MAC

See Media Access Control.

MAC Address

These addresses are hexadecimal in nature and are unique for each card. Each MAC address is assigned by the manufacturer. It is sometimes referred to as the network adapter card’s hardware address.

Macintosh

A brand of computer manufactured by Apple. Macintosh is the only successful line of computers neither based upon the original IBM PC nor running the UNIX operating system. Windows NT Server supports Apple computers despite their use of proprietary network protocols.

MacIP

In AppleTalk, the Network layer protocol encapsulating IP packets in Datagram Delivery Protocol (DDP) packets. MacIP also supplies substitute ARP services.

Machine Certificates

Digital certificates issued to machines instead of people.

MacOS

The operating system that runs on an Apple Macintosh computer. See also Macintosh.

Macro

A macro is a series of instructions designed to simplify repetitive tasks within a program such as Microsoft Word, Excel, or Access. Macros execute when a user opens the associated file. Microsoft’s latest macro programming language is simple to use, powerful, and not limited to Word documents. Macros are in mini-programs and can be infected by viruses. See also Macro Virus.

Macro Virus

A macro virus is a malicious macro. Macro viruses are written in a macro programming language and attached to a document file (such as Word or Excel). When a document or template containing the macro virus is opened in the target application, the virus runs, does its damage and copies itself into other documents. Continual use of the program results in the spread of the virus.

MAC Sublayer

See Media Access Control Sublayer.

MADCAP

See Multicast Address Dynamic Client Allocation Protocol.

Magneto-Optical Storage (MO)

A high-capacity network storage device capable of storing 5.2GB on a 5.25″ removable cartridge. The data on the cartridge is highly stable, and so MO storage is suitable for use as backup and archival storage. MO offers access speeds of 35ms, compared with CD-RW and DVD-R, which offer speeds of between 100 and 200 ms. See also CD ReWritable and Digital Video Disc-Recordable.

Magnifier

A Windows utility used to create a separate window to magnify a portion of the screen. This option is designed for users who have poor vision.

Mail-Based Replication (MBR)

A mechanism to replicate directory information through a messaging transport. This term applies to Exchange inter-site directory replication, and additionally, Active Directory replication through SMTP.

Mailbox

The generic term referring to a container that holds messages, such as incoming and outgoing messages.

Mail Exchanger (MX)

The designation of an SMTP mail server in a DNS database.

Mailing List

On the Internet, a group of people who share a common interest and who automatically receive all the e-mail posted to the listserver or mailing-list manager program. Contributions are sent as e-mail to the listserver and then distributed to all subscribers. Mailing lists are private or by invitation only; Usenet newsgroups, by contrast, are open to everyone. See also LISTSERV, Listserver, Newsgroup, and Usenet.

Mail Server Security Wizard

A take-you-by-the-hand configuration tool for setting up the needed rules and filters for allowing secure access to your mail server behind an ISA Server.

Mailslots

A connectionless messaging IPC mechanism that Windows NT uses for browse requests and logon authentication. See also Interprocess Communications.

Main Data Facility (MDF)

The primary network closet or room. The MDF usually contains switches, routers, hubs, uninterruptible power supplies (UPS), servers, printers, cabling, and other networking gear. The MDF often will have cabling that connects outlying closets (such as in a wing of a building) to itself so that outlying users have a way of connecting to the data facility.

Mainframes

A generic term for large powerful computers not based upon single-chip microprocessor technology. Mainframes usually used terminals with no computing ability for user interfaces and shared a central CPU throughout an organization. The central processing paradigm of the mainframe/terminal architecture is the antithesis of the distributed processing architecture implemented by local area networks and the client/server paradigm. Distributed processing has won the market, and mainframes are now being used as superservers. See also Client/Server and Server.

MAKEBT32.EXE

The command used to create Windows 2000 Professional Setup Boot Disks.

MAKEPIPE

A command-line utility that can be used in conjunction with the READPIPE utility to verify that the Named Pipes protocol is working properly.

Malicious Code

A piece of code designed to damage a system or the data it contains, or to prevent the system from being used in its normal manner.

Malware

A generic term used to describe malicious software such as viruses, trojan horses, malicious active content, etc.

MAN

See Metropolitan Area Network.

Management Information Base (MIB)

MIB is a database of information that can be read by management software designed to work with SNMP. Some examples of this management software are IBM’s OpenView.

Management Information System

A computer-based information system that integrates data from all the departments that it serves, to provide company management with the information it needs to make timely decisions, track progress, and solve problems.

Manchester Encoding

In communications, a method used to encode data and timing signals in the same transmitted data stream. The signal state during the first half of the bit period indicates its data value (1 is high; 0 is low). A transition to the opposite state in the middle of the bit period acts as the timing signal. See also 4B/5B encoding.

Mandatory User Profile

A profile that is created by an administrator and saved with a special extension (.man) so that the user cannot modify the profile in any way. Mandatory user profiles can be assigned to a single user or a group of users. See also User Profile.

Man Pages

Short for manual pages. In Unix, the online documentation. Each man page treats a single topic; some are short, and others are quite long. They are all organized in a standard format using these headings: Name, Synopsis, Description, Files, See Also, Diagnostics, and Bugs. See also Permuted Index.

Manufacturing Automation Protocol (MAP)

A protocol that was originally developed by General Motors and was designed for use in a manufacturing environment. See also Technical and Office Protocol.

Map

To translate one value to another.

MAP

See Manufacturing Automation Protocol.

MAPI

See Messaging Application Programming Interface.

Mapped Drive

A shared network folder associated with a drive letter. Mapped drives appear to users as local connections on their computers and can be accessed through a drive letter using My Computer.

Marimba, Inc.

A company founded by four of the original Sun Microsystems Java team to develop products for the creation and deployment of network-managed applications across the Internet and across corporate intranets. For more information on Marimba, Inc., see www.marimba.com. See also Castanet.

Mass Storage Device

Any device capable of storing many megabytes of information permanently, but especially those capable of random access to any portion of the information, such as hard disk drives and CD-ROM drives. See also Small Computer Systems Interface, IDE, and Hard Disk Drive.

Master Boot Record (MBR)

A record used in the Windows 2000 boot sequence to point to the active partition, which is the partition that should be used to boot the operating system. This is normally the C: drive. Once the MBR locates the active partition, the boot sector is loaded into memory and executed. See also Boot Record.

Master Boot Sector

The first sector of a hard disk. This sector is located at sector 1, head 0, track 0. The sector contains the master boot record. See also Master Boot Record.

Master Boot Sector Virus

Master boot sector viruses infect the master boot sector of hard disks, though they spread through the boot record of floppy disks. The virus stays in memory, waiting for DOS to access a floppy disk. It then infects the boot record on each floppy disk DOS accesses. Also known as Master Boot Record Virus. See also Boot Record.

Master Browser

The computer on a network that maintains a list of computers and services available on the network and distributes the list to other browsers. The Master Browser may also promote potential browsers to be browsers. See Browser, Browsing, Potential Browser and Backup Browser.

Master Business Continuity Professional

Abbreviated MBCP. A certification from Disaster Recovery Institute International (DRII) that covers advanced information on business continuity planning, disaster recovery, and associated work experience and board certification. See also Associate Business Continuity Professional and Certified Business Continuity Professional.

Master Certified Novell Engineer (Master CNE)

A Novell certification program for CNEs who want to focus on the support of enterprise-wide networks. Previously known as Enterprise CNE. Many consider the Master CNE program the advanced degree of NetWare certification, because candidates must demonstrate proficiency in specialized networking technologies, as well as an indepth knowledge of the NetWare operating system. Specializations are available in the general categories of Management, Connectivity, Messaging, and Internet/Intranet Solutions and in the client categories of AS/400 Integration, Unix Integration, and Windows NT Integration. See also Certified Novell Engineer.

Master Certified Novell Instructor (MCNI)

An advanced Novell certification program for trainers who want to teach Novell courses. An MCNI must have at least two years of teaching experience and be certified as a Master CNE; in addition, an MCNI must also complete an Annual Update Requirement to keep their skills up to date. See also Certified Novell Instructor.

Master CNE

See Master Certified Novell Engineer.

Master Database

The system database that contains all the settings for the SQL Server engine, including configurations, user accounts, and links to user databases. This information is known collectively as the system catalog.

Master DNS Server

See DNS Server, Master.

Maximum Burst

Specified in bytes or cells, the largest burst of information exceeding the insured rate that will be permitted on an ATM permanent virtual connection for a short time and will not be dropped even if it goes over the specified maximum rate. See also Insured Burst and Maximum Rate.

Maximum Burst Size (MBS)

In an ATM signaling message, this metric, coded as a number of cells, is used to convey the burst tolerance.

Maximum Cell Delay Variation (MCDV)

The maximum two-point CDV objective across a link or node for the identified service category in an ATM network. The MCDV is one of four link metrics that are exchanged using PTSPs to verify the available resources of an ATM network. Only one MCDV value is assigned to each traffic class.

Maximum Cell Loss Ratio (MCLR)

The maximum ratio of cells in an ATM network that fail to transit a link or node compared with the total number of cells that arrive at the link or node. MCLR is one of four link metrics that are exchanged using PTSPs to verify the available resources of an ATM network. The MCLR applies to cells in VBR and CBR traffic classes whose CLP bit is set to zero. See also Constant Bit Rate, Cell Loss Priority, and Variable Bit Rate.

Maximum Cell Transfer Delay (MCTD)

In an ATM network, the total of the maximum cell delay variation and the fixed delay across the link or node. MCTD is one of four link metrics that are exchanged using PNNI topology state packets to verify the available resources of an ATM network. There is one MCTD value assigned to each traffic class. See also Maximum Cell Delay Variation.

Maximum Rate

The maximum permitted data throughput on a particular virtual circuit, equal to the total of insured and uninsured traffic from the traffic source. Should traffic congestion occur, uninsured information may be deleted from the path. Measured in bits or cells per second, the maximum rate represents the highest throughput of data the virtual circuit is ever able to deliver and cannot exceed the media rate. See also Excess Rate and Maximum Burst.

Maximum Transmission Unit (MTU)

The largest packet size, measured in bytes, that an interface can handle.

MB

See Megabyte.

MBONE

See Multicast Backbone.

MBR

See Master Boot Record.

MBS

See Maximum Burst Size.

MCA

Micro Channel Architecture; IBM’s standard for construction of PCs introduced in the 1990s.

MCDV

See Maximum Cell Delay Variation.

MCLR

See Maximum Cell Loss Ratio.

MCNI

See Master Certified Novell Instructor.

MCR

See Minimum Cell Rate.

MCTD

See Maximum Cell Transfer Delay.

MD

Creates a directory.

MDB

An instance of a database implemented in Exchange server. A single MDB is normally identified as being public or private depending on the type of data that it stores. A single Exchange 2000 server can accommodate up to 24 active MDBs.

Media Access Control (MAC)

The lower sublayer in the Data Link layer, it is responsible for hardware addressing, media access, and error detection of frames. See also Data Link Layer and Logical Link Control Sublayer.

Media Access Control (MAC) Address

Hardware address burned into the Network Interface cards. Six bytes long, three given to the manufacturer by the IEEE, and three bytes designated by the manufacturer.

Media Access Control (MAC) Sublayer

A sublayer in the Data Link layer of the Open Systems Interconnection (OSI) model. The MAC sublayer is used for physical addressing. See also Data Link Layer and Open Systems Interconnection Model.

Media Access Protocol

A specification for arbitrating access to physical network media among all devices that wish to transmit on the network. CSMA/CD is a media access protocol.

Megabyte (MB)

1,024 kilobytes of information or storage space.

Megahertz (MHz)

Speed of a processor in million of cycles per second.

MEM

Displays the amount of used and free memory in your system.

Member Server

An NT server that has been installed as a non-domain controller. This allows the server to operate as a file, print and application server without the overhead of accounts administration.

MEMMAKER

Starts the Memmaker program, which optimizes your computer’s memory.

Memory

Any device capable of storing information. This term is usually used to indicate volatile random access semiconductor memory (RAM) capable of high-speed acccess to any portion of the memory space, but incapable of storing information without power. See also Random Access Memory and Mass Storage Device.

Memory Management Unit (MMU)

The part of the processor that manages the mapping of virtual memory addresses to actual physical addresses. In some systems, such as those based on early Intel or Motorola processors, the MMU was a separate chip; however, in most of today’s systems, the MMU is integrated into the processor itself.

Memory-Resident Virus

A memory-resident virus stays in memory after it executes and infects other files when certain conditions are met. In contrast, non-memory resident viruses are active only while an infected application runs.

Menu

A list of available options as appears in the DOSSHELL.

Menu Bar

The horizontal bar that lists the names of menus.

Mesh Topology

A topology in which every device is connected to every other device on the network. When a new device is added, a connection to all existing devices must be made.

Message/Communication Services

A service that transfers messages and or communications to many different computers.

Message Switching

A type of network communication that sends an entire message, or block of data, rather than a simple packet.

Message Transfer Agent (MTA)

The component in all versions of Exchange Server that transfer messages between servers using the X.400 protocol.

Messaging Application Programming Interface (MAPI)

The API that is used by Microsoft messaging applications such as Outlook to access collaboration data. MAPI, or more specifically, MAPI Remote Procedure Calls (RPC), is also used as the transport protocol between Outlook clients and Exchange servers.

Messaging Bridgehead Server

An Exchange server designated to deliver messages to another site.

Metabase

A store that contains metadata such as that used by IIS to obtain its configuration data. The metabase can be viewed through utilities such as Metaedit.

Metabase Update Service

A component in Exchange 2000 that reads data from Active Directory and transposes it into the local IIS metabase. The metabase update service allows the administrator to make remote configuration changes to virtual servers without a permanent connection to each system.

Metadata

Data about data. In relation to Exchange, this term can be used in the context of Active Directory, but can also be used to describe the structure within the store or the MTA.

Metric

Cost information used to calculate the most efficient route for packets to take.

Metropolitan Area Network (MAN)

A network spanning a single city or metropolitan area. A MAN is larger than local area networks (LANs), which are normally restricted to a single building or neighboring buildings, but smaller than wide area networks (WANs), which can span the entire globe.

MIB

See Management Information Base.

Microcom Networking Protocol (MNP)

A set of communication protocols from Microcom, Inc., that has become the standard for data compression and error detection and correction. These days the CCITT V standards are implemented in modems due to their worldwide acceptance; however, some modem manufacturers offer both. For more information on Microcom, Inc., see www.microcom.com. See also Consultative Committee for International Telephony and Telegraphy.

Microprocessor

An integrated semiconductor circuit designed to automatically perform lists of logical and arithmetic operations. Modern microprocessors independently manage memory pools and support multiple instruction lists called threads. Microprocessors are also capable of responding to interrupt requests from peripherals and include onboard support for complex floating point arithmetic. Microprocessors must have instructions when they are first powered on. These instructions are contained in nonvolatile firmware called a BIOS. See also Basic Input/Output System and Operating System.

Microsoft Access

A popular relational database program from Microsoft.

Microsoft BackOffice

A network software suite from Microsoft that runs on Windows NT Server and consists of Microsoft Exchange Server, Microsoft SQL Server, Microsoft Site Server, Microsoft SNA Server, Microsoft Proxy Server, and Microsoft System Management Server. See also Microsoft Office.

Microsoft Certified Product Specialist

See Microsoft Certified Professional.

Microsoft Certified Professional (MCP)

A basic certification from Microsoft designed to establish expertise with at least one Microsoft operating system. Previously known as Microsoft Certified Product Specialist.

Microsoft Certified Solutions Developer (MCSD)

An advanced certification from Microsoft for computer professionals who develop custom applications using Microsoft products and computer programming language packages. Three core exams focus on operating system architecture, and two elective exams concentrate on programming and database concepts and skills.

Microsoft Certified Systems Engineer (MCSE)

An advanced certification from Microsoft that requires passing four core and two elective exams. The core exams cover the basic concepts and skills involved in installing, using, maintaining, and troubleshooting a Windows 2000 Server network, and the elective exams cover other server topics and advanced networking concepts. An MCSE+Internet certification is also available and covers the use of Internet Explorer, designing and building a Web site using Internet Information Server, and configuring and troubleshooting Microsoft’s implementation of TCP/IP.

Microsoft Certified Trainer (MCT)

A certification from Microsoft for technical trainers. An MCT certification is required before you can teach Microsoft Official Curriculum courses at Microsoft Authorized Technical Education Centers.

Microsoft CHAP (MS-CHAP)

A protocol that Microsoft created, compatible with CHAP, with capabilities of working with various members of the Windows family of operating systems.

Microsoft Commercial Internet Server (MCIS)

A Microsoft suite of commercial-grade server applications marketed to Internet Service Providers, telecommunication carriers, cable network operators, etc. Applications include MCIS Mail Server, Chat Server, and News Server, among others.

Microsoft Corporation

The world’s largest and most successful software company, founded in 1975 by Bill Gates and Paul Allen. Microsoft’s great initial success was in supplying IBM with the PC-DOS operating system for the IBM PC and then providing versions of MS-DOS to the clone manufacturers. Microsoft released Windows 3 in May 1990 and continued to upgrade Windows regularly. The release of Windows NT during 1993 consolidated Microsoft’s position as a leading developer of operating systems, and Windows 2000, Windows 2003, and Windows 2008 continue this trend. For more information on Microsoft, see www.microsoft.com.

Microsoft Disk Operating System (MS-DOS)

A 16-bit operating system designed for the 8086 chip that was used in the original IBM PC. Because IBM was unable to ship a better operating system, MS-DOS became the standard operating system used in microcomputers. MS-DOS is a simple program loader and file system that turns over complete control of the computer to the running program and provides very little service beyond file system support and that provided by the BIOS.

Microsoft Excel

A popular spreadsheet program from Microsoft.

Microsoft Exchange Server

A client/server message-management system from Microsoft. Exchange Server provides enterprise-wide message exchange by integrating e-mail, scheduling, document sharing, and electronic forms and also connects to the Internet and other networks outside the enterprise allowing global messaging. Exchange uses Microsoft Outlook as the client. Exchange Server is a component of Microsoft BackOffice. See also Microsoft BackOffice.

Microsoft FrontPage

An HTML editor from Microsoft that combines Web page creation with graphical Web site publication and management.

Microsoft Installer (MSI)

A standard that is used to automatically deploy applications with Windows Installer packages.

Microsoft Internet Explorer

A popular Web browser from Microsoft, which is also integrated into the Windows operating systems.

Microsoft Internet Information Server

A powerful and capable Web server package from Microsoft that runs on Windows Server. See also
Microsoft Site Server.

Microsoft LAN Manager

A network operating system, developed by Microsoft and 3Com, based on a version of OS/2; client PCs can run OS/2, MS-DOS, Unix, or Macintosh. Disk mirroring, disk duplexing, and UPS (uninterruptible power supply) monitoring functions are available. The network operating system supports IPX/SPX, TCP/IP, and NetBEUI. LAN Manager interoperates with, and has largely been superseded by, Windows NT Server.

Microsoft Management Console (MMC)

The Windows console framework for management applications. The MMC provides a common environment for snap-ins.

Microsoft NetMeeting

An Internet-based audio- and video-conferencing application from Microsoft.

Microsoft NetShow

A client/server streaming audio and video application from Microsoft. The NetShow server runs on Windows NT and streams audio, video, and animation to the client, a multimedia player.

Microsoft Office

A popular business software suite from Microsoft that runs on Microsoft Windows and the Macintosh and includes Microsoft Word, Microsoft Excel, Microsoft PowerPoint, Microsoft Outlook, Microsoft Access, Microsoft Publisher, and Microsoft InfoPath. See also Microsoft BackOffice.

Microsoft Office Expert (MOE)

An advanced certification from Microsoft that demonstrates complete familiarity with the Microsoft Office suite of applications, both individually and as a group.

Microsoft Office Expert Specialist (MOES)

A middle-level certification from Microsoft that demonstrates familiarity with more complex tasks in the Microsoft Office suite of applications.

Microsoft Office Proficient Specialist (MOPS)

A basic certification from Microsoft that demonstrates familiarity with the basic tasks in Microsoft Word or Microsoft Excel.

Microsoft Outlook

A popular e-mail application from Microsoft, which also includes scheduling and calendar functions, a contact-management module, and a simple project-management tool.

Microsoft Outlook Express

An easy-to-use e-mail application, distributed with Internet Explorer; both are available from Microsoft.

Microsoft Query

A utility used to graphically create SQL statements for any ODBC-compliant data source. Microsoft Query (also called MS Query) can link to Microsoft Office applications (such as Word and Excel), and other ODBC-compliant applications and databases.

Microsoft Services for Macintosh

Software that allows a Macintosh client to share files on a Windows server.

Microsoft Services for NetWare

Software for NetWare servers that allows NetWare clients to access Windows services.

Microsoft Site Server

A Microsoft package of tools for creating and managing Internet or intranet Web sites. Site Server includes Site Analyst, Usage Analyst, Personalization System, Commerce Server, Publishing Solution, Knowledge Management Solution, and the Analysis Solution. See also Microsoft Internet Information Server.

Microsoft SNA Server

A server component from Microsoft that provides Windows, Macintosh, MS-DOS, and OS/2 clients with access to IBM’s AS/400 and mainframe systems using System Network Architecture (SNA).

Microsoft SQL Server

A Windows Server-based relational database management system from Microsoft that also includes development tools, system management tools, data replication processes, and an open development environment.

Microsoft Systems Management Server

A set of network management tools from Microsoft, designed to provide a single point for managing network and client hardware and software (SMS hardware and software inventory functions track more than 200 properties for each desktop), software distribution, application metering and licensing, and troubleshooting.

Microsoft Terminal Server

A software package that provides clients with access to Windows-based applications running on the server rather than on the local system. The server receives and processes all keystrokes and mouse clicks sent from the client and sends the output back to the appropriate client. The server manages all resources for each connected client and provides each logged-in user with his or her own environment.

Microsoft Transaction Server

A package from Microsoft for developing and deploying distributed transaction-processing applications. See also Online Transaction Processing.

Microsoft Visual Basic (VB)

A version of the BASIC programming language that allows developers to create Windows applications quickly and easily.

Microsoft Windows

A general name for the family of operating systems available from Microsoft that includes Windows CE, Windows 95/98, Windows NT, Windows 2000, Windows XP, Windows Vista, and Windows 7.

Microsoft Windows 2000

A family of powerful operating systems from Microsoft, based on Windows NT, including Windows 2000 Professional for workstation users, Windows 2000 Server, and Windows 2000 Advanced Server. Windows 2000 Datacenter Server is a 64-bit version capable of addressing 64GB of physical RAM and managing 16 processors.

Microsoft Windows 3.1

A 16-bit graphical operating environment that runs on top of MS-DOS on Intel-based PCs, featuring overlapping windowed areas, drop-down menus, and mouse support. The three main elements of Windows 3.1 are the File Manager (used to manage files, directories, and disks), the Program Manager (which manages applications), and the Print Manager (which coordinates printers and printing).

Microsoft Windows 95

A 32-bit, multitasking, multithreaded desktop operating system capable of running MS-DOS, Windows 3.1, and Windows 95 applications. It supports Plug and Play (on the appropriate hardware) and adds an enhanced FAT file system in the Virtual FAT, which allows filenames of up to 255 characters while also supporting the MS-DOS 8.3 filenaming conventions. Windows 95 supports TCP/IP, IPX/SPX, NetBEUI, NDIS, FTP, SLIP, and PPP communications and networking protocols. See also Protocol.

Microsoft Windows 98

An evolutionary upgrade to Windows 95; includes an integrated Web browser, several other Web-based tools for conferencing, e-mail, Web page creation, and Web publishing. Windows 98 also includes a complete set of capable and easy-to-use tools for tasks such as defragmenting hard disks, compressing files, testing disks, and monitoring the system and supports new multimedia hardware and entertainment technologies. You can choose between the classic Windows interface familiar to Windows 95 users and the Active Desktop.

Microsoft Windows CE

A small, 32-bit operating system for hand-held portable computers and other specialized devices such as telephones, cable decoder boxes, and television sets.

Microsoft Windows NT Server

Microsoft 32-bit network operating system, which provides high levels of security, manageability, reliability, and performance. Runs on servers based on Intel, Alpha, and MIPS processors, includes preemptive multitasking and multiple threads of execution, and supports all major networking protocols. NT Server supports fault tolerance with disk mirroring, disk duplexing, RAID, and UPS monitoring. The user interface is similar to those available in other members of the Windows family. Windows NT Server includes Internet Information Server, DNS Server, and multiprotocol router support. All popular interprocess communications protocols for distributed computing are available, including Windows Sockets and Remote Procedure Calls (RPCs). See also Microsoft Windows 2000.

Microsoft Windows NT Services for Unix

A package from Microsoft Corporation that provides Unix services on a Windows NT system, including several popular command-line utilities, the Perl programming language, and a variety of Unix scripting tools.

Microsoft Windows NT Workstation

Microsoft 32-bit high-end operating system, which provides high levels of security, manageability, reliability, networking, and performance. Runs on workstations based on Intel, Alpha, and MIPS processors and supports preemptive multitasking and multiple threads of execution. The user interface is similar to those available in other members of the Windows family. See also Microsoft Windows 2000.

Microsoft Word

A popular and fully featured word processor from Microsoft. Wizards help users with tasks such as mail merge and formatting, and you can customized the various toolbars and menu bars to suit your individual needs. Word also supports a powerful macro language.

Micro-to-Mainframe

Any form of connection that attaches a PC to mainframe-based network. Often used to describe software (called terminal-emulation software) that allows the microcomputer to access data and applications on the mainframe system. See also Terminal Emulation.

Microwaves

A type of unbound network transmission medium. Microwaves are most often used to transmit data across satellite links and between earth-based equipment, such as telephone relay towers. Microwave transmission is commonly used to transmit signals when bounded media, such as cable, cannot be used. See also Broadband Network and Repeaters.

Middleware

Software that serves to connect client software to server software.

Midsplit

A special type of broadband cable system that divides the available frequencies into two groups: one for transmission and the other for reception. See also Broadband Network.

Migration

Moving resources, such as mailboxes, messages, etc. from one messaging system to another. See also Extraction, Importing, and Migration Wizard.

Migration Tool for NetWare

A utility used to migrate NetWare users, groups, file structures, and security to an NT domain. See also NetWare.

Migration Wizard

An Exchange program that extracts data from a foreign message system and imports it into Exchange.

Millisecond

Abbreviated ms or msec. A unit of measurement equal to one-thousandth of a second. In computing, hard disk and CD-ROM drive access times are often described in milliseconds; the higher the number, the slower the disk system.

Millivolt

Abbreviated mv. A unit of measurement equal to one-thousandth of a volt.

MILNET (MILitary NETwork)

Originally part of the ARPANET, MILNET was partitioned in 1984 to make it possible for military installations to have reliable network service, while the ARPANET continued to be used for research.

MIME

See Multipurpose Internet Mail Extension.

MIME Content Type

Information contained in a Multipurpose Internet Mail Extension (MIME) message header indicates the content type of the data contained in the next part of the message. See also Secure MIME.

Minicomputer

A medium-sized computer running a multitasking operating system capable of managing more than 100 users simultaneously, suitable for use in a small company or a single corporate or government department. See also Mainframes and Workstation.

Mini-Hard Disk

A hard disk mounted on a Type III PC Card. See also PC Memory Card International Association.

Minimum Cell Rate (MCR)

In Asynchronous Transfer Mode (ATM), the minimum cell rate that must be provided for a connection to conform to a specific quality of service (QoS) class. See also Asynchronous Transfer Mode, Available Cell Rate, Peak Cell Rate, and Sustainable Cell Rate.

MIP

See Multichannel Interface Processor.

MIPS

Acronym for millions of instructions per second. A measure of the processing speed of a computer’s CPU. See also Benchmark Program.

Mirrored

A mirrored filter rule creates two separate rules with opposite effects. For example, an inbound filter rule allowing traffic from any address to TCP port 80 will, when mirrored, create a rule allowing traffic to any address on TCP port 80.

Mirrored Volume

A volume set that consists of copies of two simple volumes stored on two separate physical partitions. A mirrored volume set contains a primary drive and a secondary drive. The data written to the primary drive is mirrored to the secondary drive. Mirrored volumes provide fault tolerance, because if one drive in the mirrored volume fails, the other drive still works without any interruption to service or loss of data.

Mirroring

The process of keeping a constant backup of server hard drive data on a second hard drive (or, in some cases, on another drive partition on the same drive). Every change made to the data on the primary hard drive is also immediately made on the second hard drive, so that if the first hard drive fails, the second can take over. This is similar to disk duplexing, but doesn’t require separate hard drive controllers.

Mirror Site

1. A duplicate Web site. A mirror site contains the same information as the original Web site and reduces traffic on that site by providing a local or regional alternative.
2. A duplicate data center. Large companies running mission-critical applications often mirror their entire data center so that the company can continue to function if the main center is hit by a natural disaster.

MIS

See Management Information System.

Mismatch

The situation when an Exchange server determines through the Knowledge Consistency Checker (KCC) that it does not have all the Exchange servers in the site in its Replication List.

Mission-Critical Application

A computer application whose function is vital to the operation of the corporation using it; also called line-of-business application.

Mixed Mode

In Microsoft Windows 2000 Server, a domain that contains at least one Windows NT domain controller. As a safety precaution, all Windows 2000 domains start up in mixed mode and must be converted to native mode manually. See also Native Mode.

Mixed-Mode Active Directory

An Active Directory mode that allows the use of Windows NT domain controllers.

Mixed Security

A SQL Server security mode that combines the functionality of integrated security with the flexibility of having SQL Server manage its own login accounts. In mixed mode, Windows NT accounts can be linked into SQL Server (using trusted connections), but unique SQL Server login accounts can also be created and used if a trusted connection is not possible. This is sometimes referred to as SQL Authentication in SQL Server.

Mixed-Vintage Site

Also known as PtOz. An Exchange 5.x site that also contains Exchange 2000 servers.

MJ

See Modular Jack.

MKDIR

Creates a directory.

MLID

See Multiple-Link Interface Driver.

MLP

See Multilink PPP.

MMC

See Microsoft Management Console.

MMJ

See Modified Modular Jack.

MMP

See Multichassis Multilink PPP.

MMU

See Memory Management Unit.

Mnemonic

Pronounced “nee-monic”. A name or abbreviation used to help you remember a long or complex instruction. Programming languages use many mnemonics to represent complex instructions.

MNP

See Microcom Networking Protocol.

MO

See Magneto-Optical Storage.

Mobile Computing

1. The daily use of a portable or laptop computer as a normal part of the workday.
2. Techniques used to establish links to a network by employees who move from one remote location to another, such as members of a sales staff or telecommuters who work from home. Once the connection is made, users log in and access network resources as easily as if they were working from a computer in the corporate office. See also Docking Station, Laptop Computer, Portable Computer, Port Replicator, and Wireless Communications.

Mobile IP

A mechanism that allows mobility on the Internet by allowing a computer to use the same IP address as it moves from one location to another. Mobile IP also allows a user to change from one medium, such as Ethernet, to another, perhaps a wireless connection. See also Ethernet and Internet Protocol.

MODE

Configures a system device.

Model Database

The template database for SQL Server that is used when new databases are created. All users, groups, and security existing in this database are automatically part of any new databases, but changes made to the Model database will not affect existing databases.

Modem

A device that converts a computer’s digital signal to an analog signal for transmission of information over a telephone line. See also Data Link Layer.

Modem Eliminator

A device that allows two computers to be linked without using modems. In an asynchronous system, in which the serial ports of two PCs are connected, the modem eliminator is a null-modem cable. In synchronous systems, a modem eliminator must also provide timing functions to synchronize communications.

Modem Server

A LAN server that allows a network user to dial out of the network into the Public Switched Telephone System or to access leased lines for synchronous communications. Also called an asynchronous communications server or a dial-in/dial-out server.

Moderated Newsgroup

On the Internet, a Usenet newsgroupor mailing list that is managed by one or more people in an attempt to maintain standards. All posts to the newsgroup are reviewed by the moderator to make sure they meet the standards the group has set for subject matter and commercial content before being passed on to the whole group. Moderation is not censorship but an attempt to avoid some of the more extreme antics of those who enjoy flame wars. See also Flame War, Listserver, Mailing List, and Moderator.

Moderator

A person or small group of people who review the contents of all posts to a Usenet newsgroup or Internet mailing list to ensure that the postings meet the standards set by the group. Moderators are almost always volunteers, so be nice to them. See also Moderated Newsgroup.

Modified Modular Jack (MMJ)

A six-pin connector developed by Digital Equipment Corporation used to connect serial lines to terminal devices. MMJ jacks have a side-locking tab and so can be distinguished from RJ-11 jacks, which have a center-mounted tab. See also Modular Jack and RJ-11.

Modular Jack (MJ)

The jack used to connect telephone cables to a wall-mounted face plate. See also Modified Modular Jack and RJ-11.

Modulation

The process of modifying some characteristic of an electrical signal, such as amplitude (AM) or frequency (FM), in order to represent digital or analog information. See also Amplitude Modulation.

Module

A software component of a modular operating system that provides a certain defined service. Modules can be installed or removed depending upon the service requirements of the software running on the computer. Modules allow operating systems and applications to be customized to fit the needs of the user.

Monitor

The display device connected to your PC.

MORE

Displays output one screen at a time.

MOSPF

See Multicast OSPF.

Mouse

A device used to manipulate a pointer around your display and activate a certain process by pressing a button.

MOVE

Moves one or more files. Also renames files and directories.

MP3 File

Moving Pictures Experts Group Audio Layer 3 File. MP3 files are highly compressed audio tracks, and are very popular on the Internet. MP3 files are not programs, and viruses cannot infect them. This file type has the extension MP3.

MPOA

See Multiprotocol Over ATM.

MPR

See MultiProtocol Router.

MSAV

Scans your computer for known viruses.

MSBACKUP

Backs up or restores one or more files from one disk to another.

MS-CHAP

See Microsoft CHAP.

MSD

Provides detailed technical information about your computer.

Msdb Database

A SQL Server database that stores information about the alerts, tasks, events, and replication tasks created on that server by the SQLServerAgent service. The Msdb database also includes information about system operators.

MS-DOS

See Microsoft Disk Operating System.

MSI

See Microsoft Installer.

MS Query

See Microsoft Query.

MTU

See Maximum Transmission Unit.

Multi-Booting

The process of allowing a computer to boot multiple operating systems. See also Boot.

Multicast

Broadly, any communication between a single sender and multiple receivers. Unlike broadcast messages, which are sent to all addresses on a network, multicast messages are sent to a defined subset of the network addresses; this subset has a group multicast address, which is specified in the packet’s destination address field. See also Broadcast and Directed Broadcast.

Multicast Address

A single address that points to more than one device on the network by specifying a special non-existent MAC address specified in that particular multicast protocol. Identical to group addresses. See also Multicast.

Multicast Address Dynamic Client Allocation Protocol (MADCAP)

A protocol that issues leases for multicast addresses only.

Multicast Backbone (MBONE)

The multicast backbone of the Internet, it is a virtual multicast network made up of multicast LANs, including point-to-point tunnels interconnecting them.

Multicast OSPF (MOSPF)

An extension of the OSPF unicast protocol that enables IP multicast routing within the domain. See also Open Shortest Path First.

Multicast Routing

This occurs when one machine sends to an entire network.

Multicast Send VCC

A two-directional point-to-point virtual control connection (VCC) arranged by an LEC to a BUS, it is one of the three types of informational link specified by phase 1 LANE. See also Control Distribute VCC and Control Direct VCC.

Multicast Scope

Range in which multicast addresses may be assigned.

Multichannel Interface Processor (MIP)

The resident interface processor on Cisco 7000 series routers, providing up to two channelized T1 or E1 connections by serial cables connected to a CSU. The two controllers are capable of providing 24 T1 or 30 E1 channel groups, with each group being introduced to the system as a serial interface that can be configured individually.

Multichassis Multilink PPP (MMP)

A protocol that supplies MLP support across multiple routers and access servers. MMP enables several routers and access servers to work as a single, large dial-up pool with one network address and ISDN access number. MMP successfully supports packet fragmenting and reassembly when the user connection is split between two physical access devices.

Multihomed Host

A computer connected to more than one physical data link. The data links may or may not be attached to the same network.

Multilayer Switch

A highly specialized, high-speed, hardware-based type of LAN router, the device filters and forwards packets based on their Layer 2 MAC addresses and Layer 3 network addresses. It is possible that even Layer 4 can be read. Sometimes called a Layer 3 switch. See also LAN Switch.

Multilink

A capability of RAS to combine multiple data streams into one network connection for the purpose of using more than one modem or ISDN channel in a single connection. See also Remote Access Service.

Multilink PPP (MLP)

A technique used to split, recombine, and sequence datagrams across numerous logical data links.

Multi-Master Environment

An environment in which multiple servers hold replicas of the same database (or portions thereof) and in which each of these servers can accept changes to the data and replicate those changes to the other servers.

Multimaster Replication Model

Used in Active Directory replication and in Active Directory-Integrated zone transfers. Enables multiple masters to update the zone. A master is any domain controller running Active Directory-Integrated DNS. Any of the domain controllers for the domain can modify the zone and replicate changes to the other domain controllers. This is better than standard DNS replication, in which only the primary server for a zone can modify the zone. See also Active Directory Replication, Full Zone Transfers, and Incremental Zone Transfers.

Multipartite Virus

Multipartite viruses use a combination of techniques including infecting documents, executables, and boot sectors to infect computers. Most multipartite viruses first become resident in memory and then infect the boot sector of the hard drive. Once in memory, multipartite viruses may infect the entire system. Removing multipartite viruses requires cleaning both the boot sectors and any infected files. Before you attempt the repair, you must have a clean, write-protected Rescue Disk.

Multiple-Link Interface Driver (MLID)

A Novell Open Datalink Interface (ODI) device driver that manages the sending and receiving of packets to and from the physical network medium. See also Link-Support Layer and Open Datalink Interface/Network Driver Interface Specification Support.

Multiple Station Access Unit (MSAU)

The hub in a Token Ring network.

Multiple Universal Naming Convention Provider (MUP)

A software component of Windows NT that allows two or more UNC providers, for example, for Microsoft networks and NetWare networks to exist simultaneously. The MUP determines which UNC provider will handle a particular UNC request and forwards the request to that provider. See also Universal Naming Convention and Multiprovider Router.

Multiplexer

A device that multiplexes signals for transmission over a segment and reverses this process for multiplexed signals coming in from the segment. Frequently shortened to mux.

Multiplexing

The process of converting several logical signals into a single physical signal for transmission across one physical channel.

Multipoint Control Unit (MCU)

A reference to the T.120 protocol that allows clients to connect to data conferencing sessions. MCUs can communicate with each other to transfer conferencing information.

Multiport Repeater

See Active Hub.

Multiprocessing

Using two or more processors simultaneously to perform a computing task. Depending upon the operating system, processing may be done asymmetrically, wherein certain processors are assigned certain threads independent of the load they create, or symmetrically, wherein threads are dynamically assigned to processors according to an equitable scheduling scheme. The term usually describes a multiprocessing capacity built into the computer at a hardware level in that the computer itself supports more than one processor. However, multiprocessing can also be applied to network computing applications achieved through interprocess communication mechanisms. Client/server applications are, in fact, examples of multiprocessing. See also Asymmetrical Multiprocessing, Symmetrical Multiprocessing, and Interprocess Communications.

Multi-Protocol

A network library available with SQL Server. Multi-Protocol allows SQL Server to communicate over any open interprocess communication (IPC) mechanism. It also provides support for integrated security and encryption. Multi-Protocol takes advantage of remote procedure calls (RPCs) to pass information between the client and server.

Multiprotocol Over ATM (MPOA)

An effort by the ATM Forum to standardize how existing and future Network-layer protocols such as IP, IPv6, AppleTalk, and IPX run over an ATM network with directly attached hosts, routers, and multilayer LAN switches.

MultiProtocol Router (MPR)

Services included with NT Server that allow you to route traffic between IPX and TCP/IP subnets. MPR also allows you to facilitate DHCP requests and forward BOOTP relay agents. See also Internetwork Packet Exchange, Transmission Control Protocol/Internet Protocol, Dynamic Host Configuration Protocol and Bootstrap Protocol.

Multiprotocol Routing

Allows a Windows computer to accept packets from other computers on its local network, sort out the correct destination for each, and route them accordingly.

Multiprovider Router

A software component of Windows NT that allows two or more Win32 network API providers to exist simultaneously. The MUP determines which Win32 network provider handles a particular API request and forwards the request to that provider. See also Multitasking.

Multipurpose Internet Mail Extensions (MIME)

An Internet protocol that enables the encoding of binary content within mail messages. For example, MIME could be used to encode a graphics file or word processing document as an attachment to a text-based mail message. The recipient of the message would also have to be using MIME to decode the attachment. MIME is newer than UUENCODE and in many systems has replaced it. See also UUENCODE.

Multitasking

The capacity of an operating system to rapidly switch among threads of execution. Multitasking allows processor time to be divided among threads as if each thread ran on its own slower processor. Multitasking operating systems allow two or more applications to run at the same time and can provide a greater degree of service to applications than single-tasking operating systems like MS-DOS. See also Multiprocessing.

Multithreaded

Multithreaded refers to programs that have more than one chain of execution, thus relying on the services of a multitasking or multiprocessing operating system to operate. Multiple chains of execution allow programs to simultaneously perform more than one task. In multitasking computers, multithreading is merely a convenience used to make programs run smoother and free the program from the burden of switching between tasks itself. On multiprocessing computers, multithreading allows the compute burden of the program to be spread across many processors. Programs that are not multithreaded cannot take advantage of multiple processors in a computer. See also Multitasking and Multiprocessing.

Municipal Area Network (MAN)

A network that spans a municipality.

MUP

See Multiple Universal Naming Connection Provider.

Mutant

See Variant.

Mutating Virus

A mutating virus changes, or mutates, as it progresses through its host files making disinfection more difficult. The term usually refers to viruses that intentionally mutate, though some experts also include non-intentionally mutating viruses. See also Polymorphic Virus.

Mutual Authentication

The type of authentication used with Kerberos. With mutual authentication, the user is authenticated to the service and the service is authenticated to the user.

Mux

See Multiplexer.

MX

See Mail Exchanger.

My Computer

The folder used to view and manage a computer. My Computer provides access to all local and network drives, as well as Control Panel. See also Control Panel.

My Documents

The default storage location for documents that are created. Each user has a unique My Documents folder.

My Network Places

The folder that provides access to shared resources, such as local network resources and Web resources.