Barrons Publishing Dictionary of Computer and Internet Terms 10th

M

Mac nickname for MACINTOSH.

MAC address (Media Access Control address) a built-in number that uniquely and permanently identifies a network adapter, such as the Ethernet card in a PC. It consists of 12 hexadecimal digits, which may be written with or without hyphens, such as 13-24-6C-2D-FF-3A or 13246C2DFF3A.

Under Windows 2000 and later, the MAC address can be displayed by typing ipconfig /all at a COMMAND PROMPT.

Contrast IP ADDRESS, which is assigned manually or automatically by network administrators. See also GUID.

Mac OS the operating system for Macintosh computers; the latest version is version X (ten). It is based, in part, on the UNIX operating system. As a matter of fact, OS X runs BSD UNIX in its command line window. The foundation of Mac OS X is very reliable and solid; its user interface is still uncluttered, consistent, and easy to use. The elegantly simple idea of choosing an object and then telling the computer what to do with it has been carried through all versions of the Mac operating system, desktop accessories, and third-party applications. The idea was even adopted by the PC world (see WINDOWS). Today, a person familiar with one operating environment can pretty much sit down at any computer and, within minutes, be doing productive work.

The minor updates to OS X have been given the names of members of the big cat family:

Jaguar v10.2

Panther v10.3

Tiger v10.4

Leopard v10.5

Mac OS X Snow Leopard, the next upgrade, is scheduled to ship in 2009.

See APPLE MENU; CLASSIC MODE; DOCK; FINDER.

machine-dependent program a program that works on only one particular type of computer.

machine-independent program a program that can be used on many different types of computers. The usual way to make a program machineindependent is to write it in a widely used programming language, such as C or C++, and compile it separately for each machine. A Java program is machine-independent because it is compiled to a standard bytecode, which can be run using the Java virtual machine (JVM) available for each specific machine.

machine language instructions that a computer can execute directly. Machine language statements are written in a binary code, and each statement corresponds to one machine action.

The difference between machine language and assembly language is that each assembly-language statement corresponds to one machine-lan- guage statement, but the statements themselves are written in a symbolic code that is easier for people to read. (See ASSEMBLY LANGUAGE.) A single statement in a high-level language such as C may contain many machine instructions.

Macintosh a family of personal computers introduced by Apple in 1984; the first widely used computers with a graphical user interface, windowing, and a mouse. The Macintosh user interface was derived from that of Xerox workstations; it has been imitated by a number of other operating systems, including Microsoft Windows and OS/2 Presentation Manager.

The mechanisms for using windows, icons, and mouse menus are provided by the operating system, which means they look virtually the same in all programs. Thus, anyone who knows how to use any Macintosh software package will also know how to perform similar operations in any other software package. Macintosh hardware is simple to set up because of Apple’s early commitment to widely recognized standards such as PostScript, PDF, and SCSI.

There have been three generations of Macintosh hardware. The original Macintosh used the Motorola 68000 family of microprocessors. In 1994, Apple changed to the PowerPC microprocessor, and in 2006, to the Intel Pentium.

Macintoshes have always been on the forefront of practical computer graphics and related technology (for example, TrueType scalable fonts and QuickTime video), thus making them the preferred platform for the commercial arts.

The Macintosh uses BSD UNIX as its command-line mode and can run UNIX software without modification. This makes the Macintosh popular with scientists and programmers, which complements Apple’s original markets of graphic designers and office workers.

Although the selection of available software is smaller than with PCs, Apple maintains a loyal and vocal following for the Macintosh. The computers perform well and the Mac user community is close-knit. This may be one reason Macintosh computers are not as plagued with viruses as the Windows community.

Apple currently offers a variety of Macintosh computers, giving their customers a wide variety of solutions for their computing needs. There are two basic lines of laptops: iBooks and Powerbooks (student versus professional models, respectively). As for desktop-style computers, Apple offers a traditional high-end line of computers called Power Macs, but also offers the iMac, eMac, and Mac mini. The iMac is a very elegantly designed multi-use computer. eMacs were designed as a lowercost option to the iMac, but are adequate for most computing tasks. The

Mac mini is very small and easily transported. It can quickly hook up to any available monitor, mouse, and keyboard. The Mac mini is ideal for PC-users who also need access to a Macintosh computer.

The current version of the Macintosh operating system is MAC OS X

(read “ten,” not “x”). See also MICROPROCESSOR; POSTSCRIPT; POWERPC;

QUICKTIME; SCSI; TRUETYPE FONT.

macosx [sic] incorrectly spaced and capitalized abbreviation for Mac OS X, the tenth version of the Apple Macintosh’s operating system. See

MAC OS.

macro a user-defined sequence of instructions for a computer.

In assembly language and in programming languages such as C, macros are user-defined abbreviations for sequences of program statements. When the program is compiled, each occurrence of the macro is replaced by the instructions for which it stands. This contrasts with a FUNCTION, PROCEDURE, or METHOD, which is stored in one place in memory and called by the main program every time it is needed.

In application programs, macros are user-defined sequences of operations, which can be assigned to specific keys, placed on menus, or combined with pre-existing operations such as Open and Close. In Microsoft Office applications, you can use the Macro Recorder to save a sequence of keystrokes or mouseclicks as a macro, or you can program a macro in

VISUAL BASIC.

macro assembler any program that translates assembly language programs into machine code (see ASSEMBLY LANGUAGE) and allows the programmer to define macro instructions (see MACRO).

macro virus a virus written using the macro language of a particular application. For example, if a Microsoft Word document contains a macro virus that is designed to execute when the file is opened, an unsuspecting user who downloads the file and then opens it with Word will suffer the consequences of whatever the virus is programmed to do. Macro viruses are particularly dangerous because they can hide in word processing documents. Formerly, viruses could only be placed in executable code. Contrast TROJAN HORSE; VIRUS.

Macromedia producer of software to enhance the audiovisual content of web pages, including Dreamweaver, Flash, and Freehand. Macromedia was acquired by Adobe in 2005.

MAE (Metropolitan Area Exchange) a major connecting point where Internet service providers connect to the Internet. There are several MAEs in the U.S., divided into regions (MAE East, MAE Central, and MAE West). Web address: www.mae.net.

magenta a purplish-red color that is one of the standard printing ink colors.

See CMYK.

Majordomo a free, open-source software package for operating e-mail mailing lists and discussion groups, distributed from www.greatcircle.com. Majordomo is written in Perl and runs primarily on UNIX systems. (The major-domo is the head servant in an aristocratic household.) Compare

LISTSERV.

make a command, in UNIX and similar operating systems, that manages the steps of creating a machine-language program or some other complex product of computation.

Typically, a large machine-language program is made by compiling several different source files, producing a group of object files, and then linking the object files together. (See SOURCE CODE; OBJECT CODE.) The make command manages this process. It looks at a makefile (Figure 163) that tells it how to create each of the files needed to generate the complete program. Then it looks at the date on which each file was last modified. If any file is newer than the other files made from it, make will do whatever is needed to update those files (typically compiling or linking). By using make, the programmer avoids recompiling anything that has not been changed.

The make command can actually manage any process in which files are made from other files. All it needs is a makefile containing the appropriate commands.

#Each entry consists of:

#A file

#A list of other files that file depends on

#A command to generate it from them

#Each indented line must actually begin with

#the Tab character (ASCII 9), not spaces.

makefile a file that controls the operation of the MAKE command. Under UNIX, by default, it is named makefile or Makefile and resides in the current directory.

malware malicious software. For examples see ADWARE; SPYWARE; VIRUS.

man pages (manual pages) the online documentation built into UNIX and accessed by the command

man command

where command is the command or system function you want to know about. A selling point of UNIX since the earliest days has been that its manuals are online. See UNIX.

management information systems (MIS) a field of study that deals with effective systems for the development and use of information in an organization. The complete information system includes not just the computers but also the people. Any effective information system must determine:

1.what the goals of the organization are;

2.what information is needed to accomplish those goals;

3.how that information is originated;

4.how the information needs to be stored and transferred to accomplish those goals.

Mandelbrot set a famous fractal (i.e., a shape containing an infinite amount of fine detail). It was discovered by Benoit Mandelbrot. The Mandelbrot set is the set of values of c for which the series zn+1 =(zn)2 + c converges, where z and c are complex numbers and z is initially (0, 0).

See COMPLEX NUMBER.

The detail in the Mandelbrot set fascinates mathematicians. In Figure 164, the x and y axes are the real and imaginary parts of c. The Mandelbrot set is the black bulbous object in the middle; elsewhere, the stripes indicate the number of iterations needed to make |z| exceed 2.

FIGURE 164. Mandelbrot set

manifest a list of the contents of a shipment; a list of files transmitted as a group.

Map Network Drive the operation, in Windows, that makes a directory on another computer act as if it were a local disk drive. To map a network drive, right-click on the Computer icon and select the Map Network Drive menu item. You will need to specify the server name, directory to map, and the drive letter to use. See also UNC.

FIGURE 166. Mask

master

1.the controlling unit in a pair of linked machines. Contrast SLAVE (definition 1).

2.one of a pair of IDE hard disks or other devices connected to the same IDE cable. Generally, jumpers have to be set on IDE devices to identify them as master and slave. Contrast SLAVE (definition 2).

master browser see BROWSE MASTER.

master page a design template that defines the overall appearance of every page of a printed document. See also GRID SYSTEM.

MathML (Mathematics Markup Language) an extension of HTML designed to facilitate the display of mathematical expressions. (See the W3C web site at www.w3.org.)

matrix see ARRAY.

maximize to make a window take over the whole screen or become as large as possible. To do this, click the mouse on the maximize button (see picture at WINDOW). See also MINIMIZE; RESTORE. Maximize is also an option under the CONTROL MENU.

On a Macintosh, use the ZOOM box (at the far right side of the window’s title bar) to enlarge a window.

MB abbreviation for MEGABYTE.

MBps megabytes per second. See also BAUD; MEGABYTE.

Mbps megabits per second. See BIT.

MCSE (Microsoft Certified Software Engineer) a credential for computer professionals who pass a series of proficiency exams from Microsoft.

MDI (multiple document interface) the ability to edit more than one file or drawing with a single copy of a Windows program.

meatware (slang, humorous) computer users (the parts of a computer system that are made of meat). Compare PEBKAC.

mebi- proposed metric prefix meaning ×1,048,576 (220), the binary counterpart of mega-. See METRIC PREFIXES.

mebibyte 1,048,576 bytes.

media plural of MEDIUM.

Media Center Edition see

media error a defect in the surface of a disk or tape, sometimes curable by formatting the disk or tape again.

media, invalid see INVALID MEDIA.

medium (plural media)

1.material used for storage of information. Magnetic disks, tapes, and optical disks are examples of storage media.

2.a way of presenting information to the computer user. Vision is one medium; sound is another. Multimedia computing uses visible displays of several types together with sound.

3.a means of mass communication, such as television.

medium-scale integration the construction of integrated circuits that contain from 10 to 100 logic gates. See INTEGRATED CIRCUIT.

meg short for MEGABYTE.

mega- metric prefix meaning ×1,000,000 or, in rating computer memories and disks, ×1,048,576 (= 1024 × 1024). Mega- is derived from the Greek word for “big.” See MEGABYTE; METRIC PREFIXES.

megabyte (MB) an amount of computer memory equal to 220 = 1,048,576 bytes = 1,024 kilobytes. One megabyte can store more than one million characters. See MEMORY.

In measuring disk capacity, megabyte sometimes means the same as when measuring memory. Sometimes, however, megabyte is used to mean 1 million bytes, or even 1,024,000 bytes (1024 × 1000). These different systems of measurement result in different numbers being used to describe the capacity of the same disk. See also GIGABYTE.

megahertz (MHz) million hertz or million cycles per second, a measure of the clock speed of a computer or the frequency of a radio signal. See

CLOCK; MICROPROCESSOR.

megapixel one million PIXELs, a measure of the size of a graphical image. For example, a 1024 × 1024-pixel image is often referred to as a megapixel. Table 9 shows how many megapixels are needed for various levels of image quality. See also DIGITAL CAMERA; EFFECTIVE MEGAPIXELS;

GROSS MEGAPIXELS; PAINT PROGRAM.

meme an idea or belief that spreads quickly from person to person, like an infection, whether or not it is true.

The term meme was introduced by evolutionary biologist Richard Dawkins in 1976 to denote important ideas, skills, or habits that are passed along from person to person almost like genes. On the Internet, however, the term is usually applied to sweeping fads.