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Glossary: P
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- A convenient graphical addition to a word processor which shows a small image of what the layout of a word processed page will look like when printed, useful for noting single lines at the top or bottom or adjusting margins.
- paint software
- Graphics programs that allow users to handle prepared shapes or do freehand sketching and manipulate their creations at the pixel level.
- palmtop (hand-held)
- A small portable computer weighing one pound or less.
- paperless office
- A term used to describe a totally computerized office where all communications will be handled electronically in soft copy.
- paradigm shift
- A term for a major shift in thinking about an important subject. For instance, if the desktop model of personal computing were replaced with decentralized network computing based on the client/server model of the World Wide Web, computing would have undergone a paradigm shift.
- parallel processing
- A combination of multiple interconnected processors and software techniques that analyze input data simultaneously rather than serially; useful in neural networks.
- parallel transmission
- Method of transmitting data within a computer in which a bundled set of bits is sent over a data bus all at the same time.
- parity
- A mechanism included as part of a binary code that indicates the number of 1s in the code, used for error checking.
- parity bits
- Single bits attached to each byte to check that data are being transmitted correctly through a communications channel.
- parsing
- A linguistic term for breaking up a sentence in a natural language into its syntactical components, such as noun and verb phrases; today a lively subject of computer research.
- Pascal
- A popular structured programming language that is often taught to beginning programmers because it is relatively easy to learn.
- password system
- A software strategy of using a unique, normally secret, code to identify users before granting them access to a computer system or database for multiple users.
- pattern matching
- A computer technique for finding a predetermined pattern, such as a phrase in a long list of cliches.
- pattern matching
- The human ability to recognize underlying patterns of similarity in different contexts, such as handwriting styles and dialects, for which neural networks using fuzzy logic seem appropriate.
- personal computer (microcomputer or PC)
- The least expensive but most common type of computer system in use today, built around a microprocessor and used mainly by one person at a time.
- personal digital assistant (PDA)
- A new breed of palmtop computer designed to adapt to the user's style of working rather than requiring the person to follow the work pattern of the desktop computer.
- photo-realism
- A term used to describe the increasingly realistic creations of computer graphics made possible by techniques like ray tracing.
- pipelining
- A process to speed up the throughput of a microprocessor by staging different jobs to run concurrently rather than doing them in sequence.
- pirated software
- Programs that have been copied illegally rather than purchased legally.
- pixel
- A term made from the words picture element to describe a spot on a computer screen capable of changing color or shade. Modern graphical screens may have more than a million pixels.
- PL/I
- A high-level programming language of the 1960s designed to meet the needs of both business and science by combining the advantages of COBOL and FORTRAN.
- place system
- The basis of any number system, such as decimal or binary integers. A digit in a certain place means that the digit is raised to the power of the base number for that place. For instance, the 2 in the "tens" place in the number 20 must be multiplied by 10 to get its value.
- plotter
- An output device that creates a graphic image by controlling the motion of a pen on paper.
- plugboard
- Before programming languages were invented, programs were individually wired for one application using such a wiring board, and modification required stopping the machine for rewiring.
- portability
- Ability to run the same programs on several brands of computers, one of the attractions of the Unix operating system.
- presentation graphics
- Software that produces graphic representations of information, often used for presentations at meetings.
- Prestel
- A British videotex system that sends out computer-generated video information, such as news and weather text, piggybacked on the television signal.
- primary sort
- The first field to be sorted in a database sorting operation.
- primary storage
- The functional component of a computer where programs and data are stored for processing, normally RAM in PCs.
- printer
- The most common output device for PCs used to create printed reports.
- procedure
- In structured programming, one of a series of independent subtasks that stand alone and can be performed one at a time in a modular fashion.
- process control application
- A process in manufacturing often suitable for installation of robotic machines, such as automated welding on an assembly line.
- processing cycle
- The implementation of the throughput process from input to output, which requires a partnership of hardware and software in carrying out the five functions of all computer applications.
- processing
- Manipulation of data by a computer that results in quick and efficient information.
- processor
- The functional element of a computer system for processing, incorporated in personal computers in the microprocessor chip.
- production rule
- An if/then condition incorporated into the inference engine of an expert system.
- productivity software
- A general term to apply to the most common kinds of applications software to increase a user's productivity: word processors, spreadsheets, database systems, graphics, data communications.
- program
- A set of instructions that tells a computer what to do. Programs are often read from a diskette or a hard drive but sometimes are already resident in the computer's central memory.
- Prolog
- A popular logic programming language for expert systems and other artificial intelligence research procedures like natural language processing.
- proportional spacing
- A fine printing option of variable spacing between letters for a pleasant visual effect, common in typesetting and available with some full-featured word processors.
- prosthetics
- The field of replacing missing body parts with artificial limbs or organs, today being developed with computerized devices.
- pseudocode
- A kind of structured English used to describe the algorithmic steps needed in a program, analogous to a flowchart as a planning tool for programming.
- public key (PK) cryptography
- A kind of software algorithm based on pairs of numerical keys, one public and one private, for encrypting e-mail and other network transactions.
- puff switch
- A small device for people who cannot use their hands on a keyboard or mouse to select items on a computer screen by blowing softly on the switch, used in conjunction with a head pointer.
- pull-down menu
- A menu of command options that is hidden from view until revealed by a combination of keystrokes or depression of a mouse.
- punch card
- Invented for compiling the Census of 1890, an early means of encoding data for computers and other data processing equipment using a code made up of patterns of punched holes in a card.