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P
Packet/Packet Switching
A packet is a chunk of information sent over a network. Packet switching is the process by which a carrier breaks up data into these chunks or packets. Each packet contains the address of origin, the address of its destination, and information about how to reunite with other related packets. This process allows packets from many different locations to co-mingle on the same lines and be sorted and directed to different routes by special machines along the way.
Password
A password is a code or word used to gain access to restricted data on a computer network. While passwords provide security against unauthorised users, the security system can only confirm that the password is legitimate, not whether the user is authorised to use the password. That's why it is important to safeguard passwords:
Never disclose your password.
Devise a password that consists of letters, numbers, and symbols.
Change your password frequently.
See also Security Policy
Pathname
A pathname indicates the location of a particular file or directory by outlining the route or "path" from the host name (if the file resides on a remote server) through the directory structure to the desired file name or directory name. Each name in the series of names that define a path is separated by a slash. If the file is located in the current working directory on your computer, it is referred to only by its filename.
Pathnames can be absolute or relative. An absolute pathname provides the full path (address) of a file, including the computer system, directories, and subdirectories (if any) it resides in. Relative pathnames are used to describe a file or directory location on the user's system relative to the user's current location on the system (i.e. based on which level of the directory structure the user is in).
An acronym for Portable Document Format. PDF is a file type created by Adobe Systems, Inc. that allows fully formatted, high-resolution, PostScript documents to be easily transmitted across the Internet and viewed on any computer that has Adobe Acrobat Reader software. A proprietary viewer is available for free at the Adobe site.
Corporations that have invested in brand name identification use PDF to display the original look of their logos and advertising. Publishers can create a high-quality brochure and then "publish" it as is, without converting it to HTML. Anyone interested in presenting documents with the highest possible resolution or a complex layout might choose to use PDF.
PDF files can be distributed via e-mail, web pages, CD-ROMs, online services and LANs. They can also contain hyperlinks, QuickTime movies, and sound clips.
See also HTML
PERL
An acronym for Practical Extraction and Reporting Language, PERL is a robust programming language frequently used for creating CGI programs on web servers. PERL is faster than UNIX shell script programs, it can read and write binary files, and it can process very large files. The major advantage of PERL over C as a programming language is that PERL does not need to be compiled.
Ping
Ping tests the Internet to see what systems are working. Ping can also test and record the response time of accessing other companies. This provides a systems administrator with valuable information on what networks are overloaded so access times can be optimised.
Plug-In
A plug-in extends the capabilities of a web browser, such as Netscape Navigator or Microsoft Internet Explorer, allowing the browser to run multimedia files. The term "plug-in" is used in two ways on the Internet. The technical definition of a plug-in is a small add-on piece of software that conforms to Netscape Navigator standard. Other browsers however, including Internet Explorer, support many Netscape plug-ins. But Explorer actually uses a different software standard, called an ActiveX control, instead of plug-ins.
POP
A point-of-presence (POP) is an access point to the Internet. A POP necessarily has a unique Internet Protocol (IP) address. Internet service providerS (ISP)have a point-of-presence on the Internet and probably more than one. The number of POPs that an ISP has is sometimes used as a measure of its size or growth rate. Star's outer core network comprises 12 POPs located across the UK.
See also IP Address
POP3
An acronym for Post Office Protocol Version 3), POP3 is the defacto Internet mail standard today. Mail comes into a server and is placed in a repository for the recipient. The person then contacts the server with a POP compliant client (Notes, Outlook, Eudora, Netscape Mail etc.) and downloads the mail to the local client. The mail is then stored locally.
See also POP Server
POP Server
A POP server uses the Post Office Protocol, to hold users' incoming e-mail until they read or download it.
See also POP3
Port
Port can mean two things:
1) To transfer or translate data or program files from one computer platform to another, such as from a PC to a Macintosh. Software programs usually have to be re-written to be successfully ported.
2) A connector on a computer to which peripheral devices, such as a printer or modem, can be attached. Typically, these are serial ports, parallel ports, and modem ports.
Portal
Usually used as a marketing term to described a Web site that is intended to be the first place people see when using the Web. Typically a "Portal site" has a catalogue of web sites, a search engine, or both. A Portal site may also offer e-mail and other services to entice people to use that site as their main "point of entry" (hence "portal") to the Web.
PPP
An acronym for Point-to-Point Protocol, PPP is a communications protocol used to transmit network data over telephone lines. It allows you to connect your computer to the Internet itself, rather than logging on through an Internet service provider's host computer and using UNIX commands through a shell. This type of connection lets you communicate directly with other computers on the network using TCP/IP connections. It is part of the TCP/IP suite of programs necessary to connect to and use the Internet.
See also UNIX; TCP/IP
Protocol
A protocol is the standard or set of rules that two computers use to communicate with each other. Also known as a communications protocol or network protocol, this is a set of standards that assures differing network products or programs can work together. Any product that uses a given protocol should work with any other product using the same protocol.
Proxy Server
A proxy server is a server that acts as an intermediary between a workstation user and the Internet so that the enterprise can ensure security, administrative control and caching service. A proxy server is associated with or part of a gateway server that separates the enterprise network from the outside network and a firewall server that protects the enterprise network from outside intrusion.
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