PDA ~ pipeline processing
A/B Switch box ~ America On-line AMI BIOS ~ Arithmetic Operation ARP ~ AVI Backbone ~ Bit Image Bit Map ~ Boot Disk Boot Drive ~ Bytes Per Inch C++ ~ Carrier Frequency carrier system ~ certification CGI ~ Chooser extension cipher ~ Clipper Chip clock ~ color color bits ~ communications satellite communications server ~ computer security CON ~ copy copy program ~ cycle time daemon ~ defragmentation demand paging ~ digitize DikuMUD ~ disk disk buffer ~ Document Style Semantics and Specification Language document window ~ dynamic Web page Easter egg ~ erase erase head ~ ezine F2F ~ finger2 firewall ~ font suitcase footer ~ FYI Game Control Adapter ~ GUI HAL ~ hot key1 hot key2 ~ Hz i486DX ~ internal modem internet ~ ISO 9660 ISO/OSI model ~ just-in-time K1 ~ knowledge base L1 cache ~ LU luggable computer ~ LZW compression MAC ~ MILNET mime ~ msec MTBF ~ MYOB named anchor ~ network drive Network File System ~ number crunching object ~ overwrite mode P5 ~ PC/XT keyboard PDA ~ pipeline processing piracy ~ preventive maintenance preview ~ pwd quasi-language ~ QWERTY keyboard R&D ~ registration marks Registry ~ RFI RF shielding ~ run-time library SAA ~ server error server push-pull ~ soft return software ~ style sheet stylus ~ System T1 ~ ToggleKeys token ~ typography UART ~ uupc V.120 ~ view2 viewer ~ VxD w3 ~ WinG WINS ~ WWW X.25 ~ X Windows Yahoo! ~ yotta- Z39.50 standard ~ Zulu time
PDA
n. Acronym for Personal Digital Assistant. A lightweight palmtop computer designed to provide specific functions like personal organization (calendar, note taking, database, calculator, and so on) as well as communications. More advanced models also offer multimedia features. Many PDA devices rely on a pen or other pointing device for input instead of a keyboard or mouse, although some offer a keyboard too small for touch typing to use in conjunction with a pen or pointing device. For data storage, a PDA relies on flash memory instead of power-hungry disk drives. See also firmware, flash memory, PC Card, pen computer.
PDC
n. See Primary Domain Controller.
PDL
n. See page-description language.
PDM
n. See pulse duration modulation.
PDO
n. See Portable Distributed Objects.
peer
n. Any of the devices on a layered communications network that operate on the same protocol level. See also network architecture.
peer-to-peer architecture
n. A network of two or more computers that use the same program or type of program to communicate and share data. Each computer, or peer, is considered equal in terms of responsibilities and each acts as a server to the others in the network. Unlike a client/server architecture, a dedicated file server is not required. However, network performance is generally not as good as under client/server, especially under heavy loads. Also called peer-to-peer network. See also peer, peer-to-peer communications, server. Compare client/server architecture.
peer-to-peer communications
n. Interaction between devices that operate on the same communications level on a network based on a layered architecture. See also network architecture.
pel
n. Short for picture element. See pixel.
Pentium
n. A microprocessor introduced by Intel Corporation in March 1993 as the successor to the i486. The Pentium is a superscalar, CISC-based microprocessor containing 3.3 million transistors. The Pentium has a 32-bit address bus, a 64-bit data bus, a built-in floating-point unit and memory management unit, two built-in 8-KB L1 caches, and a System Management Mode (SMM), which provides the microprocessor with the ability to slow or halt some system components when the system is idle or performing non-CPU-intensive tasks, thereby lessening power consumption. The Pentium also employs branch prediction, resulting in faster system performance. In addition, the Pentium has some built-in features to ensure data integrity, and it supports functional redundancy checking (FRC). See also branch prediction, CISC, functional redundancy checking, i486DX, L1 cache, microprocessor, P5, superscalar. Compare Pentium Pro (definition 1).
Pentium Pro
n. 1. Intel's 150-200 MHz family of 32-bit processors, released in November 1995. The Pentium Pro is considered the next generation of processors in the 8086 family, following the Pentium, and is designed for running 32-bit operating systems and applications. See also 32-bit application, 32-bit operating system, 8086, microprocessor, Pentium. 2. A PC that has a Pentium Pro processor.
Pentium upgradable
n. 1. An i486 motherboard capable of being adapted to run a Pentium-class processor. See also i486DX, microprocessor, motherboard, Pentium. 2. A 486 PC that can be upgraded to Pentium class by adding a Pentium processor. See also i486DX.
performance monitor
n. A process or program that appraises and records status information about various system devices and other processes.
period
n. The length of time required for an oscillation to complete one full cycle. For an oscillation electrical signal, the period is the time between waveform repetitions. If f is the frequency of oscillation in hertz, and t is the period in seconds, then t = 1/f.
peripheral
n. In computing, a device, such as a disk drive, printer, modem, or joystick, that is connected to a computer and is controlled by the computer's microprocessor. Also called peripheral device. See also console.
peripheral power supply
n. An auxiliary source of electricity used by a computer or a device as a backup in case of a power failure. Acronym: PPS.
Perl
n. Acronym for Practical Extraction and Report Language. An interpreted language, based on C and several UNIX utilities. Perl has powerful string-handling features for extracting information from text files. Perl can assemble a string and send it to the shell as a command; hence, it is often used for system administration tasks. A program in Perl is known as a script. Perl was devised by Larry Wall at NASA's Jet Propulsion Laboratory.
permanent storage
n. A recording medium that retains the data recorded on it for long periods of time without power. Ink on paper is by far the most widely used permanent storage, but data can be transferred from paper to a computer only with difficulty. Typically, some form of magnetic medium, such as floppy disk or tape, is preferable. Magnetic media are generally accepted as permanent, even though the magnetic fields that encode data in the media tend to fade eventually (in five years or more). See also nonvolatile memory.
permanent swap file
n. In Windows, a file composed of contiguous disk sectors used for virtual memory operations. See also swap file, virtual memory.
permission
n. In a networked or multiuser computer environment, the ability of a particular user to access a particular resource by means of his or her user account. Permissions are granted by the system administrator or other authorized person; these permissions are stored in the system (often in a file called a permissions log) and are checked when a user attempts to access a resource.
persistent link
n. See hot link (definition 1).
personal computer
n. A computer designed for use by one person at a time. Personal computers do not need to share the processing, disk, and printer resources of another computer. IBM PC-compatible computers and Apple Macintoshes are both examples of personal computers. Acronym: PC.
peta-
prefix. Abbreviated P. Denotes 1 quadrillion (1015). In computing, which is based on the binary (base-2) numbering system, peta- has a literal value of 1,125,899,906,842,624, which is the power of 2 (250) closest to 1 quadrillion.
petabyte
n. Abbreviated PB. Either 1 quadrillion bytes or 1,125,899,906,842,624 bytes.
PGP
n. Acronym for Pretty Good Privacy. A program for public key encryption, using the RSA algorithm, developed by Philip Zimmermann. PGP software is available in unsupported free versions and supported commercial versions from Pretty Good Privacy, Inc., Redwood Shores, Calif. See also privacy, public key encryption, RSA encryption.
phase modulation
n. A method of imposing information onto a waveform signal by shifting the phase of the wave to represent information, such as the binary digits 0 and 1. See also phase-shift keying.
Phoenix BIOS
n. An IBM-compatible ROM BIOS manufactured by Phoenix Technologies, Ltd. A popular ROM BIOS in many so-called PC "clone" computers, the Phoenix BIOS was an early leader in IBM-compatible computers shortly after they began to appear in the marketplace. See also BIOS, ROM BIOS. Compare AMI BIOS.
phone connector
n. An attachment, usually an RJ-11 connector, used to join a telephone line to a device such as a modem.
PhotoCD
n. A digitizing system from Kodak that allows 35mm film pictures, negatives, slides, and scanned images to be stored on a compact disc. Images are stored in a file format called Kodak PhotoCD IMAGE PAC File Format, or PCD. Many photography or film development businesses offer this service. Images stored on a PhotoCD can usually be viewed by any computer with CD-ROM capabilities and the software required to read PCD. Such images can also be viewed using one of a variety of players designed to display images stored on CDs.
photo editor
n. A graphics application used to manipulate an image, such as a scanned photograph, digitally.
photorealism
n. The process of creating images that are as close to photographic or "real-life" quality as possible. In computer graphics, photorealism requires powerful computers and highly sophisticated software and is heavily mathematical. See also ray tracing.
phototypesetter
n. A printer similar to a laser printer but capable of resolutions over 2000 dots per inch. Phototypesetters apply light directly to a photographic film or photosensitive paper. See also photocomposition. Compare imagesetter.
physical
adj. In computing, of, pertaining to, or characteristic of a real, as opposed to a conceptual, piece of equipment or frame of reference. Compare logical (definition 2).
physical address
n. An address that corresponds to a hardware memory location. In simple processors such as the 8088 and the 68000, every address is a physical address. In processors supporting virtual memory, programs reference virtual addresses, which are then mapped by memory management hardware onto physical addresses. See also memory management unit, paging, virtual memory.
physical layer
n. The first, or lowest, of the seven layers in the International Organization for Standardization's Open Systems Interconnection (OSI) model for standardizing computer-to-computer communications. The physical layer is totally hardware-oriented and deals with all aspects of establishing and maintaining a physical link between communicating computers. Among specifications covered on the physical layer are cabling, electrical signals, and mechanical connections. See also ISO/OSI model.
physical memory
n. Memory actually present in the system, as opposed to virtual memory. A computer might have only 4 megabytes of physical RAM but support a virtual memory capacity of 20 MB. Compare virtual memory.
PIC
n. See programmable interrupt controller.
pica
n. 1. With reference to typewriters, a fixed-width type font that fits 10 characters to the linear inch. See also pitch (definition 1). 2. As used by typographers, a unit of measure equal to 12 points or approximately 1/6 inch. See also point1 (definition 1).
pico-
prefix. Abbreviated p. Denotes one trillionth (10-12), or, in the British numbering system, one million millionth.
picoJava
n. A microprocessor developed by Sun Microsystems, Inc., that executes Java code. See also Java.
picosecond
n. Abbreviated psec. One trillionth of a second.
PICS
n. Acronym for Platform for Internet Content Selection. A standard for enabling users to filter their Web access automatically using software (such as Internet Explorer 3.0) that detects codes for ratings in the sites' HTML files. In addition to filtering out undesirable material, PICS can be used to screen sites according to whether they contain material of interest. Several rating systems, emphasizing different sets of criteria, are in use.
PICT
n. A file-format standard for encoding graphical images, both object-oriented and bitmapped. The PICT file format was first used in Apple Macintosh applications, but many IBM PC-compatible applications can read the format too. See also bitmapped graphics, object-oriented graphics.
pie chart
n. A type of graph that presents values as percentages (slices) of a whole (a pie).
PIM
n. Acronym for personal information manager. An application that usually includes an address book and organizes unrelated information, such as notes, appointments, and names, in a useful way.
pin
n. A slender prong. Pins are commonly encountered as the contacts protruding from a male connector. Connectors are often identified by the number of pins they have. Other types of pins are the spidery, leglike metal appendages that connect computer chips to sockets on a circuit board or directly to the circuit board.
PIN
n. Acronym for personal identification number. A unique code number assigned, as with automatic teller machine cards, to the authorized user.
ping1
n. 1. Acronym for Packet Internet Groper. A protocol for testing whether a particular computer is connected to the Internet by sending a packet to its IP address and waiting for a response. The name actually comes from submarine active sonar, where a sound signal--called a "ping"--is broadcast, and surrounding objects are revealed by their reflections of the sound. 2. A UNIX utility that implements the ping protocol.
ping2
vb. 1. To test whether a computer is connected to the Internet using the ping utility. 2. To test which users on a mailing list are current by sending e-mail to the list asking for a response.
Ping of Death
n. A form of Internet vandalism that entails sending a packet that is substantially larger than the usual 64 bytes over the Internet via the ping protocol to a remote computer. The size of the packet causes the computer to crash or reboot. See also packet (definition 2), ping1 (definition 1).
pinout
n. A description or diagram of the pins of a chip or connector. See also pin.
pipe
n. 1. A portion of memory that can be used by one process to pass information along to another. Essentially, a pipe works like its namesake: it connects two processes so that the output of one can be used as the input to the other. See also input stream, output stream. 2. The vertical line character (|) that appears on a PC keyboard as the shift character on the backslash (\) key. 3. In UNIX, a command function that transfers the output of one command to the input of a second command.
pipeline processing
n. A method of processing on a computer that allows fast parallel processing of data. This is accomplished by overlapping operations using a pipe, or a portion of memory that passes information from one process to another. See also parallel processing, pipe (definition 1), pipelining (definition 3).
A/B Switch box ~ America On-line AMI BIOS ~ Arithmetic Operation ARP ~ AVI Backbone ~ Bit Image Bit Map ~ Boot Disk Boot Drive ~ Bytes Per Inch C++ ~ Carrier Frequency carrier system ~ certification CGI ~ Chooser extension cipher ~ Clipper Chip clock ~ color color bits ~ communications satellite communications server ~ computer security CON ~ copy copy program ~ cycle time daemon ~ defragmentation demand paging ~ digitize DikuMUD ~ disk disk buffer ~ Document Style Semantics and Specification Language document window ~ dynamic Web page Easter egg ~ erase erase head ~ ezine F2F ~ finger2 firewall ~ font suitcase footer ~ FYI Game Control Adapter ~ GUI HAL ~ hot key1 hot key2 ~ Hz i486DX ~ internal modem internet ~ ISO 9660 ISO/OSI model ~ just-in-time K1 ~ knowledge base L1 cache ~ LU luggable computer ~ LZW compression MAC ~ MILNET mime ~ msec MTBF ~ MYOB named anchor ~ network drive Network File System ~ number crunching object ~ overwrite mode P5 ~ PC/XT keyboard PDA ~ pipeline processing piracy ~ preventive maintenance preview ~ pwd quasi-language ~ QWERTY keyboard R&D ~ registration marks Registry ~ RFI RF shielding ~ run-time library SAA ~ server error server push-pull ~ soft return software ~ style sheet stylus ~ System T1 ~ ToggleKeys token ~ typography UART ~ uupc V.120 ~ view2 viewer ~ VxD w3 ~ WinG WINS ~ WWW X.25 ~ X Windows Yahoo! ~ yotta- Z39.50 standard ~ Zulu time