National Teaching and Learning Change ProgrammeInformation and Communication Technology:
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• package
  Software program or programs designed for a particular application or job, such as word processing or accounts.
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• packet switching system (PSS)
  A method of sending data over a wide area network. Packet switching networks are available for general use in most countries. A packet is a group of bits, made up of data, the destination address for the data, etc. In a given situation the size of a packet may be fixed. Since each packet occupies a channel for only a short time, this arrangement provides for very efficient use of the system. Error checking should ensure that errors are detected, and that appropriate recovery procedures are automatically started. If there is an error, it will only be in a small part of the data, and this can be retransmitted quickly.
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• page
  In a word processor, a document is split into pages, as in a book.
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• page breaks
  Page breaks are a method of creating a separation between one page and the next.
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• page description language
  A high-level computer language used to pass instructions to printers for setting up the data to be printed. For example, Postscript is a page description language used by some laser printers for complex graphics and desk-top publishing. The computer will code its printout requirements, for example the size, direction and style of a piece of text or the format of a diagram. These will then be interpreted by the Postscript translator into the corresponding image of dots ready for printing. The Postscript translator is held as software in a processor in the printer.
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• page down
  A key available on most keyboards which allows you to move down to display information below that currently displayed on the screen.
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• page feed
  In a printer, the paper feed mechanism is the means of making the paper move through the printing process. Many printers require line feed, where the paper is moved after a line (or sometimes half a line) has been printed, compared with, for example, laser printers which eject one page at a time, known as page feed.
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• page setup
  In a word processor and other applications, the page setup options allow you to specify certain parameters for a particular document, e.g. orientation, margins, paper size, etc.
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• page up
  A key available on most keyboards which allows you to move up to display information above that currently displayed on the screen.
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• pagination
  The numbering of pages.
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• palette
  The range of distinct colours that a computer system can produce. No computer system will be able to produce every possible shade of colour and the palette is the total set of shades available. Most computers have a palette of sixteen million colours, though some programs will use fewer.
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• palmtop computer
  A palmtop computer is a pocket-sized device, without a conventional keyboard, which can be hand-held. It is accessed through a pen-like stylus moving over the display, and the software recognises handwriting.
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• paper size
  The dimensions of the paper, which in the UK is measured as A1, A2, A3, A4, A5 and A6. Most printers use A4 paper as standard.
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• paragraph
  One or more sentences in a block. The next paragraph starts on a new line.
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• parallel data transmission
  Parallel data transmission sends the bits for a character simultaneously along separated data lines. This means that an 8-bit code will require a minimum of 9 channels for parallel transmission (eight data and at least one ground, return channel).
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• parallel running
  This is where a new system operates for a short time alongside the old system. The results are compared to make sure the new system is working correctly.
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• parameter
  Information about a data item being supplied to a function or procedure when it is called.
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• parameter passing
  A parameter is information about a data item being supplied to a function or procedure when it is called. With a high-level language the parameters are generally enclosed in brackets after the procedure or function name. The data can be a constant or the contents of a variable. When the function or procedure is used, the calling program must pass parameters to it (parameter passing).
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• parasitic virus
  A type of virus which hides itself by attaching to a file that already exists until a specific event causes the virus to become active.
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• parent node
  A tree is a non-linear data structure where the data items can be thought of as occurring at different levels. There are links between items at one level and their descendants at the next. The data items are usually called nodes with the links known as branches. A node may have any number of descendants but itself may only be the descendant of one other node. A parent node is the node immediately above a given node, at the next level up. There can only be one parent node for each node, but different nodes, known as child nodes, may share the same parent.