N

N

n prefix See nano-.

NACN n. See North American Cellular Network.

nagware n. Slang for computer shareware that, on starting or before closing, displays a prominent reminder to pay for the program. See also shareware.

NAK n. Acronym for negative acknowledgement. A control code, ASCII character 21 (hexadecimal 15), transmitted to a sending station or computer by the receiving unit as a signal that transmitted information has arrived incorrectly. Compare ACK.

NAK attack n. Acronym for negative acknowledgement attack. A hacker attack that uses the negative acknowledgement control code character to enter a seemingly secure system. A NAK attack uses weaknesses in the system handling NAK replies that may leave it temporarily unprotected. See also NAK.

naked PC n. A personal computer sold without an operating system (OS) installed. The purchaser of a naked PC must then choose and install an OS before the computer can be used. Naked PCs are chiefly purchased by users with some degree of expertise with computer equipment who may want to install a version of Linux or an offshoot OS. Computer and software manufacturers have expressed concern over the possibility of software piracy with the sale of naked PCs.

.name n. One of seven new top-level domain names approved in 2000 by the Internet Corporation for Assigned Names and Numbers (ICANN), .name is meant for registration by individuals for personal Web sites. The seven new domain names became available for use in the spring of 2001.

Name Binding Protocol n. See NBP.

named anchor n. In HTML, a tag within a document that can act as a destination for a hyperlink. Named anchors are useful because they allow a link to a specific location within a document. Also called: named target. See also anchor (definition 2), HTML, hyperlink.

named entity n. See character entity.

named pipes n. In programming, one-way (simplex) or two-way (duplex) connections used to transfer data between processes. Named pipes are portions of memory set aside for temporary data storage. They are created by server processes and can be used simultaneously by more than one client process, each accessing a separate instance with its own buffers and handles. Named pipes can be used to transfer data either locally or on a network.

named target n. See named anchor.

name server n. See CSO name server, DNS server.

namespace n. 1. A grouping of one or more names that represent individual objects within the group in a shared computing environment, such as a network. The names within a namespace are unique, are created according to the same rules, and can be resolved into a particular identifying item of information, such as an IP address or a network device. A namespace can be either flat a single collection of unique names or hierarchical, as is the Internet s DNS (Domain Name System), which is based on a treelike structure that is refined through successive levels beginning with the root server and the Internet s top-level domains (.com, .net, .org, and so on). In everyday terms, a namespace is comparable to a telephone book, in which each name is unique and resolves to the phone number and address of a particular individual, business, or other entity. 2. A means of identifying elements and attributes in an XML document by assigning them a two-part name with the first part being the namespace and the second part being the functional name. A namespace identifies a set of names to prevent confusion when multiple objects with identical functional names are taken from different sources and brought together in the same XML document. Namespaces typically reference a Uniform Resource Identifier (URI) because each URI will be unique.

name-value pair n. 1. In the Perl programming language, a data set in which the data is associated with a name. See also Perl. 2. In CGI programming, one of the data items collected from an HTML form by the browser and passed through the server to a CGI script for processing. See also CGI, CGI script, HTML.

naming container n. Any ASP.NET control that implements the INamingContainer interface. This is a marker interface that enables a control to create a new naming scope under itself so that ID attributes assigned to its child controls are unique within the entire ASP.NET page that contains the control.

NAMPS n. Acronym for Narrow-band Analog Mobile Phone Service. A standard proposed by Motorola Corporation that combines the current AMPS cellular telephone standard with digital signaling information, resulting in higher performance and increased capabilities. See also AMPS.

NAND n. Short for NOT AND. A logical operation that combines the values of two bits (0,1) or two Boolean values (false, true) that returns a value of 1 (or true) if one input value is 0 (or false), and returns a 0 (false) only if both inputs are true.

NAND gate n. Short for NOT AND gate. A digital circuit whose output is true (1) if any input is false (0). A NAND gate is an AND circuit (output with the value of 1 when all input values are 1) followed by a NOT circuit (output that is the logical complement of the input). Thus, NAND gate output is high if any of its inputs are low. See also AND gate, gate (definition 1), NOT gate.

nano- prefix Abbreviated n. Metric prefix meaning 10 ⁹ (one billionth).

nanosecond n. One billionth of a second. A nanosecond is a time measure used to represent computing speed, particularly the speed at which electrical signals travel through circuits within the computer. Acronym: ns.

NAP n. See Network Access Point.

Napster n. An Internet music search application that allows users to search for and swap MP3 files over the Web. In response to a user request for a song or an artist, Napster searches the hard drives of all other Napster users on line. When the requested item is found, the file is downloaded to the computer making the request. Napster also includes a chat room and a library of most popular items. The introduction of Napster in 1999 sparked heated debate over copyright and digital distribution issues. See also MP3.

narrowband n. A bandwidth set aside by the FCC for mobile or portable radio services, such as advanced two-way paging systems, including transmission rates between 50 bps and 64 Kbps. Narrowband formerly referred to the bandwidth from 50 to 150 bps. See also bandwidth, FCC. Compare broadband.

narrowband ISDN n. Name used to distinguish current ISDN lines from the developing broadband ISDN technology. See also broadband ISDN, ISDN.

narrowcast vb. To transmit data or programming to a defined or limited area or audience. A cable television company narrowcasts its programs only to subscribers, whereas network television stations broadcast to everyone with reception equipment in their transmission range. On the Web, content delivered to users via push technology represents a form of narrowcasting. See also unicast. Compare broadcast (definition 2), multicasting.

Narrow SCSI n. A SCSI or SCSI-2 interface that can transfer data only 8 bits at a time. See also SCSI, SCSI-2. Compare Fast/Wide SCSI, Wide SCSI.

NAS n. Acronym for Network-Attached Storage. A platform-independent storage appliance connected to a network. NAS uses a storage unit with a built-in server that can communicate with clients over a network. NAS devices are popular for ease of maintenance, manageability, and scalability. Compare SAN.

NAT n. Acronym for Network Address Translation. The process of converting between IP addresses used within an intranet or other private network and Internet IP addresses. This approach makes it possible to use a large number of addresses within the private network without depleting the limited number of available numeric Internet IP addresses. Variations of NAT displaying similar functions include IP aliasing, IP masquerading, and Port Address Translation.

national attachment point n. See Network Access Point.

National Center for Supercomputing Applications n. See NCSA (definition 1).

National Committee for Information Technology Standards n. A committee formed by the Information Technology Industry Council to develop national standards for use in the information technology industry and to promote those standards for international use. Acronym: NCITS.

National Computer Security Association n. See ICSA.

National Information Infrastructure n. A U.S. government program to extend and oversee the development of the Information Superhighway. The National Information Infrastructure is made up of a high-bandwidth, wide area network that can carry data, fax, video, and voice transmissions to users throughout the United States. The network is being developed mostly by private carriers. Many of the services, which are aimed at enabling the efficient creation and dissemination of information, are already available on the Internet itself, including increased accessibility to quality education through distance learning and increased access to government services. Acronym: NII. See also Information Superhighway, Internet2, Next Generation Internet. Compare Internet.

National Institute of Standards and Technology n. A branch of the U.S. Commerce Department that works to develop and encourage standards for measurement, science, and technology in order to promote commerce and improve productivity in the marketplace. Prior to 1988, the National Institute of Standards and Technology was known as the National Bureau of Standards. Acronym: NIST.

national language support n. 1. The practice of creating programs that can display text in any language necessary. 2. A function in Windows that enables you to specify system and user locale information. Acronym: NLS.

National Science Foundation n. A U.S. government agency intended to promote scientific research by funding both research projects and projects that facilitate scientific communication, such as NSFnet, the former backbone of the Internet. Acronym: NSF. See also backbone (definition 1), NSFnet.

National Television System Committee n. See NTSC.

native adj. Of, pertaining to, or characteristic of something that is in its original form. For example, many applications are able to work with files in a number of formats; the format the application uses internally is its native file format. Files in other formats must be converted to the application s native format before they can be processed by the application.

native application n. A program that is designed specifically for a particular type of microprocessor, that is, a program that is binary compatible with a processor. A native application generally will run much faster than a nonnative application, which must be run with the help of an emulator program. See also binary compatibility, emulator.

native code n. Code that has been compiled to processor-specific machine code.

native compiler n. A compiler that produces machine code for the computer on which it is running, as opposed to a cross-compiler, which produces code for another type of computer. Most compilers are native compilers. See also compiler (definition 2), cross-compiler.

native file format n. The format an application uses internally to process data. The application must convert files in other formats to the native format before it can work with them. For example, a word processor might recognize text files in ASCII text format, but it will convert them to its own native format before it displays them.

native language n. See host language.

natural language n. A language spoken or written by humans, as opposed to a programming language or a machine language. Understanding natural language and approximating it in a computer environment is one goal of research in artificial intelligence.

natural-language processing n. A field of computer science and linguistics that studies computer systems that can recognize and react to human language, either spoken or written. See also artificial intelligence. Compare speech recognition.

natural language query n. A query to a database system that is composed in a subset of a natural language, such as English or Japanese. The query must conform to some restrictive syntax rules so that the system can parse it. See also parse, syntax.

natural-language recognition n. See speech recognition.

natural language support n. A voice recognition system that allows the user to use verbal commands in his or her own language to direct a computer s actions. Acronym: NLS.

natural number n. An integer, or whole number, that is equal to or greater than zero. See also integer.

navigation bar n. On a Web page, a grouping of hyperlinks for getting around in that particular Web site. See also hyperlink.

navigation keys n. The keys on a keyboard controlling cursor movement, including the four arrow keys and the Backspace, End, Home, Page Down, and Page Up keys. See also arrow key, Backspace key, End key, Home key, Page Down key, Page Up key.

Navigator n. See Netscape Navigator.

NBP n. Acronym for Name Binding Protocol. A protocol used on AppleTalk local area networks to translate between node names (known to users) and numeric AppleTalk addresses. NBP operates at the transport level (level 4 of the ISO/OSI reference model). See also AppleTalk, communications protocol, ISO/OSI reference model.

NC n. See network computer.

NCC n. See network-centric computing.

N-channel MOS n. See NMOS.

NCITS n. See National Committee for Information Technology Standards.

NCP n. See Point-to-Point Protocol.

NCR paper n. Short for no carbon required paper. A special paper used for multipart forms. NCR paper is impregnated with a chemical that darkens it when pressure is applied. See also multipart forms.

NCSA n. 1. Acronym for National Center for Supercomputing Applications. A research center located at the University of Illinois at Urbana-Champaign. NCSA was founded in 1985 as a part of the National Science Foundation, specializing in scientific visualization tasks, but is best known as the home of NCSA Mosaic, the first graphical Web browser, and of NCSA Telnet. See also Mosaic, NCSA Telnet. 2. See ICSA.

NCSA Mosaic n. See Mosaic.

NCSA server n. The HTTP server developed by the National Center for Supercomputing Applications of the University of Illinois. This server and the CERN server were the first HTTP servers developed for the World Wide Web and are available free through downloading. See also HTTP server (definition 1), NCSA (definition 1). Compare CERN server.

NCSA Telnet n. A freeware telnet client program developed and distributed by the National Center for Supercomputing Applications. See also client (definition 2), NCSA (definition 1).

NDIS n. Acronym for Network Driver Interface Specification, a software interface, or set of rules, designed to enable different network protocols to communicate with a variety of network adapters. Providing a standard a common language for the drivers used by network adapters, NDIS enables a single network adapter to support multiple protocols and, conversely, also enables a single protocol to work with network adapters from different vendors. See also device driver.

NDMP n. Acronym for Network Data Management Protocol. An open protocol for network-based backups of file servers that allows platform-independent data storage. See also backup, communications protocol, file server.

NDR n. See nondestructive readout.

NDRO n. See nondestructive readout.

NDS n. Acronym for Novell Directory Services. A feature introduced in Novell Netware 4.0 that provides access to directories that may be located on one or more servers.

near-letter-quality adj. A print mode on high-end dot-matrix printers that produces clearer, darker characters than normal (draft-quality) printing. Near-letter-quality printing, although it is sharper than plain dot-matrix printing, is not as legible as output from a fully-formed-character printer, such as a daisy-wheel printer. Acronym: NLQ. See also print quality. Compare draft quality, letter quality.

negation n. The conversion of a two-state (binary) signal or bit pattern to its opposite state for example, the conversion of 1001 to 0110.

negative acknowledgement n. See NAK.

negative entry n. The act of assigning a negative sign to a number that has been entered into a calculator, thereby transforming the number to a negative number.

nest vb. To embed one construct inside another. For example, a database may contain a nested table (a table within a table), a program may contain a nested procedure (a procedure declared within a procedure), and a data structure may include a nested record (a record containing a field that is itself a record).

nested transaction n. In programming, an operation or sequence of operations taking place within a larger transaction. A nested transaction can be aborted without requiring abortion of the larger transaction. Also called: subtransaction. See also nest.

.net n. In the Internet s Domain Name System, the top-level domain that identifies addresses of network providers. The designation .net appears at the end of the address. See also DNS (definition 1), domain (definition 3). Compare .com, .edu, .gov, .mil, .org.

net.- prefix A prefix used to describe people and institutions on the Internet. For example, a very well respected person might be described as a net.god.

Net n. 1. Short for Internet. 2. Short for Usenet.

.NET n. The set of Microsoft technologies that provides tools for connecting information, people, systems, and devices. The technologies provide individuals and organizations with the ability to build, host, deploy, and use XML Web service connected solutions.

net address n. 1. A World Wide Web address (URL). See also URL. 2. An e-mail address. 3. The DNS name or IP address of a machine. See also DNS (definition 1), IP address. 4. The address, burned into a network adapter, that is used to uniquely identify a node on a network. See also network interface card.

NetBEUI n. Short for NETBIOS Extended User Interface. NetBEUI is a network protocol created by IBM and now used by Microsoft, HP, and Compaq. It is usually used in small, department-size local area networks (LANs) of 1 to 200 clients. It can use Token Ring source routing as its only method of routing. It is the extended version of the NetBIOS standard. See also CCP, communications protocol, LAN, NetBIOS.

NetBIOS n. An application programming interface (API) that can be used by application programs on a local area network consisting of IBM and compatible microcomputers running MS-DOS, OS/2, or some version of UNIX. Primarily of interest to programmers, NetBIOS provides application programs with a uniform set of commands for requesting the lower-level network services required to conduct sessions between nodes on a network and to transmit information back and forth. See also application programming interface.

NetBIOS Extended User Interface n. See NetBEUI.

net boot n. See PXE boot.

NetBSD n. A free version of the BSD UNIX operating system developed as a result of a volunteer effort. NetBSD is highly interoperable, runs on many hardware platforms, and is nearly POSIX compliant. See also BSD UNIX, POSIX.

Netcaster n. See netcasting (definition 2).

netcasting n. 1. Synonym for webcasting. 2. A Netscape technology used in Netscape Netcaster that enabled a user to subscribe to channels that pushed Web content to the user s desktop without actively retrieving the information. Netscape Netcaster, which was part of previous versions of Netscape Navigator, competed with Microsoft Active Desktop. Unlike Active Desktop, which uses Microsoft s Channel Definition Format (CDF), the Netcaster push client was based on existing open standards (HTML, Java, and JavaScript). See also push (definition 2). Compare Active Desktop.

.NET Compact Framework n. A hardware-independent environment for running programs on resource-constrained computing devices. It inherits the full .NET Framework architecture of the common language runtime, supports a subset of the .NET Framework class library, and contains classes designed exclusively for the .NET Compact Framework. Supported devices include personal data assistants (PDAs) (such as the Pocket PC), mobile phones, set-top boxes, automotive computing devices, and custom-designed embedded devices built with the Microsoft Windows CE operating system.

.NET data provider n. A component of ADO.NET that provides access to data from a relational database.

netfilter n. The packet-filtering system for Linux introduced in the 2.4 kernel. Netfilter is the first stateful firewall implemented in Linux. See also firewall, iptables. Compare IP Filter.

NetFind n. See AOL NetFind.

.NET Framework n. A platform for building, deploying, and running XML Web services and applications. It provides a highly productive, standards-based, multilanguage environment for integrating existing investments with next generation applications and services, as well as the agility to solve the challenges of deployment and operation of Internet-scale applications. The .NET Framework consists of three main parts: the common language runtime, a hierarchical set of unified class libraries, and a componentized version of ASP called ASP.NET. See also ASP.NET, common language runtime, .NET Framework class library.

.NET Framework class library n. A Common Language Specification (CLS) compliant library of classes, interfaces, and value types that are included in the Microsoft .NET Framework SDK. This library provides access to system functionality and is designed to be the foundation on which .NET Framework applications, components, and controls are built.

.NET Framework data provider n. A component of ADO.NET that provides access to data from a relational data source. A .NET Framework data provider contains classes to connect to a data source, execute commands at the data source, and return query results from the data source, including the ability to execute commands within transactions. A .NET Framework data provider also contains classes to populate a DataSet with results from a data source and propagate changes in a DataSet back to the data source.

net.god n. A highly respected person within the Internet community.

nethead n. 1. A person who uses the Internet as if addicted to it. 2. A Grateful Dead fan who participates in the rec.music.gdead newsgroup or some other forum dedicated to that band.

netiquette n. Short for network etiquette. Principles of courtesy observed in sending electronic messages, such as e-mail and Usenet postings. The consequences of violating netiquette include being flamed and having one s name placed in the bozo filter of one s intended audience. Disapproved behavior includes gratuitous personal insults; posting of large amounts of irrelevant material; giving away the plot of a movie, television show, or novel without warning; posting offensive material without encrypting it; and excessive cross-posting of a message to multiple groups without regard to whether the group members are likely to find it interesting. See also bozo filter, flame².

netizen n. A person who participates in online communication through the Internet and other networks, especially conference and chat services, such as Internet news or Fidonet. Compare lurker.

NetMeeting n. A software application developed by Microsoft Corporation to allow video conferencing among parties using personal computers connected via the Internet. NetMeeting allows participants in different locations to view each other, engage in text chat conversations, send and receive videos, exchange information graphically via an electronic whiteboard, share Windows-based applications, and transfer files.

.NET Messenger Service n. A popular instant-messaging service provided by Microsoft as part of the .NET strategy. With .NET Messenger Service, formerly called MSN Messenger Service, users can communicate using the Windows Messenger, included in Windows XP, or MSN Messenger applications. See also instant messaging. Compare AIM, ICQ, Yahoo! Messenger.

.NET My Services n. A suite of XML Web services for managing and protecting personal information and interactions across applications, devices, and services. Formerly code-named HailStorm, .NET My Services is based on the Microsoft .NET Passport user-authentication system. The suite of .NET My Services includes services such as .NET ApplicationSettings, .NET Calendar, .NET Contacts, .NET Devices, .NET Documents, .NET Inbox, .NET Locations, .NET Profile, and .NET Wallet. See also .NET, Passport.

NetPC n. Short for Network PC. An industry-defined, Windows-based PC system that is small and meant to act as simply an access point. These PCs generally have very small hard drives, no disk drives, and are built to have a very low cost. Some older NetPCs can boot through remote access to a server and user server-based resources for most computing actions.

net.personality n. A slang term for a person who has attained some degree of celebrity on the Internet.

net.police n. Persons (usually self-appointed) who try to enforce their understanding of the rules that apply to conduct on the Internet. Their activities may be directed toward users who violate the rules of netiquette, spammers who send unsolicited advertising as e-mail or to newsgroups, or even people who post politically incorrect comments to newsgroups or mailing lists. See also netiquette, spam.

Netscape Navigator n. The widely used family of Web browser programs, made by Netscape Corporation. Versions of Netscape Navigator are available for the Windows and Macintosh platforms, and for many varieties of UNIX. Netscape Navigator, which is based on NCSA s Mosaic Web browser, was one of the first commercially available Web browsers. In 1999, Netscape Corporation was purchased by America Online. See also Mosaic, Web browser.

Netscape Netcaster n. See netcasting (definition 2).

Netscape Server Application Programming Interface n. See NSAPI.

Netspeak n. The set of conventions for writing English in e-mail, IRCs, and newsgroups. Netspeak is characterized by acronyms (such as IMHO or ROFL) and clarifying devices such as emotags and emoticons. Use of Netspeak should be governed by netiquette. See also emotag, emoticon, IMHO, IRC, netiquette, ROFL.

netspionage n. Corporate-sponsored hacking of a competitor s digital information for the theft of trade secrets.

Net surfing n. The practice of exploring the Internet without a specific goal in mind. The concept of Net surfing is similar to (and probably derived from) channel surfing in reference to watching television.

Net TV n. See Internet television.

NetWare n. A family of LAN (local area network) operating system products developed by Novell, Inc. Designed to run on PCs and Macintoshes, Novell NetWare allows users to share files and system resources such as hard disks and printers. See also network operating system.

network n. A group of computers and associated devices that are connected by communications facilities. A network can involve permanent connections, such as cables, or temporary connections made through telephone or other communication links. A network can be as small as a LAN (local area network) consisting of a few computers, printers, and other devices, or it can consist of many small and large computers distributed over a vast geographic area (WAN, or wide area network). See also ALOHAnet, Ethernet (definition 1), LAN, WAN.

Network Access Point n. One of the interchange points for Internet traffic, where various Internet network carriers and major ISPs exchange data. When Internet traffic originates on one network and goes to another network, it almost always passes through at least one Network Access Point, or NAP. In the United States, major NAPs include MAE East, in Vienna, Virginia, and MAE West, in San Jose, California (both operated by MCI WorldCom); the Chicago NAP (operated by Ameritech); the Pacific Bell NAP (with multiple locations in California); the Digital Internet Exchange in Palo Alto, California (operated by Digital/Compaq); and the Sprint NAP in Pennsauken, New Jersey. Additional local and regional exchange points are located in many other locations around the world. Acronym: NAP. Also called: National Attachment Point.

network adapter n. See network interface card.

Network Address Translation n. See NAT.

network administrator n. The person in charge of operations on a computer network. The duties of a network administrator can be broad and might include such tasks as installing new workstations and other devices, adding and removing individuals from the list of authorized users, archiving files, overseeing password protection and other security measures, monitoring usage of shared resources, and handling malfunctioning equipment. See also system administrator.

network architecture n. The underlying structure of a computer network, including hardware, functional layers, interfaces, and protocols, used to establish communication and ensure the reliable transfer of information. Network architectures are designed to provide both philosophical and physical standards for the complexities of establishing communications links and transferring information without conflict. Various network architectures exist, including the internationally accepted seven-layer ISO Open Systems Interconnection (OSI) model and IBM s Systems Network Architecture (SNA). See also ISO/OSI reference model, SNA.

Network-Attached Storage n. See NAS.

network boot n. See PXE boot.

network card n. See network interface card.

network-centric computing n. A computing environment in which a network server or servers represent the hub of activity. Considered the third wave in large-system computing after mainframe and desktop developments, network-centric computing establishes servers as the main source of computing power, to give users direct access to network-based applications and information. In network-centric computing systems, applications are not preinstalled or uninstalled locally, that is, on the desktop; they are accessed on an as-needed, on-the-fly basis. Thus, individual desktop computers do not have to maintain large amounts of disk storage or load and manage application programs. See also server.

network computer n. A computer designed for use on a network in which programs and storage are provided by servers. Network computers, unlike dumb terminals, have their own processing power, but their design does not include local storage and they depend on network servers for applications. Acronym: NC.

network congestion n. See congestion.

network connection n. See Ethernet.

network control program n. In a communications network that includes a mainframe computer, a program that usually resides in a communications controller and takes over communications tasks such as routing, error control, line control, and polling (checking terminals for transmissions), leaving the main computer free for other functions. See also communications controller.

Network Control Protocol n. See Point-to-Point Protocol.

network database n. 1. A database that runs in a network. 2. A database containing the address of other users in the network. 3. In information management, a type of database in which data records can be related to one another in more than one way. A network database is similar to a hierarchical database in the sense that it contains a progression from one record to another. It differs in being less rigidly structured: any single record can point to more than one other record and, conversely, can be pointed to by one or more records. In effect, a network database allows more than one path between any two records, whereas a hierarchical database allows only one, from parent (higher-level record) to child (lower-level record). Compare hierarchical database, relational database.

Network Data Management Protocol n. See NDMP.

network device driver n. Software that coordinates communication between the network adapter card and the computer s hardware and other software, controlling the physical function of the network adapter card.

network directory n. On a local area network, a directory on a disk that is located on a computer other than the one the user is operating. A network directory differs from a network drive in that the user has access to only that directory. Whether the rest of the disk is accessible to the user depends on whether he or she has been granted access rights by the network administrator. On the Macintosh, a network directory is referred to as a shared folder. Also called: networked directory, shared directory. See also network drive, shared folder.

network drive n. On a local area network, a disk drive whose disk is available to other computers on the network. Access to a network drive might not be allowed to all users of the network; many operating systems contain security provisions that enable a network administrator to grant or deny access to part or all of a network drive. Also called: networked drive. See also network directory.

Network Driver Interface Specification n. See NDIS.

networked directory n. See network directory.

networked drive n. See network drive.

networked home n. See smart home.

Network File System n. See NFS.

network information center n. See NIC (definition 2).

network interface card n. An expansion card or other device used to provide network access to a computer or other device, such as a printer. Network interface cards mediate between the computer and the physical media, such as cabling, over which transmissions travel. Acronym: NIC. Also called: network adapter, network card.

Network Kernel Extension n. See NKE.

network latency n. The time it takes for information to be transferred between computers in a network.

network layer n. The third of the seven layers in the ISO/OSI reference model for standardizing computer-to-computer communications. The network layer is one level above the data-link layer and ensures that information arrives at its intended destination. It is the middle of the three layers (data-link, network, and transport) concerned with the actual movement of information from one device to another. See the illustration. See also ISO/OSI reference model.

Network layer.

network meltdown n. See broadcast storm, meltdown.

network model n. A database structure, or layout, similar to a hierarchical model, except that records can have multiple parent records as well as multiple child records. A database management system that supports a network model can be used to simulate a hierarchical model. See also CODASYL, network database (definition 3). Compare hierarchical model.

network modem n. A modem that is shared by users of a network for calling an online service provider, an ISP, a service bureau, or other online source. See also ISP, modem, online information service, service bureau (definition 2).

network news n. The newsgroups on the Internet, especially those in the Usenet hierarchy.

Network News Transfer Protocol n. See NNTP.

network operating system n. An operating system specifically designed to support networking. A server-based network operating system provides networking support for multiple simultaneous users as well as administrative, security, and management functions. On the desktop, a network-aware operating system provides users with the ability to access network resources. Unlike a single-user operating system, a network operating system must acknowledge and respond to requests from many workstations, managing such details as network access and communications, resource allocation and sharing, data protection, and error control. Acronym: NOS. Also called: network OS.

network operation center n. The office in an enterprise that is responsible for maintaining network integrity and improving network efficiency while reducing system downtime. Acronym: NOC.

network OS n. See network operating system.

network protocol n. A set of rules and parameters that defines and enables communication through a network.

Network Query Language n. A scripting language for controlling intelligent agents for Web applications. Acronym: NQL.

network server n. See server.

network services n. 1. In a corporate environment, the division that maintains the network and the computers. 2. In a Windows environment, extensions to the operating system that allow it to perform network functions such as network printing and file sharing.

network software n. Software including a component that facilitates connection to or participation in a network.

Network Solutions, Inc. n. See NSI.

network structure n. The record organization used in a particular network model.

Network Terminator 1 n. An ISDN device that acts as an interface between an ISDN telephone line and one or more terminal adapters or terminal devices, such as an ISDN telephone. Acronym: NT-1. See also ISDN, ISDN terminal adapter.

Network Time Protocol n. An Internet protocol used to synchronize the clocks in computers connected to the Internet. Acronym: NTP. See also communications protocol.

network topology n. See topology.

network weaving n. See leapfrog attack.

NetWorld+Interop n. International conference and exhibition for the networking and information technology industry. NetWorld+Interop draws attendees from a variety of industries, including telecommunications, Internet services, and e-commerce. NetWorld+Interop features product exhibits, educational conferences, tutorials, and workshops.

NeuralCast Technology n. Technology developed by RealNetworks to improve the transmission of digital media over RealNetworks servers. NeuralCast Technology uses a variety of protocols, introduces new techniques to correct errors in streaming signals, and uses telephone and satellite transmissions to coordinate server networks to optimize digital media transmission.

neural network n. A type of artificial-intelligence system modeled after the neurons (nerve cells) in a biological nervous system and intended to simulate the way a brain processes information, learns, and remembers. A neural network is designed as an interconnected system of processing elements, each with a limited number of inputs and an output. These processing elements are able to learn by receiving weighted inputs that, with adjustment, time, and repetition, can be made to produce appropriate outputs. Neural networks are used in areas such as pattern recognition, speech analysis, and speech synthesis. See also artificial intelligence (definition 1), pattern recognition.

newbie n. 1. An inexperienced user on the Internet. 2. In a particularly derogatory sense, an inexperienced Usenet user who asks for information that is readily available in the FAQ. See also FAQ.

newline character n. A control character that causes the cursor on a display or the printing mechanism on a printer to move to the beginning of the next line. It is functionally equivalent to a combination of the carriage return (CR) and linefeed (LF) characters. Acronym: NL. See also carriage return, linefeed.

news n. The Internet protocol for retrieving files from an Internet newsgroup. You can create hyperlinks to newsgroups using news://.

news.announce.newusers n. A newsgroup that contains general information for new users about using Internet newsgroups.

newsfeed or news feed n. Deliveries, exchanges, or distributions of newsgroup articles to and from news servers. Newsfeeds are accomplished through cooperating news servers, which communicate via NNTP through network connections. Also called: feed. See also newsgroup, news server, NNTP.

newsgroup n. A forum on the Internet for threaded discussions on a specified range of subjects. A newsgroup consists of articles and follow-up posts. An article with all of its follow-up posts which are (supposed to be) related to the specific subject named in the original article s subject line constitutes a thread. Each newsgroup has a name that consists of a series of words, separated by periods, indicating the newsgroup s subject in terms of increasingly narrow categories, such as rec.crafts.textiles.needlework. Some newsgroups can be read and posted to only on one site; others, such as those in the seven Usenet hierarchies or those in ClariNet, circulate throughout the Internet. See also article, bit. newsgroups, ClariNet, follow-up, Great Renaming, local newsgroups, mail reflector, threaded discussion, traditional newsgroup hierarchy, Usenet. Compare mailing list.

newsmaster n. The person in charge of maintaining the Internet news server at a particular host. Sending e-mail to [e-mail] is the standard way to reach a given newsmaster.

news. newsgroups n. Usenet newsgroups that are part of the news. hierarchy and begin with news. These newsgroups cover topics that deal with Usenet itself, such as Usenet policy and the creation of new Usenet newsgroups. See also newsgroup, traditional newsgroup hierarchy, Usenet. Compare comp. newsgroups, misc. newsgroups, rec. newsgroups, sci. newsgroups, soc. newsgroups, talk. newsgroups.

.newsrc n. The file extension that identifies a setup file for UNIX-based newsreaders. The setup file typically contains a current list of newsgroups that the user subscribes to and the articles in each newsgroup that the user has already read. See also newsreader, setup (definition 2).

newsreader n. A Usenet client program that enables a user to subscribe to Usenet newsgroups, read articles, post follow-ups, reply by e-mail, and post articles. Many Web browsers also provide these functions. See also article, e-mail (definition 1), follow-up, newsgroup, Usenet, Web browser.

news server n. A computer or program that exchanges Internet newsgroups with newsreader clients and other servers. See also newsgroup, newsreader.

Newton n. A personal digital assistant (PDA) developed by Apple Computer, Inc. See also PDA.

Newton OS n. The operating system that controls the Newton MessagePad personal digital assistant (PDA). See also PDA.

NeXT n. A computer designed and produced by NeXT Computer, Inc. (later NeXT Software, Inc.), a computer manufacturer and software developer founded in 1985 by Steven Jobs. NeXT was purchased by Apple Computer in 1997.

Next Generation Internet n. An initiative funded by the U.S. federal government designed to develop faster, more powerful networking technologies than are available on the current global Internet. The Next Generation Internet, or NGI, was begun in 1997 under the auspices of a number of government agencies, including DARPA (Defense Advanced Research Projects Agency), NASA (National Aeronautics & Space Administration), and the NSF (National Science Foundation). Its objective is to develop advanced networking technologies and to demonstrate them on university and government test networks running 100 to 1000 times faster than the current Internet. The technologies developed are intended for eventual use by schools, businesses, and the general public. Acronym: NGI. Compare Internet, Internet2.

NFS n. Acronym for Network File System. A distributed file system that allows users to access remote files and directories on a network as if they were local. NFS is compatible with Microsoft Windows and UNIX-based systems, including Linux and Mac OS X.

NGI n. See Next Generation Internet.

nibble or nybble n. Half a byte (4 bits). Compare quadbit.

NIC n. 1. See network interface card. 2. Acronym for network information center. An organization that provides information about a network and other support to users of the network. The principal NIC for the Internet is InterNIC. Intranets and other private networks may have their own NICs. See also InterNIC.

NiCad battery n. See nickel cadmium battery.

NIC handle n. See handle.

nickel cadmium battery n. A rechargeable battery that uses an alkaline electrolyte. Nickel cadmium batteries typically have a longer operating life and storage life than similar lead-acid batteries. Also called: NiCad battery. Compare lead ion battery, lithium ion battery, nickel metal hydride battery.

nickel metal hydride battery n. A rechargeable battery that offers longer life and superior performance compared with similar nickel cadmium or other alkaline batteries. Also called: NiMH battery. Compare lead ion battery, lithium ion battery, nickel cadmium battery.

nickname n. A name used in the destination field of an e-mail editor in place of one or more complete network addresses. For example Fred might be a nickname for [e-mail]. If the nickname has been established within the program, a user need only type Fred instead of the entire address, or perhaps history faculty instead of all the individual faculty addresses. See also alias (definition 2).

NIDS n. Acronym for network-based intrusion-detection System. A type of intrusion detection system (IDS) that analyzes the individual packets moving across a network. NIDS can detect packets that a firewall might not catch. See also IDS.

NII n. See National Information Infrastructure.

nil pointer n. See null pointer.

Nimda worm n. A persistent worm that can slow or freeze mail servers, take control of Web pages, and infect systems through several different means. The Nimda worm spreads as an attached file through e-mail, through an Internet scan for vulnerable Web servers, through a Java Script on an infected Web page, or through network sharing. The Nimda worm first appeared in 2001, with several variants following the original version.

NiMH battery n. See nickel metal hydride battery.

nine s complement n. A number in the base-10 (decimal) system that is the complement of another number. It is derived by subtracting each digit of the number to be complemented from 1 less than the base. For example, the nine s complement of 64 is 35 the number derived by subtracting 6 from 9 and 4 from 9. See also complement.

NIS n. Acronym for Network Information Service. See Yellow Pages (definition 1).

NIST n. See National Institute of Standards and Technology.

*NIX n. Slang for any UNIX-related operating system, or all UNIX-related operating systems. *NIX typically refers to UNIX and Linux, and may also include Mac OS X.

nixpub n. A list of ISPs (Internet service providers) available in the newsgroups comp.bbs.misc and alt.bbs. See also ISP.

NKE n. Acronym for Network Kernel Extension. A modification or extension of the Mac OS X networking infrastructure. NKEs may be loaded or unloaded dynamically, without recompiling the kernel or without the need to reboot the system. NKEs allow the creation and configuration of protocol stacks and modules that may monitor or modify network traffic or add other networking features to the kernel.

NL n. See newline character.

NLQ n. See near-letter-quality.

NLS n. See natural language support.

NMI n. See nonmaskable interrupt.

NMOS or N-MOS n. Acronym for N-channel metal-oxide semiconductor. A semiconductor technology in which the conduction channel in MOSFETs is formed by the movement of electrons rather than holes (electron vacancies created as electrons move from atom to atom). Because electrons move faster than holes, NMOS is faster than PMOS, although it is more difficult and more expensive to fabricate. See also MOS, MOSFET, N-type semiconductor. Compare CMOS, PMOS.

NNTP n. Acronym for Network News Transfer Protocol. A de facto protocol standard on the Internet used to distribute news articles and query news servers.

NOC n. See network operation center.

node n. 1. A junction of some type. 2. In networking, a device, such as a client computer, a server, or a shared printer, that is connected to the network and is capable of communicating with other network devices. 3. In tree structures, a location on the tree that can have links to one or more nodes below it. Some authors make a distinction between node and element, with an element being a given data type and a node comprising one or more elements as well as any supporting data structures. See also element (definition 1), graph, pointer (definition 1), queue, stack, tree.

noise n. 1. Any interference that affects the operation of a device. 2. Unwanted electrical signals, produced either naturally or by the circuitry, that distort or degrade the quality or performance of a communications channel. See also distortion.

nonbreaking space n. A character that replaces the standard space character in order to keep two words together on one line rather than allowing a line to break between them.

noncompetes n. An agreement between employer and employee that states that the employee will not accept work with a competing company for a specified length of time after leaving the employer s company. Noncompete agreements are common in high-tech companies and are typically requested to help maintain company secrets and retain valuable employees.

nonconductor n. See insulator.

noncontiguous data structure n. In programming, a data structure whose elements are not stored contiguously in memory. Data structures such as graphs and trees, whose elements are connected by pointers, are noncontiguous data structures. Compare contiguous data structure.

nondedicated server n. A computer on a network that can function as both a client and a server; typically, a desktop machine on a peer-to-peer network. Compare dedicated server.

nondestructive readout n. A reading operation that does not destroy the data read, either because the storage technology is capable of retaining the data or because the reading operation is accompanied by a data refresh (update) function. Acronym: NDR, NDRO. Compare destructive read.

nonexecutable statement n. 1. A program statement that cannot be executed because it lies outside the flow of execution through the program. For example, a statement immediately following a return() statement but before the end of the block in C is nonexecutable. 2. A type definition, variable declaration, preprocessor command, comment, or other statement in a program that is not translated into executable machine code.

nonimpact printer n. Any printer that makes marks on the paper without striking it mechanically. The most common types are ink-jet, thermal, and laser printers. See also ink-jet printer, laser printer, thermal printer. Compare impact printer.

noninterlaced adj. Pertaining to a display method on raster-scan monitors in which the electron beam scans each line of the screen once during each refresh cycle. Compare interlaced.

nonmaskable interrupt n. A hardware interrupt that bypasses and takes priority over interrupt requests generated by software and by the keyboard and other such devices. A nonmaskable interrupt cannot be overruled (masked) by another service request and is issued to the microprocessor only in disastrous circumstances, such as severe memory errors or impending power failures. Acronym: NMI. Compare maskable interrupt.

nonprocedural language n. A programming language that does not follow the procedural paradigm of executing statements, subroutine calls, and control structures sequentially but instead describes a set of facts and relationships and then is queried for specific results. Compare procedural language.

nonreturn to zero n. 1. In data transmission, a method of encoding data in which the signal representing binary digits alternates between positive and negative voltage when there is a change in digits from 1 to 0 or vice versa. In other words, the signal does not return to a zero, or neutral, level after transmission of each bit. Timing is used to distinguish one bit from the next. 2. In the recording of data on a magnetic surface, a method in which one magnetic state represents a 1 and, usually, the opposite state represents a 0. Acronym: NRZ.

nontrivial adj. Being either difficult or particularly meaningful. For example, a complicated programmed procedure to handle a difficult problem would represent a nontrivial solution.

Non-Uniform Memory Access n. See NUMA.

nonuniform memory architecture n. A system architecture designed for Sequent s Non-Uniform Access Memory, a type of distributed shared memory using a number of shared memory segments instead of a single centralized physical memory. Acronym: NUMA.

nonvolatile memory n. A storage system that does not lose data when power is removed from it. Intended to refer to core memory, ROM, EPROM, flash memory, bubble memory, or battery-backed CMOS RAM, the term is occasionally used in reference to disk subsystems as well. See also bubble memory, CMOS RAM, core, EPROM, flash memory, ROM.

NO-OP n. See no-operation instruction.

no-operation instruction n. A machine instruction that has no results other than to cause the processor to use up clock cycles. Such instructions are useful in certain situations, such as padding out timing loops or forcing subsequent instructions to align on certain memory boundaries. Acronym: NO-OP, NOP. See also machine instruction.

NOP n. See no-operation instruction.

NOR gate n. Short for NOT OR gate. A digital circuit whose output is true (1) only if all inputs are false (0). A NOR gate is an OR circuit (output with the value of 1 if any input value is 1) followed by a NOT circuit (output that is the logical complement of the input). See also gate (definition 1), NOT gate, OR gate.

normal distribution n. In statistics, a type of function that describes the probabilities of the possible values of a random variable. The function, whose graph is the familiar bell-shaped curve, can be used to determine the probability that the value of the variable will fall within a particular interval of values.

normal form n. 1. In a relational database, an approach to structuring (organizing) information in order to avoid redundancy and inconsistency and to promote efficient maintenance, storage, and updating. Several rules or levels of normalization are accepted, each a refinement of the preceding one. Of these, three forms are commonly used: first normal (1NF), second normal (2NF), and third normal (3NF). First normal forms, the least structured, are groups of records (such as employee lists) in which each field (column) contains unique and nonrepeating information. Second and third normal forms break down first normal forms, separating them into different tables by defining successively finer interrelationships between fields. Second normal forms do not include fields that are subsets of fields other than the primary (key) field; for example, a second normal form keyed to employee name would not include both job grade and hourly rate if pay were dependent on job grade. Third normal forms do not include fields that provide information about fields other than the key field; for example, a third normal form keyed to employee name would not include project name, crew number, and supervisor unless the crew number and supervisor were assigned only to the project the employee was working on. Further normalization refinements include Boyce-Codd Normal Form (BCNF), fourth normal form (4NF), and projection-join (or fifth) normal form (PJ/NF or 5NF). These levels, however, are not as commonly used as the first, second, and third normal forms. 2. In programming, the metalanguage sometimes called the Backus normal form (Backus-Naur form) a language used for describing the syntax of other languages, specifically ALGOL 60, for which it was invented. See also Backus-Naur form.

normal hyphen n. See hyphen.

normalize vb. 1. In programming, to adjust the fixed-point and exponent portions of a floating-point number to bring the fixed-point portions within a specific range. 2. In database management, to apply a body of techniques to a relational database in order to minimize the inclusion of duplicate information. Normalization greatly simplifies query and update management, including security and integrity considerations, although it does so at the expense of creating a larger number of tables. See also normal form (definition 1).

North American Cellular Network n. Telecommunications network that enables wireless phone users in North America to send and receive calls when roaming outside their service area. Acronym: NACN.

NOS n. See network operating system.

NOT n. An operator that performs Boolean or logical negation. See also Boolean operator, logical operator.

NOT AND n. See NAND.

notation n. In programming, the set of symbols and formats used to describe the elements of programming, mathematics, or a scientific field. A language s syntax is defined in part by notation. See also syntax.

notebook computer n. See portable computer.

NOT gate n. One of the three basic logic gates (with AND and OR) from which all digital systems can be built. The NOT circuit, also referred to as an inverter, has output that is the reverse of its input that is, the output is true (1) if the input is false (0) and false (0) if the input is true (1). See also AND gate, gate (definition 1), OR gate.

notification n. A signal from the operating system that an event has occurred.

Novell Directory Services n. See NDS.

Novell NetWare n. See NetWare.

NPN transistor n. A type of transistor in which a base of P-type material is sandwiched between an emitter and a collector of N-type material. The base, emitter, and collector are the three terminals through which current flows. In an NPN transistor, electrons represent the majority of the charge carriers, and they flow from the emitter to the collector. See the illustration. See also N-type semiconductor, P-type semiconductor. Compare PNP transistor.

NPN transistor.

NQL n. See Network Query Language.

NRZ n. See nonreturn to zero.

ns n. See nanosecond.

NSAPI n. Acronym for Netscape Server Application Programming Interface. A specification for interfaces between the Netscape HTTP server and other application programs. NSAPI can be used to provide access to application programs from a Web browser through a Web server. See also HTTP server (definition 1), Web browser.

NSF n. See National Science Foundation.

NSFnet n. Short for the National Science Foundation Network. A WAN (wide area network), developed by the National Science Foundation to replace ARPANET for civilian purposes. NSFnet served as a major backbone for the Internet until mid-1995. Backbone services in the United States for the Internet are now provided by commercial carriers. See also ARPANET, backbone (definition 1).

NSFnet Network Information Center n. See InterNIC.

NSI n. Acronym for Network Solutions, Inc. The organization responsible, since 1992, for registering top-level Internet domain names and maintaining the authoritative ( A ) database of top-level domains replicated daily on 12 other root servers on the Internet. In 1998, with the privatization of Internet administration, the functions performed by NSI (under cooperative agreement with the U.S. National Science Foundation) became the responsibility of ICANN, a new, nonprofit organization. NSI remains active, but its association with the U.S. government entered the ramping down phase in 1998/1999. See also IANA, ICANN.

NT n. See Windows NT.

NT-1 n. See Network Terminator 1.

NT file system n. See NTFS.

NTFS n. Acronym for NT file system. An advanced file system designed for use specifically with the Windows NT operating system. It supports long filenames, full security access control, file system recovery, extremely large storage media, and various features for the Windows NT POSIX subsystem. It also supports object-oriented applications by treating all files as objects with user-defined and system-defined attributes. See also FAT file system, HPFS, POSIX.

NTLM authentication protocol n. A challenge/response authentication protocol. The NTLM authentication protocol was the default for network authentication in Windows NT version 4.0 and earlier and Windows Millennium Edition (Windows Me) and earlier. The protocol continues to be supported in Windows 2000 and Windows XP but no longer is the default. See also Kerberos.

NTP n. Acronym for Network Time Protocol. A protocol used for synchronizing the system time on a computer to that of a server or other reference source such as a radio, satellite receiver, or modem. NTP provides time accuracy within a millisecond on local area networks and a few tens of milliseconds on wide area networks. NTP configurations may utilize redundant servers, diverse network paths, and cryptographic authentication to achieve high accuracy and reliability.

NTSC n. Acronym for National Television System (later changed to Standards) Committee. The standards-setting body for television and video in the United States. It is the sponsor of the NTSC standard for encoding color, a coding system compatible with black-and-white signals and the system used for color broadcasting in the United States.

N-type semiconductor n. Semiconductor material in which electrical conduction is carried by electrons, in contrast to P-type semiconductors, in which conduction is carried by holes that is, electron vacancies. N-type semiconductors are created by adding a dopant with an excess of electrons during the manufacturing process. See also semiconductor. Compare P-type semiconductor.

NuBus n. A high-performance expansion bus used in Macintosh computers, offering high bandwidth and multiple bus controllers. Invented at the Massachusetts Institute of Technology (MIT), NuBus was eventually licensed to Texas Instruments and other companies. See also bus.

nudge vb. To move an object one pixel at a time.

nuke vb. 1. To erase a file, directory, or entire hard disk. 2. To stop a process in an operating system, an application, or a program. Also called: kill.

NUL n. 1. A character code with a null value; literally, a character meaning nothing. Although it is real in the sense of being recognizable, occupying space internally in the computer, and being sent or received as a character, a NUL character displays nothing, takes no space on the screen or on paper, and causes no specific action when sent to a printer. In ASCII, NUL is represented by the character code 0. See also ASCII. 2. A device, recognized by the operating system, that can be addressed like a physical output device (such as a printer) but that discards any information sent to it.

null character n. See NUL.

null cycle n. The shortest amount of time required for execution of a program; the time needed to cycle through the program without requiring it to process new data or loop through sets of instructions.

null modem n. A way of connecting two computers via a cable that enables them to communicate without the use of modems. A null modem cable accomplishes this by crossing the sending and receiving wires so that the wire used for transmitting by one device is used for receiving by the other and vice versa. See the illustration.

Null modem. Null modem cable-wiring schematics for IBM PC-compatible computers.

null modem cable n. A serial data cable used to connect two personal computers, without a modem or other DCE device in between, through the computers serial ports. Because both computers use the same pins to send data, a null modem cable connects the output pins in one computer s serial port to the input pins in the other. A null modem cable is used to transfer data between two personal computers in close proximity. See also serial port.

null pointer n. A pointer to nothing usually a standardized memory address, such as 0. A null pointer usually marks the last of a linear sequence of pointers or indicates that a data search operation has come up empty. Also called: nil pointer. See also pointer (definition 1).

null string n. A string containing no characters; a string whose length is zero. See also string.

null-terminated string n. See ASCIIZ string.

NUMA n. Acronym for Non-Uniform Memory Access. A multiprocessing architecture that manages memory according to its distance from the processor. Banks of memory at various distances require different amounts of access time, with local memory accessed faster than remote memory. See also SMP.

number cruncher n. 1. A computer that is able to quickly perform large amounts of mathematical computations. 2. A powerful workstation. 3. A program whose main task is to perform mathematical computations for example, a statistical program. 4. A person who uses a computer to analyze numbers.

number crunching vb. The calculation of large amounts of numeric data. Number crunching can be repetitive, mathematically complex, or both, and it generally involves far more internal processing than input or output functions. Numeric coprocessors greatly enhance the ability of computers to perform these tasks.

numerical analysis n. The branch of mathematics devoted to finding ways to solve abstract mathematical problems and finding concrete or approximate solutions for them.

numeric coprocessor n. See floating-point processor.

numeric keypad n. A calculator-style block of keys, usually at the right side of a keyboard, that can be used to enter numbers. In addition to keys for the digits 0 through 9 and keys for indicating addition, subtraction, multiplication, and division, a numeric keypad often includes an Enter key (usually not the same as the Enter or Return key on the main part of the keyboard). On Apple keyboards, the numeric keypad also includes a Clear key that usually functions like the Backspace key for deleting characters. In addition, many of the keys can serve dual purposes, such as cursor movement, scrolling, or editing tasks, depending on the status of the Num Lock key. See the illustration. See also Num Lock key.

Numeric keypad.

numeric messaging n. Service that enables wireless phones and pagers to receive messages consisting only of numeric information, such as phone numbers.

numeric paging n. See numeric messaging.

Num Lock key n. Short for Numeric Lock key. A toggle key that, when turned on, activates the numeric keypad so that its keys can be used for calculator-style data entry. When the Num Lock key is toggled off, most of the numeric keypad keys are used for cursor movement and on-screen scrolling. See also numeric keypad.

NVM n. Acronym for Non-Volatile Memory. Memory that persists in its state when the power is removed. Also called: Flash memory.

NVRAM n. Acronym for Non-Volatile Random Access Memory. Non-volatile read/write memory or normally volatile memory that has been fitted with a battery backup to retain data. See also NVM.

NWLink n. An implementation of the Internetwork Packet Exchange (IPX), Sequenced Packet Exchange (SPX), and NetBIOS protocols used in Novell networks. NWLink is a standard network protocol that supports routing and can support NetWare client-server applications, where NetWare-aware Sockets-based applications communicate with IPX/SPX Sockets-based applications. See also IPX/SPX, NetBIOS, RIPX.

nybble n. See nibble.