M A| B| C| D| E| F| G| H| I| J| K| L| M| N| O| P| Q| R| S| T| U| V| W| X| Y| Z| Numerical Listing| MAC (Medium Access Control) The methods used to gain access to the physical layer of a local-area network. MAC (Message Authentication Code) A way of confirming that a message has not been tampered with. Magneto-Optic Information stored by local magnetization of a magnetic medium, using a focused light beam to produce local heating and consequent reduction of coercivity so that a moderately strong, poorly localized magnetic field can flip the state of a small region of high coercivity material. Reading is done either magnetically, with inductive heads in close proximity to the medium, or optically, through rotation of the plan of polarization of probing light via the Faraday effect or Kerr effect. MAN (Metropolitan-Area Network) MAN is a technology that evolved from local-area network designs, but is optimized for longer distances (over 50 kilometers), greater speeds (more than 100 megabits per second) and diverse forms of information (e.g., voice, data, image and video). Mandatory Security Controls An operating system security rating of B1 or higher based on U.S. Department of Defense trusted computer system evaluation criteria. TOP OF PAGE Manufacturing Lead Time The total time required to manufacture an item. Included here are order preparation time, queue time, setup time, run time, move time, inspection and put-away time. Manufacturing Operations Management (MOM) An integrated architecture that links applications residing within the seven agents of manufacturing. These agents are operations, job, material, equipment, labor, regulatory, and quality management. Manufacturing Resource Planning (MRP II) A method for effective planning of all the resources of a manufacturing company. Ideally, it addresses operational planning in units, financial planning in dollars, and has a simulation capability to answer "what if" questions. It is made up of a variety of functions, each linked together: Business Planning, Production Planning, Master Production Scheduling, Material Requirements Planning, Capacity Requirements Planning and the execution systems for capacity and priority. Outputs from these systems will be integrated with financial reports, e.g., the business plan, purchase commitment report, shipping budget, and inventory projections in dollars. MRP II is a direct outgrowth and extension of material requirements planning. MRP II is now migrating toward Enterprise Resource Planning (ERP). MAPI (Messaging Applications Programming Interface) Programming interface specification that enables an application to send and receive mail over a Microsoft Mail messaging system. It was designed to separate the mail engine from the mail client. MAPICS (Manufacturing Accounting and Production Information Control System) IBM’s material requirements planning software for the AS/400 and earlier System/36 and System/38 systems. The newest version, MAPICS/DB, uses the relational database capabilities of the AS/400. Materials Management A term to describe the grouping of management functions related to the complete cycle of material flow, from the purchase and internal control of production materials to the planning and control of work-in-process to the warehousing, shipping and distribution of the finished product. It differs from materials control in that the latter term, traditionally, is limited to the internal control of production materials. MB or Mbyte (Megabyte) The common abbreviation for megabyte; a megabyte is one million bytes. TOP OF PAGE Mbps (Megabits Per Second) A measure of data transmission rate, meaning one million bits per second. MC (Memory Channel) An additional level in the memory hierarchy of certain Encore computers, with an address space shared across clustered nodes. A write from local memory to the MC in one node simultaneously writes to reflective memories in all the other nodes. Each node can be attached to four separate MCs, allowing bandwidth scaling and substantial configuration flexibility. The MC also is used as a fast, low-latency transport for I/O transfer, for remote procedure calls and for general message passing. Message Passing Operating System An operating system that enables a process anywhere in a network to communicate via messages with any other process in the network. MFLOPS (Millions of Floating-Point Operations Per Second) A measurement for performance on compute-intensive, floating-point-intensive applications. The most commonly cited benchmark is Linpack. MHS (Message Handling Service) Utility in Novell NetWare platform providing a common format for exchanging information among applications. Used typically for electronic mail. MHz (Megahertz) A unit equal to 1 million hertz (1 million cycles per second). MIB (Management Information Base) A simple network management protocol flat-file, nonrelational database that describes devices being monitored. TOP OF PAGE MICR (Magnetic Ink Character Recognition) Machine recognition and digitization of magnetically charged characters printed on paper (typically bank drafts and deposit slips). Micro Channel Architecture This architecture was introduced on the IBM PS/2, supporting peripheral operations on the bus. It is IBM-proprietary, and may be the most important PS/2 innovation, because IBM is expected to unveil significant Micro Channel functionality over the next few years. Microcode The microinstructions, especially of a microprocessor, that govern the details of operation. For example, the hardware of the 3081 fetches and executes 108-bit microinstructions wholly different from the instruction set of System/370. Yet IBM supplies a microprogram that causes the 3081 to act like a System/370. The instructions in such a program are referred to as microcode. The execution of each System/370 instruction puts the hardware into a subroutine of microinstructions that execute the function defined for that instruction. Microcoded functions can improve performance but add a layer of complexity. For example, microcode errors appear to software as being hardware failures. Microfilm A high-resolution film used to record images reduced in size from the original. Middleware Originally, middleware was defined broadly as the run-time system software layered between an application program and the operating system. In that sense, database management systems (DBMSs) and transaction processing (TP) monitors represent middleware, but development tools or system management utilities do not, because they do not directly support the application at run-time. Now, middleware is more commonly and narrowly defined as the network-aware system software, layered between an application, the operating system and the network transport layers, whose purpose is to facilitate some aspect of cooperative processing. Examples of cooperative middleware include directory services, message passing mechanisms, distributed TP monitors, object request brokers, remote procedure call (RPC) services and database gateways. Midrange System End-User Query An end-user query facility on the midrange system that allows direct access to System/370 VSAM (Virtual Storage Access Method) or DB2 data using remote access facilities. MIME (Multipurpose Internet Mail Extensions) The Internet Engineering Task Force specification that provides X.400-like multimedia extensions to the Simple Mail Transport Protocol that is layered on top of TCP/IP networks. TOP OF PAGE MIPS (Million Instructions Per Second) An approximate figure to denote a computer’s raw processing power. It is often misleading, since it does not necessarily provide a creditable throughput figure of merit. MIPS RISC A reduced instruction set computer processor architecture designed and licensed by MIPS Computer Systems Inc. It is used by a number of midrange suppliers and is the basis for the Advanced Computing Environment-endorsed ARC (Advanced RISC computing) definitions. MIS (Management Information Systems) The name for the central data processing organization in a commercial enterprise. MMI (Man-Machine Interface) End-user interface. MMS (Manufacturing Message Service) Part of layer seven in the Open System Interconnection seven-layer network protocol stack. MMS creates a common communications interface between application software and factory devices such as programmable logic controllers, numerical controllers and robots. MO:DCA (Mixed Object: Document Content Architecture) The definition of the interchange data stream for documents containing a mixture of information types, such as text, image and graphics. Modem A conversion device installed in pairs, at each end of an analog communications line. The word is a contraction of modulate and demodulate. The transmitting-end modem modulates digital signals received locally from a computer or terminal (sending analog signals over the line). The receiving-end modem demodulates the incoming signal, converting it back to its original (i.e., digital) format and passes it to the destination business machine. Modulation The application of information onto a carrier signal by varying one or more of the signal’s basic characteristics (frequency, amplitude or phase); the conversion of a signal from its original (e.g., digital) format to analog format. MOM (Manufacturing Operations Management) An integrated architecture that links applications residing within the seven agents of manufacturing. These agents are operations, job, material, equipment, labor, regulatory, and quality management. Monitor Computer hardware used for displaying digital output. Mosaic A user-friendly Internet front end developed at the University of Illinois. TOP OF PAGE Motif Graphical user interface specified by the Open Software Foundation and built on the Massachusetts Institute of Technology’s X Windows. MPC (Multimedia PC) Specifications for a multimedia PC from the Multimedia PC Marketing Council, first published in 1990. Requires adherence to minimum RAM, processor, CD-ROM transfer rates, sound sampling, video, and port standards. MPE (Multiprogramming Executive) A multitasking operating system that is used on the Hewlett Packard 3000 series. MPEG (Motion Pictures Experts Group) An emerging standard for compression of full-motion images driven by the same committee as the Joint Photographic Experts Group standard. MPP (Massively Parallel Processors) Multiple processors tied together in configurations of 100 or more processors, with some type of message passing and processing capability. MPP (Massively Parallel Processing) An architecture that uses hundreds or thousands of parallel processors. MPTN (Multiprotocol Transport Networking) A multiprotocol network support including transaction control protocol over systems network architecture and systems network architecture over internet protocol, designed by IBM. TOP OF PAGE MRP (Material Requirements Planning) Original manufacturing business software that focused only on planning the manufacturing materials and inventories and did not integrate planning for other resources, like people and machine capacity. MRP II (Manufacturing Resource Planning) A method for effective planning of all the resources of a manufacturing company. Ideally, it addresses operational planning in units, financial planning in dollars, and has a simulation capability to answer "what if" questions. It is made up of a variety of functions, each linked together: business planning, production planning, master production scheduling, material requirements planning, capacity requirements planning and the execution systems for capacity and priority. Outputs from these systems will be integrated with financial reports, e.g., the business plan, purchase commitment report, shipping budget, and inventory projections in dollars. MRP II is a direct outgrowth and extension of material requirements planning. MRP II is now migrating toward enterprise resource planning. MS-DOS An operating system written by Microsoft for personal computers, and the basis for IBM’s PC-DOS. There are only trivial differences between the two operating systems. MS-DOS is used by all IBM PC-compatible machines. MSS (Mobile Satellite Service) Mobile earth stations (e.g., on board ships, survival stations, and positioning radio beacons) that provide location identification using satellite service. MTA (Message Transfer Agent) The storing and forwarding part of an electronic mail system. MTBF (Mean Time Between Failure) The cumulative average time that a manufacturer estimates between failures or occurrences in a component, complete telephone system or printed circuit board. TOP OF PAGE MTTR (Mean Time To Repair) An estimated average time, by either vendor or manufacturer, required to do repairs on equipment. Multimedia Applications and technologies that manipulate text, data, images and voice full motion video objects. Typically associated with PCs, but increasingly associated with networked-based applications. Multiplexer (Mux) A device that combines inputs from two or more terminals, computer ports, or other multiplexers, and transmits the combined datastream over a single high-speed channel. At the receiving end, the high-speed channel is demultiplexed, either by another multiplexer or by software. Multiprocessor A computer that incorporates multiple processors with access to a common storage. Multivendor Network Management Support for integration of network management on a common workstation. The network management facility should enable user organizations or third-party vendors to integrate additional network management tools. MVS (Multiple Virtual Storage) IBM’s flagship operating system. Essentially all the device support, software functions, time-sharing aids and reliability improvements that IBM produces are positioned most firmly within multiple virtual storage. Many VM microcode assists were designed so that MVS guests can run more effectively in that environment. Of all of IBM’s software products, MVS has by far received the greatest investment for development, documentation and support. Unless qualified, MVS refers either to all versions of MVS currently in the field (and these are legion) or to the latest version (the context may be a guide). MVS/370 The version of MVS denoted MVS/SP1. It is limited to 24-bit addressing and lacks the dynamic channel subsystem. Dropped from support in the early 1990s. TOP OF PAGE MVS/ESA (Multiple Virtual Storage/Enterprise System Architecture) A version of MVS introduced by IBM in February 1988. Capable of addressing up to 16 terabytes of data. Runs on the 3090 E and S models, as well as on the 4381 E. Consists of MVS/SP1.3 plus the latest DFP data management system. Comments? Questions? Entire contents Copyright © 1997, 1998 by Gartner Group, Inc. All rights reserved. Reproduction of this publication in any form without prior written permission is forbidden. Please read the guidelines for customer use of GartnerGroup intellecual property.