLAYING GAME.

MMORPG abbreviation for massive multiplayer online role-playing game. See MMO.

MMX (multimedia extensions) a set of additional instructions added to the later models of the Pentium microprocessor and its successors to support high-speed processing of animation and sound. The MMX instructions support a limited form of vector processing. See

mnemonic a symbol or expression that helps you remember something. For example, the expression “Spring forward, fall back” helps you remember which way to adjust your clocks in the spring and fall for daylight saving time.

A mnemonic variable name is a variable name that helps the programmer remember what the variable means. For example, in a payroll program the variable to represent the hours worked could be named X312W17HK, but it would be much better to give it a mnemonic name such as HOURS.

MO (mega-octet) French abbreviation for MEGABYTE.

mobo (slang) motherboard.

mod

1.abbreviation for modulo, used to refer to the remainder in integer division. For example, in Pascal, the expression 24 mod 7 has the value 3, since 3 is the remainder when 24 is divided by 7. In C, C++, C#, and Java, this operation is symbolized by %.

2.abbreviation for modification (a change to a piece of hardware or software).

modal dialog box a dialog box that requires an immediate response from the user; other windows cannot be used until the modal dialog box has been dealt with. Modal dialog boxes generally warn of problems such as running out of printer paper or losing a network connection. See DIALOG BOX.

mode the state that a piece of hardware or software is in, defining the way it can be used.

modem (modulator-demodulator) a device that encodes data for transmission over a particular medium, such as telephone lines, coaxial cables, fiber optics, or microwaves.

modifier key a key that changes or extends the meaning of a keyboard key. Examples of modifier keys are Shift, CTRL, and ALT.

Modula-2 a programming language developed by Niklaus Wirth in the late 1970s as a replacement for Pascal, which Wirth had developed some 10 years earlier. As its name suggests, Modula-2 is designed to encourage modularity (see STRUCTURED PROGRAMMING). Modula-2 is very similar to the extended versions of Pascal that most compilers now implement.

module a part of a larger system. A module in a computer program is a part of the program that is written and tested separately and then is combined with other modules to form the complete program. See TOP-DOWN PRO-

GRAMMING.

moiré an unintended and distracting pattern that occurs when two or more halftone screens are overprinted at the wrong angle. See Figure 171.

FIGURE 171. Moiré

monadic operation an operation on one piece of data. For example, negation (finding the negative of a number) is an operation that requires only one operand and is therefore monadic. Addition is not monadic because it requires two numbers to be added. Contrast DYADIC OPERATION.

monetize the process of converting a web page or other digital content so that it earns revenue. For example, see the Amazon Associates program affiliate-program.amazon.com/gp/associates/join.

monitor

1.a computer program that supervises the activity of other programs.

2.a device similar to a television set that accepts video signals from a computer and displays information on its screen. The monitor itself does no computing at all. See also COMPUTER; CRT; EYEGLASSES; LCD; SVGA; VGA.