Return to List of Terms

MAC
A popular model of computer made by Apple Computer. Introduced in 1984, the Macintosh features a graphical user interface (GUI) that utilises window, icon, and a mouse to make it relatively easy for novices to use the computer productively. Rather than learning a complex set of commands, you need only point to a selection on a menu and click a mouse button.

MAC Address
Media Access Control address, a hardware address that uniquely identifies each node of a network. In IEEE 802 networks, the Data Link Control (DLC) layer of the OSI Reference Model is divided into two sublayers: the Logical Link Control (LLC) layer and the Media Access Control (MAC) layer. The MAC layer interfaces directly with the network media.

MalWare
Short for MALicious softWARE, is programming or files that are developed for the purpose of doing harm.

MAPI
Messaging Application Programming Interface, a system built into Microsoft Windows that enables different e-mail applications to work together to distribute mail. As long as both applications are MAPI-enabled, they can share mail messages with each other.

MAN
Metropolitan Area Network, is a network that interconnects users with computer resources in a geographic area or region larger than that covered by even a large LAN but smaller than the area covered by a WAN.

MAU
(1) Media Access Unit, an Ethernet transceiver.

(2) Multistation Access Unit (also abbreviated as MSAU), a token-ring network device that physically connects network computers in a star topology while retaining the logical ring structure. One of the problems with the token-ring topology is that a single non-operating node can break the ring. The MAU solves this problem because it has the ability to short out non-operating nodes and maintain the ring structure. A MAU is a special type of hub.

Mbone
Multicast Backbone, on the Internet. MBone is an extension to the Internet to support IP multicasting.

MDA
(1) Mail Delivery Agent.

(2) Monochrome Display Adaptor.

Megabyte
A collection of 1,024 Kilobytes.

Meta Refresh
Refers to HTML coding that redirects a Web site visitor to a new page after a set and specified number of seconds. Meta refresh tags are used by Web sites that have changed addresses but want visitors to be able to access the new URLURL by going through the old one. When a user is automatically brought to a new page, this is known as redirection.

Meta Tags
A special HTML tag that provides information about a Web page. Unlike normal HTML tags, meta tags do not affect how the page is displayed. Instead, they provide information such as who created the page, how often it is updated, what the page is about, and which keywords represent the page's content. Many search engines use this information when building their indices.

MIB
Management Information Base, a database of objects that can be monitored by a network management system. Both SNMP and RMON use standardised MIB formats that allows any SNMP and RMON tools to monitor any device defined by a MIB.

MIDI
Musical Instrument Digital Interface, a standard adopted by the electronic music industry for controlling devices, such as synthesizers and sound cards, that emit music. At minimum, a MIDI representation of a sound includes values for the note's pitch, length, and volume. It can also include additional characteristics, such as attack and delay time.

MIME
Multipurpose Internet Mail Extensions, a specification for formatting non-ASCII messages so that they can be sent over the Internet. Many e-mail clients now support MIME, which enables them to send and receive graphics, audio, and video files via the Internet mail system. In addition, MIME supports messages in character sets other than ASCII. MIME was defined in 1992 by the Internet Engineering Task Force (IETF).

MLM
(1) Mailing List Manager.

(2) Multi Level Marketing.

MLPPP
MultiLink PPP, an extension of the PPP that allows the B-channels of ISDN lines to be used in combination as a single transmission line, doubling throughput to 128 Kbps.

MMS
Multimedia Messaging Service is, as its name suggests, the ability to send messages comprising a combination of text, sounds, images and video to MMS capable handsets (mobile phones).

MMU
Memory Management Unit. The hardware component that manages virtual memory systems. Typically, the MMU is part of the CPU, though in some designs it is a separate chip. The MMU includes a small amount of memory that holds a table matching virtual addresses to physical addresses. This table is called the Translation Look-aside Buffer (TLB). All requests for data are sent to the MMU, which determines whether the data is in RAM or needs to be fetched from the mass storage device. If the data is not in memory, the MMU issues a page fault interrupt.

MNP
Microcom Networking Protocol, a communications protocol, that is used by many high-speed modems.

Mobo
Abbreviation for motherboard.

Module
(1) In software, a module is a part of a program. Programs are composed of one or more independently developed modules that are not combined until the program is linked. A single module can contain one or several routines.
(2) In hardware, a module is a self-contained component.

Mosaic
The first GUI web browser programme with the same interface for Macintosh, Windows and Unix.

Mount
(1) To make a mass storage device available.

(2) To install a device, such as a disk drive or expansion board.

Mouse Potato
The computer equivalent of a couch potato.

Mozilla
The original name for Netscape Navigator.

MPEG
Motion Picture Expert Group - a file format for encoding and compressing video and sound data. Well suited to transferring short films or movies over the internet.

MP3
An audio component of the MPEG file format which allows high-quality music playback from a significantly smaller file than otherwise possible.

MPLS
MultiProtocol Label Switching. An IETF initiative that integrates Layer 2 information about network links into Layer 3 within a particular autonomous system in order to simplify and improve IP-packet exchange. MPLS gives network operators a great deal of flexibility to divert and route traffic around link failures, congestion, and bottlenecks. From a QoS standpoint, ISPs will better be able to manage different kinds of data streams based on priority and service plan. For instance, those who subscribe to a premium service plan, or those who receive a lot of streaming media or high-bandwidth content can see minimal latency and packet loss.

MPOA
Multiprotocol Over ATM, is a specification that enables ATM services to be integrated with existing LANs that use Ethernet, Token-Ring or TCP/IP protocols. The goal is to allow different LANs to send packets to each other via an ATM backbone.  MPOA operates at level 3 of the OSI Reference Model.

MPP
Massively Parallel Processors.

MSCDEX
Microsoft CD-ROM Extension, a driver that enables DOS and Windows 3.x systems to recognise and control CD-ROM players. The driver is located in a file called MSCDEX.EXE. Windows 95 replaces MSCDEX with a 32-bit, dynamically loadable driver called CDFS.

MSP
Management Service Provider. A company that looks after another company's information technology services.

MTA
Message Transfer Agent, the program responsible for receiving incoming e-mails and delivering the messages to individual users. The MTA transfers messages between computers. Hidden from the average user, it is responsible for routing messages to their proper destinations. MTAs receive messages from both MUAs and other MTAs, although single-user machines more often retrieve mail messages using POP.

MUA
Mail User Agent, the software that allows a user to access and manage e-mail, including reading, composing, disposing, printing and displaying e-mail messages. The MUA provides the interface between the user and the MTA.

MUD
Multiple User Dungeon - a glorified chat room based on the idea of role-playing games where gamers interact and compete in exploring a virtual map and solving puzzles.

Multi-Media
A combination of any of the following: text, sound, still or animated graphics and video images. The term is typically used in reference to electronic media, such as the Internet and CD-Roms.

Multicasting
To transmit a single message to a select group of recipients. A simple example of multicasting is sending an e-mail message to a mailing list. Teleconferencing and videoconferencing also use multicasting, but require more robust protocols and networks. Standards are being developed to support multicasting over a TCP/IP network such as the Internet. These standards, IP Multicast and Mbone, will allow users to easily join multicast groups.

MVS
Multiple Virtual Storage , the operating system for older IBM mainframes.

Nano Technology
Nano Technology refers to very small machines, so small that they are constructed by arranging individual atoms in carefully designed patterns. This is a rapidly developing technology which promises to be very valuable in the 21st century for such fields as medical surgury and construction of computers and robots.

NAP
Network Access Point, is a public network exchange facility where ISPs can connect with one another in peering arrangements.  It is a key component of the Internet backbone.

NAS
Network-Attached Storage, is a server that is dedicated to nothing more than file sharing. NAS does not provide any of the activities that a server in a server-centric system typically provides, such as e-mail, authentication or file management. NAS allows more hard disk storage space to be added to a network that already utilises servers without shutting them down for maintenance and upgrades. With a NAS device, storage is not an integral part of the server. Instead, in this storage-centric design, the server still handles all of the processing of data but a NAS device delivers the data to the user.

NAT
Network Address Translation, an Internet standard that enables a LAN to use one set of IP addresses for internal traffic and a second set of addresses for external traffic. A NAT box located where the LAN meets the Internet makes all necessary IP address translations.

NCSC
National Computing Security Center. A US government organisation within the NSA that developed the TCSEC and TNIEG.

NDIS
Network Driver Interface Specification. Specification that defines a standard interface for communicatiation between the media access control sublayer and protocol drivers.

NDS
Novell Directory Services.

NetBEUI
NetBIOS Extended User Interface. An improved version of the NetBIOS protocol used in a number of network operating systems.

NetBIOS
Network Basic Input/Output System. A session layer protocol used for application communication on LANs. It is an API that can be used by applications to request network services.

Netiquette
The code of conduct or etiquette governing behaviour on the Net. Examples of bad netiquette include supplying incorrect or out-of-date e-mail addresses, and posting a message to dozens of newsgroups (spamming), and writing emails in capitals.

Network
Name for any two or more computers are connected together by cables or other means and using software to enable them to share devices and information.

Network Meltdown
A state in which a network grinds to a halt due to excessive traffic. A network meltdown generally starts as a broadcast storm that gets out of control, but even legitimate network messages can cause a meltdown if the network hasn't been designed to accommodate that level of traffic.

Newbie
Someone who is new to the Internet.

Newsgroup
Groups of people getting together on the Internet to discuss a particular subject.

Newsreader
A program that allows users to read Usenet newsgroups. Some Web browsers have the ability to read and post articles in addition to browsing the Web.

NFS
Network File System, an open operating system designed by Sun Microsystems that allows all network users to access shared files stored on computers of different types. NFS provides access to shared files through an interface called the Virtual File System (VFS) that runs on top of TCP/IP. Users can manipulate shared files as if they were stored locally on the user's own hard disk.

NHRP
Next Hop Resolution Protocol, is a protocol or method that can be used so that a computer sending data to another computer can learn the most direct route to the receiving computer.

NHTCU
National Hi-Tech Crime Unit.

Nibble
4 bits.

NIC
Network Interface Card. An expansion board you insert into a computer so the computer can be connected to a network.

NIST
National Institute of Standards and Technology.

Nit
A unit of measurement of luminance, or the intensity of visible light, where one nit is equal to one candela per square meter. Nits are used to describe the brightness of computer displays, such as LCD and CRT monitor.

NLP
Natural Language Processing. A branch of artificial intelligence that deals with analysing, understanding and generating the languages that humans use naturally in order to interface with computers in both written and spoken contexts using natural human languages instead of computer languages. NLP is also referred to as computational linguistics.

NNTP
Network News Transfer Protocol. The protocol used to post, distribute, and retrieve USENET messages.

Node
(1) In networks, a processing location. A node can be a computer or some other device, such as a printer. Every node has a unique network address, sometimes called a Data Link Control (DLC) address or Media Access Control (MAC) address.
(2) In tree structures, a point where two or more lines meet.

Northbridge
Northbridge is an Intel chipset that communicates with the computer processor and controls interaction with memory, the PCI bus, Level 2 cache, and all AGP activities. Northbridge communicates with the processor using the FSB. Northbridge is one part of a two-part chipset called Northbridge/Southbridge.
See Southbridge.

NOW
Network of Workstations.

NSA
Nation Security Agency, is the official U.S. cryptologic organisation.

NSAPI
Netscape Server Application Program Interface, an API for Netscape's Web servers. NSAPI enables programmers to create Web-based applications that are more sophisticated and run much faster than applications based on CGI scripts.

Nslookup
A program that allows a user to find out the internet address for an entered hostname, or vice versa.

NTFS
NT File System. It is one of the file systems for the Windows NT operating system (Windows NT also supports the FAT file system). NTFS has features to improve reliability, such as transaction logs to help recover from disk failures. To control access to files, you can set permissions for directories and/or individual files. NTFS files are not accessible from other operating systems such as DOS. For large applications, NTFS supports spanning volumes, which means files and directories can be spread out across several physical disks.

NUMA
Non-Uniform Memory Access, a type of parallel processing architecture in which each processor has its own local memory but can also access memory owned by other processors. It's called non-uniform because the memory access times are faster when a processor accesses its own memory than when it borrows memory from another processor. NUMA computers offer the scalability of MPP and the programming ease of SMP.

NVRAM
Non-Volatile Random Access Memory, a type of memory that retains its contents when power is turned off.

NYM
A shortened form of the word pseudonym, a nym is an anonymous invented name that a person can use in e-mail or in online discussions arenas, such as chat rooms or newsgroups. Some people create nyms because they want to protect their privacy on the Internet, while others create nyms to keep from being identified because they are involved in unethical practices, such as spam.

NYM Server
A computer that allows a subscribing user to send and receive e-mail messages using a nym, or assumed name, without revealing the user's true identity.

OBI
Open Buying on the Internet, is a standard that creates a flexible framework for B2B solutions. Its goal is to automate a high-volume, low-price transaction between trading partners.

OCR
Optical Character Recognition. Electronic recognition of printed or written text characters. Resulting that a scanned document doesn't need to be retyped.

OCX
An Object Linking and Embedding (OLE) custom control.  It provides functions such as window resizing. Microsoft now calls it an ActiveX Control.

ODBC
Open DataBase Connectivity, a standard database access method. The goal of ODBC is to make it possible to access any data from any application, regardless of which database management system (DBMS) is handling the data.

ODI
Open Data-Link Interface, a driver specification that enables different protocols, working at the data-link layer of the OSI model to share the same NIC and NIC driver.

OEM
Original Equipment Manufacturer.

OFDM
Orthogonal Frequency Division Multiplexing, an FDM modulation technique for transmitting large amounts of digital data over a radio wave. OFDM works by splitting the radio signal into multiple smaller sub-signals that are then transmitted simultaneously at different frequencies to the receiver. OFDM reduces the amount of crosstalk in signal transmissions. 802.11a WLAN technology uses OFDM.
Compare with FHSS and DSSS.

OFX
Open Financial Exchange, a unified specification for the exchange of electronic financial data over the Internet. Using a request-response system of communication, OFX allows a client to connect directly to a financial institution's server.
See FIX.

OLAP
Online Analytical Processing, a category of software tools that provides analysis of data stored in a database. OLAP tools enable users to analyze different dimensions of multidimensional data. For example, it provides time series and trend analysis views.
The chief component of OLAP is the OLAP server, which sits between a client and a database management systems (DBMS). The OLAP server understands how data is organized in the database and has special functions for analyzing the data. There are OLAP servers available for nearly all the major database systems.

OLE
Object Linking and Embedding. OLE is a compound document standard developed by Microsoft Corporation. It enables you to create objects with one application and then link or embed them in a second application. Embedded objects retain their original format and links to the application that created them. Support for OLE is built into the Windows and Macintosh operating systems. A competing compound document standard developed jointly by IBM, Apple Computer, and other computer firms is called OpenDoc.

OLED
Organic light-emitting diode, a display device that sandwiches carbon-based films between two charged electrodes, resulting in light when voltage is applied.

OMG
Object Management Group, is an organisation that has goals to provide a common framework for developing applications using object-oriented programming techniques.  OMG is responsible for the CORBA specification.

On The Fly
Expression meaning 'in real time' - commonly used when a web page is constructed automatically at the time of retrieval by the user, for example by compiling the results of a search engine.

OOG
Object Oriented Graphics. The representation of graphical objects, such as lines, arcs, circles, and rectangles, with mathematical formulas. This method of describing objects enables the system to manipulate the objects more freely. In an object-oriented system, for example, you can overlap objects but still access> them individually, which is difficult in a bit-mapped system. One of the most widely used formats for object-oriented graphics is PostScript. PostScript is a PDL that makes it possible to describe objects and manipulate them in various ways.

OOP
Object-Oriented Programming. A type of programming in which programmers define not only the data type of a data structure, but also the types of operations (functions) that can be applied to the data structure. In this way, the data structure becomes an object that includes both data and functions. In addition, programmers can create relationships between one object and another.

OpenDoc
A standard and application programming interface (API) that makes it possible to design independent programs (components) that can work together on a single document. OpenDoc is being developed by a loose alliance of companies, including Apple Computer, IBM, and Lotus. Notably absent from this list is Microsoft, which is pushing an alternative standard and API called Object Linking and Embedding (OLE).

Opera
A Web browser.

ORB
Object Request Broker, a compenent in the CORBA programming model that acts as a middleware between clients and servers.

ORM
(1) Object Role Modeling. A conceptual database design methodology that allows the user to express information as an object and explore how it relates to other information objects.

(2) Operational Risk Management. It is an emerging area in risk management. The goal is to control and to mitigate operational risks when there is economic reason to do so.

OSI
Open System Interconnection, an ISO standard for worldwide communications that defines a networking framework for implementing protocol in seven layers. Control is passed from one layer to the next, starting at the application layer in one station, proceeding to the bottom layer, over the channel to the next station and back up the hierarchy. Seven layers are as follows:

7. Application
6. Presentation
5. Session
4. Transport
3. Network
2. Data Link
1. Physical

OSP
Online Service Provider, is an ISP that have their own independant online content, eg AOL, compared to an ISP that simply connect users directly to the Internet.

OSPF
Open Shortest Path First, is a routing propcol developed for IP networks based on the shortest path first or link-state algorithm.  See RFC 1583.

OTP
Open Trading Protocol, is a framework developed by the IETF to provide interoperability for Internet commerce between a buyer and a merchant with no prior relationship.

OUI
Organisationally Unique Identifier. Code assigned by the IEEE to an organisation that makes NICs. This and the manufacturer's unique card code becomes the MAC Address.

Overflow Error
An error that occurs when the computer attempts to handle a number that is too large for it. Every computer has a well-defined range of values that it can represent. If during execution of a program it arrives at a number outside this range, it will experience an overflow error. Overflow errors are sometimes referred to as overflow conditions.

P2P
Peer-to-Peer.

Packet
Any information sent over a network is divided into chucks of data called packets, which are then routed. Additional bits are added to the information, such as address of the sender and receiver, error control information and check procedures, to ensure that the right information gets to where it has been requested to goto in the correct form.

PAN
Personal Area Network is an IBM technology that allows individuals to exchange data via a receiver and transmitter. It is based on the electric-field transmission medium.

PAP
Password Authentication Protocol. In PPP networks, a method of validating connection requests.

PAT
Port Address Translation, a type of network address translation (NAT). During PAT, each computer on LAN is translated to the same ip address, but with a different port number assignment. PAT is also referred to as overloading, port mapping, port-level multiplexed NAT or single address NAT.

Patch
A software upgrade that corrects a programming problem. Also known as a Fix.

PCI
Peripheral Component Interconnect, a local bus standard developed by Intel. Most modern PCs include a PCI bus in addition to a more general ISA expansion bus. Many analysts, however, believe that PCI will eventually supplant ISA entirely. PCI is also used on newer versions of the Macintosh computer.
PCI is a 64-bit bus, though it is usually implemented as a 32-bit bus. It can run at clock speeds of 33 or 66 MHz. At 32 bits and 33 MHz, it yields a throughput rate of 133 MBps.

PCL
Printer Control Language, the page description language ( PDL) developed by Hewlett Packard and used in many of their laser printer and ink-jet printers. PCL 5 and later versions support a scalable font technology called Intellifont.

PCMCIA
Personal Computer Memory Card International Association, is an organization consisting of some 500 companies that has developed a standard for small, credit card-sized devices, called PC Cards. Originally designed for adding memory to portable computers, the PCMCIA standard has been expanded several times and is now suitable for many types of devices. There are now three types of PCMCIA cards.
In general, you can exchange PC Cards on the fly, without rebooting your computer.

PCS
Personal Communications Service, describes a set of digital mobile phone technologies being deployed in the U.S. PCS is a second generation mobile communications technology.

PDA
Personal Digital Assistant, a handheld device that combines computing, telephone/fax, and networking features. Most PDAs are pen-based, rather than keyboard based for input.

PDL
Page Description Language. A language for describing the layout and contents of a printed page. The best-known PDLs are Adobe PostScript and Hewlett-Packard PCL (Printer Control Language), both of which are used to control laser printers.

PERL
Practical Extraction and Report Language, Perl is a programming language especially designed for processing text. Because of its strong text processing abilities, Perl has become one of the most popular languages for writing CGI scripts. Perl is an interpretive language, which makes it easy to build and test simple programs.

PGA
(1) Pin Grid Array, a type of chip package in which the connecting pins are located on the bottom in concentric squares. PGA chips are particularly good for chips that have many pins, such as modern microprocessors.

(2) Professional Graphics Adapter, a video standard developed by IBM that supports 640x480 resolution

PGP
Pretty Good Privacy. A technique for encrypting messages. PGP is one of the most common ways to protect messages on the Internet because it is effective, easy to use, and free. PGP is based on the public-key method, which uses two keys -- one is a public key that you disseminate to anyone from whom you want to receive a message. The other is a private key that you use to decrypt messages that you receive. To encrypt a message using PGP, you need the PGP encryption package, which is available for free from a number of sources.

Phishing
A scam where the perpetrator sends out legitimate-looking e-mails appearing to come from some of the Web's biggest sites in an effort to phish for personal and financial information from the recipient. Phishers use any number of different social engineering and e-mail spoofing ploys to try to trick their victims.

PHP
(1) Personal Home Page.

(2) PHP Hypertext Preprocessor is a server-side, HTML embedded scripting language used to create dynamic Web pages. In an HTML document, PHP script (similar syntax to that of Perl or C ) is enclosed within special PHP tags. Because PHP is embedded within tags, the author can jump between HTML and PHP instead of having to rely on heavy amounts of code to output HTML. And, because PHP is executed on the server, the client cannot view the PHP code. PHP can perform any task any CGI program can do, but its strength lies in its compatibility with many types of databases. Also, PHP can talk across networks using IMAP, SNMP, NNTP, POP3, or HTTP.

Phreaking
Closely related to hacking, using a computer or other device to trick a phone system. Typically, phreaking is used to make free calls or to have calls charged to a different account.

PLED
Polymer, or polymeric, light-emitting diode, a backlighting, illumination and display technology.

Plug and Play
Refers to the ability of a computer system to automatically configure expansion boards and other devices. You should be able to plug in a device and play with it, without worrying about setting DIP switches, jumpers, and other configuration elements. Since the introduction of the NuBus, the Apple Macintosh has been a plug-and-play computer. The Plug and Play (PnP) specification has made PCs more plug-and-play, although it doesn't always work as advertised. see face="Times New Roman" size="-1" color="#0000FF">Plug and Pray

Plug and Pray
Slang for Plug and Play, due to the problems of the devices automatically configuring themselves to conflict with other devices and to change configuration each time the PC was rebooted.

Plug-in
A hardware or software module that adds a specific feature or service to a larger system. For example, there are number of plug-ins for the Netscape Navigator browser that enable it to display different types of audio or video messages. Navigator plug-ins are based on MIME file types.

Polyline
In computer graphics, a continuous line composed of one or more line segments. You can create a polyline by specifying the endpoints of each segment. In draw programs, you can treat a polyline as a single object, or divide it into its component segments.

PON
Passive Optical Network, is a high bandwidth point to multipoint optical fiber network based on the ATM protocol. PONs are capable of delivering high volumes of bandwidth, which can be changed on-the-fly depending on an individual user's needs.

POP
(1) Short for Post Office Protocol, a protocol used to retrieve e-mail from a mail server. Most e-mail applications (sometimes called an e-mail client ) use the POP protocol, although some can use the newer IMAP.

(2) Point Of Presence, a telephone number that gives you dial-up access. Internet Service Providers (ISPs) generally provide many POPs so that users can make a local call to gain Internet access.

Port
(n) (1) An interface on a computer to which you can connect a device. Personal computers have various types of ports. Internally, there are several ports for connecting disk drives, display screens, and keyboards. Externally, personal computers have ports for connecting modems , printers, mice, and other peripheral devices.

(2) In TCP/IP and UDP networks, an endpoint to a logical connection. The port number identifies what type of port it is. For example, port 80 is used for HTTP traffic.

(v) To move a program from one type of computer to another. To port an application, you need to rewrite sections that are machine dependent, and then recompile the program on the new computer. Programs that can be ported easily are said to be portable.

Portal
A web site that greets users, gives large amount of information on a specific topic and offers links to other related web sites.

POSIX
Portable Operating System Interface for UNIX, a set of IEEE and ISO standards that define an interface between programs and operating systems. By designing their programs to conform to POSIX, developers have some assurance that their software can be easily ported to POSIX compliant operating systems. This includes most varieties of UNIX as well as NT.
The POSIX standards are now maintained by an arm of the IEEE called the Portable Applications Standards Committee (PASC).

POST
(1) (v) To publish a message in an online forum or newsgroup or e-Mail.
(n) A message published in an online forum or newsgroup or e-Mail.

(2) Power-On Self Test. When power is turned on, POST is the diagnostic testing sequence that a computer's basic input/output system (or "starting program") runs to determine if the computer keyboard, random access memory, disk drives, and other hardware are working correctly.

Postscript
A page description language (PDL) developed by Adobe Systems in 1985. PostScript is primarily a language for printing documents on laser printers , but it can be adapted to produce images on other types of device. PostScript is the standard for desktop publishing because it is supported by imagesetters, the very high-resolution printer used by service bureaus. PostScript is an object-oriented language, meaning that it treats images, including fonts, as collections of geometrical object rather than as bit maps.

POTS
Plain Old Telephone Service, which refers to the standard telephone service that most homes use. It is generally restricted to about 52Kbps.
The POTS network is also called the public switched telephone network ( PSTN).

PPGA
Plastic Pin Grid Array. PPGAs were first developed by Intel in 1993 to combat power supply decoupling issues in high-performance microprocessors.This square chip packaging technology was designed for microprocessors with greater numbers of transistors on each chip than previous models.

PPI
Pixels per Inch, is a measure of the sharpness (that is, the density of illuminated points) on a display screen. The dot pitch determines the absolute limit of the possible pixels per inch. However, the displayed resolution of pixels (picture elements) that is set up for the display is usually not as fine as the dot pitch. The pixels per inch for a given picture resolution will differ based on the overall screen size since the same number of pixels are being spread out over a different space. The term "dots per inch" (DPI), extended from the print medium, is sometimes used instead of pixels per inch.

PPP
Point-to-Point Protocol, a method of connecting a computer to the Internet. PPP is more stable than the older SLIP protocol and provides error checking features.

PPPoE
Point-to-Point Protocol over Ethernet. PPPoE relies on two widely accepted standards: PPP and Ethernet. PPPoE is a specification for connecting the users on an Ethernet to the Internet through a common broadband medium, such as a single DSL line, wireless device or cable modem.

PPTP
Point-to-Point Tunneling Protocol, a new technology for creating Virtual Private Networks (VPNs). Because the Internet is essentially an open network, the Point-to-Point Tunneling Protocol (PPTP) is used to ensure that messages transmitted from one VPN node to another are secure. With PPTP, users can dial in to their corporate network via the Internet.

PRI
Primary-Rate Interface, a type of ISDN service designed for larger organisations. PRI includes 23 B-channels (30 in Europe) and 1 D-Channel. PRI service is generally transmitted through a T-1 line (or an E1 line in Europe).
See BRI.

Protocol
An agreed-upon format for transmitting data between two devices. The protocol determines the following:

a) the type of error checking to be used
b) data compression method, if any
c) how the sending device will indicate that it has finished sending a message
d) how the receiving device will indicate that it has received a message

There are a variety of standard protocols from which programmer can choose. Each has particular advantages and disadvantages; for example, some are simpler than others, some are more reliable, and some are faster. From a user's point of view, the only interesting aspect about protocols is that your computer or device must support the right ones if you want to communicate with other computers. The protocol can be implemented either in hardware or in software.

PSTN
Public Switched Telephone Network, which refers to the international telephone system based on copper wires carrying analog voice data.

Pull
To request data from another program or computer.

Pulsing Zombie
A form of DoS attack known as a degradation-of-service attack, as opposed to a denial-of-service attack. Unlike a regular zombie that paralyzes a system by inundating it with a steady stream of attack traffic, the pulsing zombie attacks with irregular small bursts of attack traffic from multiple sources on a single target over an extended period of time. Pulsing zombie attacks are more difficult to detect and trace because since they are slow and gradual they do not immediately appear as malicious.

Pure Play
A dot-com that has no presence on the high street.

Push
(1) In client/server applications, to send data to a client without the client requesting it.
(2) In programming, to place a data item onto a stack.

Python
An interpreted, object-oriented programming language. Python is very portable since Python interpreters are available for most operating system platforms. Although Python is copyrighted, the source code is freely available, and unlike GNU software, it can be commercially re-sold.

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