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BASICS TUTORIAL ON PCS AND USE OF THE INTERNET
GLOSSARY OF TERMS USED IN THE PC AND INTERNET WORLD
GLOSSARY (p-r)
P2P:
Packet: The unit of data sent across a network. 'Packet' is a generic term used to describe a unit of data at all levels of the protocol stack, but it is most correctly used to describe application data units.
Packet InterNet Groper (PING): A program used to test reachability of destinations by sending them an ICMP echo request and waiting for a reply. The term is used as a verb: 'Ping host X to see if it is up!' See also: Internet Control Message Protocol.
Packet switching: A communications paradigm in which packets (messages) are individually routed between hosts, with no previously established communication path. See also: Circuit switching, Connection-oriented, Connectionless.
Page:
Parallel Port (LPD1 or 2):
Password:
PC:
PCB:
PCI: See Peripheral Component Interconnect.
PD: Public Domain.
Peripheral Component Interconnect (PCI): A local bus standard developed by Intel Corporation. Most modern PCs include a PCI bus in addition to a more general ISA expansion bus. It is believed that PCI will eventually supplant ISA entirely (and VESA, EISA, and VLB). PCI Version 1.0 is a 32-bit bus that runs at a clock speed of 33 MHz. This yields a throughput rate of 132 megabytes per second. PCI 2.0 is a 64-bit bus running at a clock speed of 66 MHz. Although it was developed by Intel, PCI is not tied to any particular family of microprocessors. In fact, in a strict sense, it is not a local bus at all, because it does not connect directly with the microprocessor. For this reason, some experts refer to it as a 'mezzanine bus'.
Perl:
PHP:
PING: See: Packet INternet Groper.
Pixel:
Point Of Presence (POP): A site where there exists a collection of telecommunications equipment, usually digital leased lines and multi-protocol routers.
POP: Two meanings. See: Post Office Protocol and Point Of Presence
Port: A port is a transport layer demultiplexing value. Each application has a unique port number associated with it. See also: Transmission Control Protocol.
Post Office Protocol (POP): A protocol designed to allow single user hosts to read mail from a server. There are three versions: POP, POP2, and POP3. Later versions are not compatible with earlier versions. See also: Electronic Mail.
Postmaster: On a particular site, a Webmaster is the person responsible for taking care of electronic mail problems, answering queries about users, and other related work. See also: Electronic Mail.
Program/Programming:
Protocol: A formal description of message formats and the rules two computers must follow to exchange those messages. Protocols can describe low-level details of machine-to-machine interfaces, eg the order in which bits and bytes are sent across a wire, or high-level exchanges between allocation programs, eg the way in which two programs transfer a file across the Internet.
Queue: (in data transmission) a backup of packets awaiting processing.
Random Access Memory (RAM): RAM is hardware inside a PC that retains programs and data on a short-term basis and stores information while you work. RAM is working memory and one of the factors that make your computer run faster, because read/write access to it is much faster than to the Hard Disk Drive (qv). It comes in 32-bit, 64-bit, 128-bit, 256-bit, and higher, and additional 'blocks' of RAM can be added to handle more Applications (qv) simultaneously, depending on your computer.
Read Only Memory (ROM): ROM is built-in computer memory that can be read from but not written to in normal usage. Variations include Programmable ROM (PROM) and Erasible PROM (EPROM). In a PC, ROM contains the programmed firmware (qv) that allows your computer to boot up each time you turn it on, and it contains essential system programs (in this application, EPROM is used and various options made available in the firmware can be changed by entering 'System Setup' during the boot-up process, eg by pressing F8). Unlike a computer's Random Access Memory (RAM), ROM does not lose its data when power is turned off. See also: Random Access Memory.
Reassembly: (in data transmission) the IP process in which a previously fragmented packet is reassembled before being passed to the transport layer. See also: Fragmentation.
Redundancy:
Regional: See: Mid-level network.
Registers:
Remote login: Operating on a remote computer, using a protocol over a computer network as though locally attached. See also: Telnet.
Remote Procedure Call (RPC): An easy and popular paradigm for implementing the client-server model of distributed computing. In general, a request is sent to a remote system to execute a designated procedure, using arguments supplied, and the result returned to the caller. There are many variations and subtleties in various implementations, resulting in a variety of different (incompatible) RPC protocols.
Resolution:
Router: A device which forwards traffic between networks. The forwarding decision is based on network layer information and routing tables, often constructed by routing protocols. See also: Bridge, Gateway.
Routing: The process of selecting the correct interface and next hop for a packet being forwarded. See also: Hop, Router.
RPC: See: Remote Procedure Call.
Details updated: June 15 2010
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