Computer Glossary P - Z

P - S


palm A hand-held computer.



PC Personal computer. Generally refers to computers running Windows with a Pentium processor.


PC board Printed Circuit board. A board printed or etched with a circuit and processors. Power supplies, information storage devices, or changers are attached.



PDA Personal Digital Assistant. A hand-held computer that can store daily appointments, phone numbers, addresses, and other important information. Most PDAs link to a desktop or laptop computer to download or upload information.



PDF Portable Document Format. A format presented by Adobe Acrobat that allows documents to be shared over a variety of operating systems. Documents can contain words and pictures and be formatted to have electronic links to other parts of the document or to places on the web.



Pentium chip Intel's fifth generation of sophisticated high-speed microprocessors. Pentium means “the fifth element.”



peripheral Any external device attached to a computer to enhance operation. Examples include external hard drive, scanner, printer, speakers, keyboard, mouse, trackball, stylus and tablet, and joystick.



personal computer (PC) A single-user computer containing a central processing unit (CPU) and one or more memory circuits.



petabyte A measure of memory or storage capacity and is approximately a thousand terabytes.



petaflop A theoretical measure of a computer's speed and can be expressed as a thousand-trillion floating-point operations per second.



platform The operating system, such as UNIX®, Macintosh®, Windows®, on which a computer is based.



plug and play Computer hardware or peripherals that come set up with necessary software so that when attached to a computer, they are “recognized” by the computer and are ready to use.



pop-up menu A menu window that opens vertically or horizontally on-screen to display context-related options. Also called drop-down menu or pull-down menu.



Power PC A competitor of the Pentium chip. It is a new generation of powerful sophisticated microprocessors produced from an Apple-IBM-Motorola alliance.



printer A mechanical device for printing a computer's output on paper. There are three major types of printers: Dot matrix: creates individual letters, made up of a series of tiny ink dots, by punching a ribbon with the ends of tiny wires. (This type of printer is most often used in industrial settings, such as direct mail for labeling.) Ink jet: sprays tiny droplets of ink particles onto paper. Laser: uses a beam of light to reproduce the image of each page using a magnetic charge that attracts dry toner that is transferred to paper and sealed with heat.



program A precise series of instructions written in a computer language that tells the computer what to do and how to do it. Programs are also called “software” or “applications.”



programming language A series of instructions written by a programmer according to a given set of rules or conventions (“syntax”). High-level programming languages are independent of the device on which the application (or program) will eventually run; low-level languages are specific to each program or platform. Programming language instructions are converted into programs in language specific to a particular machine or operating system (“machine language”) so that the computer can interpret and carry out the instructions. Some common programming languages are BASIC, C, C++, dBASE, FORTRAN, and Perl.



puck An input device, like a mouse. It has a magnifying glass with crosshairs on the front of it that allows the operator to position it precisely when tracing a drawing for use with CAD-CAM software.



pull-down menu A menu window that opens vertically on-screen to display context-related options. Also called drop-down menu or pop-up menu.



push technology Internet tool that delivers specific information directly to a user's desktop, eliminating the need to surf for it. PointCast, which delivers news in user-defined categories, is a popular example of this technology.



QuickTime® Audio-visual software that allows movie-delivery via the Internet and e-mail. QuickTime mages are viewed on a monitor.



RAID Redundant Array of Inexpensive Disks. A method of spreading information across several disks set up to act as a unit, using two different techniques: Disk striping: storing a bit of information across several discs (instead of storing it all on one disc and hoping that the disc doesn't crash). Disk mirroring: simultaneously storing a copy of information on another disc so that the information can be recovered if the main disc crashes.



RAM Random Access Memory. One of two basic types of memory. Portions of programs are stored in RAM when the program is launched so that the program will run faster. Though a PC has a fixed amount of RAM, only portions of it will be accessed by the computer at any given time. Also called memory.



right-click Using the right mouse button to open context-sensitive drop-down menus.


ROM Read-Only Memory. One of two basic types of memory. ROM contains only permanent information put there by the manufacturer. Information in ROM cannot be altered, nor can the memory be dynamically allocated by the computer or its operator.


scanner An electronic device that uses light-sensing equipment to scan paper images such as text, photos, and illustrations and translate the images into signals that the computer can then store, modify, or distribute.



search engine Software that makes it possible to look for and retrieve material on the Internet, particularly the Web. Some popular search engines are Alta Vista, Google, HotBot, Yahoo!, Web Crawler, and Lycos.



server A computer that shares its resources and information with other computers, called clients, on a network.



shareware Software created by people who are willing to sell it at low cost or no cost for the gratification of sharing. It may be freestanding software, or it may add functionality to existing software.



software Computer programs; also called “applications.”



spider A process search engines use to investigate new pages on a web site and collect the information that needs to be put in their indices.



spreadsheet Software that allows one to calculate numbers in a format that is similar to pages in a conventional ledger.



storage Devices used to store massive amounts of information so that it can be readily retrieved. Devices include RAIDs, CD-ROMs, DVDs



streaming Taking packets of information (sound or visual) from the Internet and storing it in temporary files to allow it to play in continuous flow.


stylus and tablet A input device similar to a mouse. The stylus is pen shaped. It is used to “draw” on a tablet (like drawing on paper) and the tablet transfers the information to the computer. The tablet responds to pressure—the firmer the pressure used to draw, the thicker the line appears.



surfing Exploring the Internet.



surge protector A controller to protect the computer and make up for variances in voltage.





T – Z


telnet A way to communicate with a remote computer over a network.



trackball Input device that controls the position of the cursor on the screen; the unit is mounted near the keyboard, and movement is controlled by moving a ball.



terabytes (TB) A thousand gigabytes.



teraflop A measure of a computer's speed. It can be expressed as a trillion floating-point operations per second.



Trojan Horse See virus.



UNIX® A very powerful operating system used as the basis of many high-end computer applications.



upload The process of transferring information from a computer to a web site (or other remote location on a network). v. To transfer information from a computer to a web site (or other remote location on a network).



URL Uniform Resource Locator. 1. The protocol for identifying a document on the Web. 2. A Web address (e.g., www.census.gov). A URL is unique to each user. See also domain.


UPS Universal Power Supply or Uninterruptible Power Supply. An electrical power supply that includes a battery to provide enough power to a computer during an outage to back-up data and properly shut down.



USB Universal Serial Bus. An industry standard for connecting different compatible peripheral devices across multiple platforms. Devices include printers, digital cameras, scanners, game pads, joysticks, keyboards and mice, and storage devices. USB peripherals offer the use of plug-and-play convenience by eliminating the need to turn off or restart the computer when attaching a new peripheral. Users can connect USB peripherals whenever they need them. For example, a user producing a newsletter could easily swap a digital camera for a scanner-without any downtime. Small, simple, inexpensive, and easy to attach, USB supports simultaneous connection of up to 127 devices by attaching peripherals through interconnected external hubs.


USB hub A multiple-socket USB connecter that allows several USB-compatible devices to be connected to a computer.



USENET A large unmoderated and unedited bulletin board on the Internet that offers thousands of forums, called newsgroups. These range from newsgroups exchanging information on scientific advances to celebrity fan clubs.



user friendly A program or device whose use is intuitive to people with a nontechnical background.



video teleconferencing A remote “face-to-face chat,” when two or more people using a webcam and an Internet telephone connection chat online. The webcam enables both live voice and video.



virtual reality (VR) A technology that allows one to experience and interact with images in a simulated three-dimensional environment. For example, you could design a room in a house on your computer and actually feel that you are walking around in it even though it was never built. (The Holodeck in the science-fiction TV series Star Trek: Voyager would be the ultimate virtual reality.) Current technology requires the user to wear a special helmet, viewing goggles, gloves, and other equipment that transmits and receives information from the computer.



virus An unauthorized piece of computer code attached to a computer program or portions of a computer system that secretly copies itself from one computer to another by shared discs and over telephone and cable lines. It can destroy information stored on the computer, and in extreme cases, can destroy operability. Computers can be protected from viruses if the operator utilizes good virus prevention software and keeps the virus definitions up to date. Most viruses are not programmed to spread themselves. They have to be sent to another computer by e-mail, sharing, or applications. The worm is an exception, because it is programmed to replicate itself by sending copies to other computers listed in the e-mail address book in the computer. There are many kinds of viruses, for example: Boot viruses place some of their code in the start-up disk sector to automatically execute when booting. Therefore, when an infected machine boots, the virus loads and runs. File viruses attached to program files (files with the extension “.exe”). When you run the infected program, the virus code executes. Macro viruses copy their macros to templates and/or other application document files. Trojan Horse is a malicious, security-breaking program that is disguised as something benign such as a screen saver or game. Worm launches an application that destroys information on your hard drive. It also sends a copy of the virus to everyone in the computer's e-mail address book.



WAV A sound format (pronounced “wave”) used to reproduce sounds on a computer.


webcam A video camera/computer setup that takes live images and sends them to a Web browser.



Window A portion of a computer display used in a graphical interface that enables users to select commands by pointing to illustrations or symbols with a mouse. “Windows” is also the name Microsoft adopted for its popular operating system.



World Wide Web (“WWW” or “the Web”) A network of servers on the Internet that use hypertext-linked databases and files. It was developed in 1989 by Tim Berners-Lee, a British computer scientist, and is now the primary platform of the Internet. The feature that distinguishes the Web from other Internet applications is its ability to display graphics in addition to text.



word processor A computer system or program for setting, editing, revising, correcting, storing, and printing text.



Worm See virus.



WYSIWYG What You See Is What You Get. When using most word processors, page layout programs (See desktop publishing), and web page design programs, words and images will be displayed on the monitor as they will look on the printed page or web page.