P

Platform
A computer operating system such as Sun, Unix, Windows, or Macintosh.
Plug-ins
Small applications that add new functionality, multimedia, or audio-video capability to a program.
POP3 (Post Office Protocol, version 3)
A POP3 server acts as your email Post Office. You use an email client, like Eudora or those built-in to Netscape Navigator and Microsoft Internet Explorer, to retrieve your mail to your local drive using the POP3 protocol.
Port
To translate a computer application into another computer languages o it can be read on another operating system, or platform.
PSAPI (Presentation Space Application Programming Interface)
A protocol for accessing an IBM host. Java support for PSAPI allows developers to establish connections to an IBM host without launching a terminal window.
PROFS
The messaging protocol used for IBM mainframe-based email systems. Support for PROFS (which stands for Professional Office System) allows Netscape Messenger to exchange email with corporate email systems.
Push
A software program that retrieves information from web sites and deposits a copy on the user's computer to view offline. This is in contrast to traditional pull technology, where the user must manually seek and find information on the World Wide Web. See also channel.


POP
An acronym for Point of Presence, POP is a service provider's location for connecting to users. Generally, POPs refer to the location where people can dial into the provider's host computer. Most providers have several POPs to allow low-cost access via telephone lines.
POTS
This is an acronym for Plain Old Telephone Service.
PPP
The abbreviation for Point-to-Point Protocol, PPP is an Internet connection where phone lines and a modem can be used to connect a computer to the Internet.
Protocol
A set of standards that define how traffic and communications are handled by a computer or network routers.

Packet
See TCP/IP Packet.

Page Hits
The number of times a web page has been visited by a user.

Page Impressions
The same as Page Hits.

Page Views
The same as Page Hits.

PDF (Portable Document Format)
A document file format developed by Adobe. Most often used for text documents.

Perl (Practical Extraction and Reporting Language)
A scripting language for web servers. Most often used on Unix servers.

PHP (PHP: Hypertext Preprocessor)
A technology allowing the insertion of server executable scripts in web pages. Mostly for Unix, Linux and Solaris platforms.
Learn more about PHP in our PHP tutorial.

Ping
A method used to check the communication between two computers. A "ping" is sent to a remote computer to see if it responds.

Platform
In web terms: The computer's operating system like Windows, Linux, or OS X.

Plug-In
An application built into another application. In web terms: A program built in (or added) to a web browser to handle a special type of data like e-mail, sound, or movie files. (See also ActiveX)

PNG (Portable Network Graphics)
A format for encoding a picture pixel by pixel and sending it over the web. A W3C recommendation for replacing GIF.

POP (Post Office Protocol)
A standard communication protocol for retrieving e-mails from an e-mail server. (See also IMAP).
Learn more about POP and IMAP in our TCP/IP tutorial

Port
A number that identifies a computer IO (input/output) channel. In web terms: A number that identifies the I/O channel used by an Internet application (A web server normally uses port 80).

Protocol
See Communication Protocol.

PPP (Point to Point Protocol)
A communication protocol used for direct connection between two computers.

Proxy Server
An Internet server dedicated to improve Internet performance.

Page

Name for a basic web document. Websites usually consist of many (web) pages.

PAP

(Password Authentication Protocol). PAP is the authentication protocol used over PPP connections.

Peer-to-Peer network

A peer-to-peer network is a collection of computers that can communicate and share information, but that don't have any kind of hierarchical structure. This is the opposite of the client/server model.

Perl

Open source CGI scripting programming language. Written in 1987. Still one of the most popular web programming languages mostly due to its powerful text-manipulation facilities. A huge number of Perl scripts are available for download.

PHP

PHP is an free, open-source server-side scripting language. PHP code can be embedded in HTML. PHP files usually have extensions like .php or .php3. PHP language style is similar to C and Java. Here is the PHP group web site. Other popular server-side scripting languages are ASP, Perl, ColdFusion, TCL, Python, and JSP.

PKZIP or PKUNZIP

Popular compression and decompression programs.

Plug-in

An add-on piece of software that can extend the features of an existing application. For example Netscape browser plug-ins allow displaying of new types of web content, that the browser can't display on its own.

POP

Post Office Protocol. Popular but inflexible email retrieval standard. All messages are downloaded at the name time and can only be manipulated on a client machine. Current version is POP3. Also see IMAP.

Port

A socket on the computer or other network device used to connect it to the network.

PPP

(Point to Point Protocol) A network protocol widely used to connect computers to the Internet. Most often used on a telephone line.

PRI

(Primary Rate Interface). One of the two ISDN access methods. 23 of 64 Kbps B channels and 1 64 Kbps D channel constitute a PRI.

Protocol

A set of rules by following which two parties can communicate. The TCP/IP protocol suite is the basis of todays Internet.

PSTN

(Public Switched Telephone Network). The set of all the traditional telephone lines and all the infrastructure that comes with it.

Python

Interpreted programming language, sometimes offered by hosts for server-side scripting. Here is the Python home page.