Glossary terms provided by TechTerms.com.
| Word | Description |
| P2P | Stands for "Peer to Peer." In a P2P network, the "peers" are computer systems which are connected to each other via the Internet. Files can be shared directly between systems on the network without the need of a central server. In other words, each computer on a P2P network becomes a file server as well as a client. The only requirements for a computer to join a peer-to-peer network are an Internet connection and P2P software. Common P2P software programs include Kazaa, Limewire, BearShare, Morpheus, and Acquisition. These programs connect to a P2P network, such as "Gnutella," which allows the computer to access thousands of other systems on the network. Once connected to the network, P2P software allows you to search for files on other people's computers. Meanwhile, other users on the network can search for files on your computer, but typically only within a single folder that you have designated to share. While P2P networking makes file sharing easy and convenient, is also has led to a lot of software piracy and illegal music downloads. Therefore, it is best to be on the safe side and only download software and music from legitimate websites. |
| P2V (Physical to Virtual) migration | The operation of migrating an operating system and every application installed on it from a physical computer to a virtual machine (or a partition), without reinstalling anything. The opposite of V2P (Virtual to Physical) migration. |
| Packet | This is a small amount of computer data sent over a network. Any time you receive data from the Internet, it comes to your computer in the form of many little packets. Each packet contains the address of its origin and destination, and information that connects it to the related packets being sent. The process of sending and receiving packets is known as "packet-switching." Packets from many different locations can be sent on the same lines and be sorted and directed to different routes by various computers along the way. It works a lot like the post office, except billions of packets are transferred each day, and most packets take less than a few seconds to reach their destination. Even FedEx same-day delivery can't compete with that. |
| Packet Filter | Anything that filters out network traffic based on a sender’s address, receiver’s address, and the type of protocol being sent. Some routers support packet filtering, all firewalls do, and some proxy servers do as well. |
| Packet InterNet Gopher (PING) | Part of the standard TCP/IP suite of protocols that allows you to check your connectivity with other devices, or to check whether your own TCP/IP stack is working properly. Normally you type in something like “ping 10.250.250.37″ or “ping www.geek.com,” and you either get a response from that IP address or not. PING is extremely useful for debugging network problems |
| Packet Switched Network | A packet switched network is where individual packets each follow their own paths through the network from one endpoint to another. |
| Packet Switching | The method used to move data around on the Internet. In packet switching, all the data coming out of a machine is broken up into chunks, each chunk has the address of where it came from and where it is going. This enables chunks of data from many different sources to co-mingle on the same lines, and be sorted and directed along different routes by special machines along the way. This way many people can use the same lines at the same time. You might think of several caravans of trucks all using the same road system to carry materials. See also: Internet (Upper case I), Router |
| PACKET, PACKET JAM | When you retrieve a document via the WWW, the document is sent in "packets" which fit in between other messages on the telecommunications lines, and then are reassembled when they arrive at your end. This occurs using TCP/IP protocol. The packets may be sent via different paths on the networks which carry the Internet. If any of these packets gets delayed, your document cannot be reassembled and displayed. This is called a "packet jam." You can often resolve packet jams by pressing STOP then RELOAD. RELOAD requests a fresh copy of the document, and it is likely to be sent without jamming. |
| Page Fault | This is not an error, as “fault” would usually indicate. It simply means that the computer had to resort to using the swap file as memory. If you are getting a lot of page faults you should upgrade your system’s memory. |
| Page Orientation | Page orientation describes the way a document is printed or displayed on a screen. The two main types are "Portrait," in which the height is longer than the width, and "Landscape," in which the width is longer than the height. Most printers print in portrait mode by default, which means the page is printed vertically from top to bottom. Some programs allow the user to change the orientation to landscape mode within the "Page Setup" window. |
| Page View | Each time a user visits a Web page, it is called a page view. Page views, also written "pageviews," are tracked by website monitoring applications to record a website's traffic. The more page views a website has, the more traffic it is receiving. However, since a page view is recorded each time a Web page is loaded, a single user can rack up many page views on one website. Therefore, unique page views are commonly tracked to log the number of different visitors a website receives in a given time period. Page views are commonly confused with website hits. While people often use the term "hit" to describe a page view, technically a hit is recorded for each object that loads during a page view. For example, if a Web page contains HTML, two images, and a JavaScript reference, a single page view will record four hits. If a page contains over two hundred images, one page view will record over two hundred hits. Page views are more similar to impressions, which are commonly tracked by online advertisers. Page views and impressions may be identical if one advertisement is placed on each page. However, if multiple ads are positioned on each page, the number of ad impressions will be greater than the number of page views. |
| Paging | The act of moving pages of memory from RAM to virtual memory on a hard drive. Excessive paging is caused by a lack of actual system memory. In this case the system has to use the hard drive as memory frequently, and performance is degraded. |
| PAL | Phase Alternating Line. PAL is the name of the analogue television standard used in Westren Europe, Australisa, New Zealand and parts of Asia. A PAL picture is made of 625 scan lines of which 575 are visible. cf NTSC, SDTV, HDTV |
| palette | The range of colors a computer or an application is able to display. Most newer computers can display as many as 16 million colors, but a given program may use only 256 of them. Also refers to a display box containing a set of related tools within a desktop publishing or graphics design program. |
| PAN | 1. Personal Area Network. A wireless network that covers a few meters around a person's workspace. A PAN is used for communication between personal devices, such as bluetooth devices like wireless keyboards, headphones, cell phones etc. 2. Pan. To turn or rotate a camera horizontally - to give a panorama view, from which the abbreviation "pan" comes. 3. Pan. To move a camera or map vertically or horizontally. Panning a camera would be to move it left, right, up or down. To pan a map (or pan across a map) would be to move the area of view up, down, left or right. Whilst "pan" may technically mean a horizontal movement, it is generally taken to mean movement along any axis. |
| Para-virtualization | An enhancement of virtualization technology, where guest OSes need to be adapted (recompiled) before being ready for installation inside virtual machines. It reduces virtualization overhead and improves performances. It's an alternative approach to Binary Translation (BT). |
| Parallel ATA | Traditionally simply known as IDE. Utilizes 40 parallel signal cables for data transfer between the IDE disk drive and the IDE controller. cf Serial ATA. |
| Parallel Port | This interface is found on the back of older PCs and is used for connecting external devices such as printers or a scanners. It uses a 25-pin connector (DB-25) and is rather large compared to most new interfaces. The parallel port is sometimes called a Centronics interface, since Centronics was the company that designed the original parallel port standard. It is sometimes also referred to as a printer port because the printer is the device most commonly attached to the parallel port. The latest parallel port standard, which supports the same connectors as the Centronics interface, is called the Enhanced Parallel Port (EPP). This standard supports bi-directional communication and can transfer data up to ten times faster than the original Centronics port. However, since the parallel port is a rather dated technology, don't be surprised to see USB or Firewire interfaces completely replace parallel ports in the future. |
| Parity | The use of an extra bit on memory chips that serves as a checksum, and can let the operating system know if single-bit memory errors are occurring. |
| Parity Memory | Memory that contains a summary of its stored information. The parity does not exactly have a copy of the original, but just enough information to verify the integrity of the original. |
| Parse (v. to parse) | The act of separating data into more easily understood chunks. |
| Parser | Strictly speaking, this is something that separates data into more easily understood chunks. More practically, a parser is the part of a compiler that goes through a program and cuts it into identifiable chunks before translation. Assuming that a parser is written reliably, if the parser cannot parse a program then the program contains syntax errors. |
| Partition | A partition is a section of a hard disk. When you format a hard disk, you can usually choose the number of partitions you want. The computer will recognize each partition as a separate disk, and each will show up under "My Computer" (Windows) or on the desktop (Macintosh). So why would you want to create multiple partitions? Well, there are two main reasons. One is if you want to have multiple operating systems on your computer. Typically, an operating system needs to be installed on its own partition so that it won't conflict with other operating systems on the machine. The other reason is that multiple partitions can improve the efficiency of your hard disk. On larger disks, the cluster or block size (which is the minimum amount of space a file can take up), is larger than on small disks. This can result in a waste of disk space if you have a lot of small files. So creating multiple partitions can actually give you more space. Yep, more room for all those MP3s. "Partition" can also be used as a verb, meaning to create multiple partitions. |
| Partitioning | A software technology able to create multiple instances of the same host OS, called partitions, instead of reproducing multiple different physical machines like in virtualization. |
| Pascal | A programming language that was designed to teach computer science students the concepts of programming. It’s almost like C for dummies. In fact, the two languages are very similar, but the stoic brackets of C are changed to happy and fluffy “Begin” and “End” statements. Also, many of the more complex functions of C are missing, but Pascal is still a fully functional language. Borland used Pascal as the basis for its Delphi programming language. |
| Password | A code used to gain access (login) to a locked system. Good passwords contain letters and non-letters and are not simple combinations such as virtue7. A good password might be: 5%df(29) But don't use that one! |
| Password Authentication Protocol (PAP) | Password Authentication Protocol is a simple, weak authentication mechanism where a user enters the password and it is then sent across the network, usually in the clear. |
| Password Cracking | Password cracking is the process of attempting to guess passwords, given the password file information. |
| Password Sniffing | Passive wiretapping, usually on a local area network, to gain knowledge of passwords. |
| Paste | Just like you can paste a note on a sheet of paper, you can paste data into a document on a computer. The paste function can be used to paste copied data into text documents, images, Web browser address fields, and just about any place where you can enter data. However, to paste data, you first need to copy it to the "Clipboard," which is a temporary storage area in your system's memory, or RAM. This is done by first selecting the data you want to copy and then choosing "Copy" from the program's Edit menu. Once you have data copied to the Clipboard, you can paste it within the same document or within a different document in the same program. You can even paste copied data into a document within a different program. However, you can typically only paste data into a document with the same kind of data. For example, you cannot paste an image into your Web browser's address field or an audio file into image editing program. To paste a copied piece of data, select "Paste" from the Edit menu in the program you wish to paste the data in. Text documents or programs with text fields will typically paste the data wherever the flashing cursor is. You can also use the keyboard shortcut "Control-V" for Windows or "Command-V" for the Mac OS to paste the data. The reason the "V" key is used is because the "P" key is usually reserved for the "Print" shortcut and "V" is right next to the "C" key, which is used for copying. So it might not be that intuitive at first, but it makes sense when you think about it. =) |
| PATA | Abbreviation for Parallel ATA. PATA is the term now commonly used for what historically was termed simply IDE. PATA has a maximum data transfer rate of 133MB/sec. See ATA for details. cf SATA. |
| Patch | Minor updates to programs that are distributed with only the changes and not the whole program. Imagine an instruction manual that has an extra page stapled in it with a correction of some text for that page. That is what would be considered a patch. |
| Patch cable | The common name for any network cable that is used to connect, or “patch,” any two network ports. |
| Patch panel | A group of network ports stuck together for easy accessibility. Usually this panel resides in a wiring closet or server room. Connections are made between this panel and ports on a hub to enable a network connection at a remote port. Each port on the patch panel is connected by a longer cable (often run through the ceiling) to a remote port anywhere in an office that needs a computer hooked up to the network.Patch panels offer the convenience of allowing technicians to quickly change the path of select signals, without the expense of dedicated switching equipment. This was first used by early telephone exchanges, where the telephone switchboard (a massive array of patch panels) and a large room full of telephone operators running it was ubiquitous. |
| Patching | Patching is the process of updating software to a different version. |
| Path | A path, also known as a "file path" or "directory path," defines the location of a file or folder. Paths can either be relative or absolute. Relative paths describe file and folder locations from the current directory, such as "pdfs/instructions.pdf." Absolute paths define locations of files and folders from the root directory, such as "/Users/[username]/Documents/pdfs/instructions.pdf." Both relative and absolute paths are useful in describing the location of files and folders within a computer's file system. |
| Pay-Per-Click Fraud | Pay-Per-Click Fraud The repetitive clicking on ads on a website in order to generate revenue for the website. Websites which run advertisements on the pay-per-click model are paid an amount each time someone clicks on an advertisement, with pay-per-click fraud the website arranges for clicks to be made on those advertisements purely for the purposes of raising revenue for the website. This is a fraud because the advertisers receive no benefit but see their advertising budget fraudulently eaten away. |
| Payload | The eventual action taken by a virus once it has installed itself on a system. This action may be immediate, or it could wait for some trigger in the future, such as a specific date or a certain amount of time, to take action. The possible actions of a virus are limited to your imagination, although some payloads include deletion of files, formatting hard drives, or simply displaying a message to the user. |
| PB | 1. Abbreviation for Petabyte. 250) bytes. 2. Abbreviation for Play Back. |
| PBR | Policy Based Routing. |
| PBX | Private Branch Exchange. |
| PC | 1. Personal Computer. A computer designed for use by one person at a time. 2. Abbreviation for pieces. For example 2 pc means 2 piece (or 2 pieces). |
| PC Card | A newer synonym for PCMCIA Card. |
| PC100 (PC100 SDRAM) | The standard that SDRAM makers adhere to to be sure that SDRAM running at 100MHz works properly. PC100 SDRAM normally works fine in 66MHz SDRAM motherboards. |
| PC100 SDRAM | The standard that SDRAM makers adhere to to be sure that SDRAM running at 100MHz works properly. PC100 SDRAM normally works fine in 66MHz SDRAM motherboards. |
| PC1066 RDRAM | Rambus RDRAM that runs at a speed of 533MHz double-pumped to an effective speed of 1.06GHz. Memory throughput in systems featuring this type of DRAM is 2.1GB/second per 16-bit channel, or 4.2GB/second per 32-bit channel. |
| PC133 (PC133 SDRAM) | A type of SDRAM that is designed to be run at 133MHz operation. It is pin-compatible with PC100 SDRAM and 66MHz SDRAM, and comes in a DIMM form factor. |
| PC133 SDRAM | A type of SDRAM that is designed to be run at 133MHz operation. It is pin-compatible with PC100 SDRAM and 66MHz SDRAM, and comes in a DIMM form factor. |
| PC1600 (PC1600 DDR SDRAM) | DDR SDRAM running at 100MHz double-pumped to an effective speed of 200MHz. It has a maximum data transfer rate of 1.6GB/second for one PC1600 channel. |
| PC200 DDR SDRAM | The DDR memory chips used to assemble PC1600 DDR memory modules. |
| PC2100 DDR SDRAM | A type of DDR SDRAM running at 133MHz double-pumped to an effective speed of 266MHz. It is referred to as PC2100 because systems featuring DDR SDRAM at 266MHz have a maximum data transfer rate of 2.1GB/second. |
| PC266 DDR SDRAM | The DDR memory chips used to assemble PC2100 DDR memory modules. |
| PC2700 (PC2700 DDR SDRAM) | A type of DDR SDRAM running at 166MHz double-pumped to an effective speed of 333MHz. It is referred to as PC2600 because of its maximum data transfer rate of 2.7GB/second. |
| PC3200 (PC3200 DDR SDRAM) | A type of DDR SDRAM running at 200MHz double-pumped to an effective speed of 400MHz. It is referred to as PC3200 because of its maximum data transfer rate of 3.2GB/second in a single 64-bit channel. |
| PC333 DDR SDRAM | The DDR memory chips used to assemble PC2700 DDR memory modules. |
| PC400 DDR SDRAM | The DDR memory chips used to assemble PC3200 DDR memory modules. |
| PC600 RDRAM | Rambus RDRAM that runs at a speed of 266MHz double-pumped to an effective speed of 532MHz. Memory throughput in systems featuring this type of DRAM is about 1.06GB/second. |
| PC700 RDRAM | Rambus RDRAM that runs at a speed of 356MHz double-pumped to an effective speed of 712MHz. Memory throughput in systems featuring this type of DRAM is about 1.42GB/second. |
| PC800 RDRAM | Rambus RDRAM that runs at a speed of 400MHz double-pumped to an effective speed of 800MHz. Memory throughput in systems featuring this type of DRAM is 1.6GB/second. |
| PCB | Printed Circuit Board. See also PWB. |
| PCI | 1. Peripheral Computer Interface. A 32 or 64 bit bus architecture described by the PCI Local Bus Specification. cf ISA. 2. Payment Card Industry. 3. Payment Card Industry (PCI) Data Security Standard. See PCI DSS |
| PCI Express | First came PCI, then PCI-X, then PCI Express. PCI Express can be abbreviated as PCIe or, less commonly and more confusingly, PCX. Unlike earlier PCI standards, PCI Express does not use a parallel bus structure, but instead is a network of serial connections controlled by a hub on the computer's motherboard. This enables PCI Express cards to run significantly faster than previous PCI cards. Because the PCI Express interface is a serial connection, it does not have a speed measured in Megahertz, like PCI or PCI-X. Instead, its performance is measured in data throughput speeds, which are several times faster than PCI-X. Furthermore, PCI Express is available in x1, x4, x8, and x16 implementations, which increases the bandwidth by the corresponding amount. However, larger implementations require longer PCI Express slots. For example, a x4 slot is larger than a x1 slot and a x16 slot is larger than a x8 slot. A PCI Express card can be inserted in any slot that is large enough for it. For example, a x8 card could be inserted into a x16 slot, but a not a x1 or x4 slot. Since PCI Express connections can support such fast data transfer rates, they can be used to connect high-speed devices such as Gigabit Ethernet cards and high-end video cards. For this reason, PCI Express is expected to replace both PCI and AGP connections. Fortunately, PCI Express was designed to be backwards compatible with both PCI hardware and software. However, to use a PCI Express card, your computer must have at least one available PCI Express slot. |
| PCI-X | Stands for "Peripheral Component Interconnect Extended." Once again, "Ex" is abbreviated with an "X" instead of an "E." Most desktop computers include one or more PCI slots for expanding the computer's I/O capabilities. Common PCI cards include network cards, sound cards, and video cards. In the early 1990s, when PCI was first introduced, the 66 MHz speed of PCI was more than sufficient for PCI cards available at the time. However, a decade later, expansion cards supported much faster data transfer rates and therefore became faster than the PCI bus would support. To prevent the interface from becoming a bottleneck, PCI-X was introduced. The first version of PCI-X supported data transfer rates of 133 MHz, which is more than twice as fast as the original PCI standard. Then along came PCI-X 2.0, which can run at speeds of 266 or 533 MHz. These speeds are fast enough to support Gigabit Ethernet cards and video capture devices without slowing them down. PCI-X cards can only be installed in PCI-X slots, but the slots themselves are backwards compatible with PCI cards. |
| PCMCIA | Stands for "Personal Computer Memory Card International Association." It can also mean, perhaps more appropriately, "People Can't Memorize Computer Industry Acronyms." This way-to-long acronym stands for an association founded in 1989 which develops standards for expansion cards for portable computers. However, the term is most commonly associated with the actual cards standardized by the organization. These cards are referred to as "PCMCIA cards," or simply "PC cards." There are three types of PCMCIA cards, all of which are rectangular and measure 8.56 by 5.4 cm., but have different widths: Type I: up to 3.3 mm. thick, mainly used to add additional ROM or RAM. Type II: up to 5.5 mm. thick, typically used for fax/modem cards. Type III: up to 10.5 mm. thick, often used to attach portable disk drives. PCMCIA slots also come in three sizes -- a Type I slot can hold one Type I card, a Type II slot can hold one Type II card or two Type I cards, and a Type III slot can hold one Type III card or one Type I and one Type II card. PC Cards can be removed or inserted "on the fly," which means you don't have to turn your computer off to exchange them and you don't have to restart for your computer to recognize them. |
| PDA | Personal Digital Assistant. A generic term used to describe any small portable hand-held electronic device that provides a minimum of storage and retrieval functions, such as calendar and address book. PDAs are also referred to as hand-held computers. |
| Portable Document Format (file). A document format developed by Adobe, for storing and formatting published documents. PDF files are recognised by the file extension .pdf. | |
| peer-to-peer | A type of connection between two computers; both perform computations, store data, and make requests from each other (unlike a client-server connection where one computer makes a request and the other computer responds with information). |
| Penetration | Gaining unauthorized logical access to sensitive data by circumventing a system's protections. |
| Penetration Testing | Penetration testing is used to test the external perimeter security of a network or facility. |
| Peripheral | A computer peripheral is any external device that provides input and output for the computer. For example, a keyboard and mouse are input peripherals, while a monitor and printer are output peripherals. Computer peripherals, or peripheral devices, are sometimes called "I/O devices" because they provide input and output for the computer. Some peripherals, such as external hard drives, provide both input and output for the computer. |
| Perl | Practical Extraction and Reporting Language. A common scripting language used on both Windows and UNIX platforms. It was originally popular on UNIX platforms but is now common on Windows systems, particularly for server scripting. Commonly used for creating CGI programs to generate dynamic pages on web servers. Perl was first developed back in 1986 by Larry Wall, and first released the following year. Other names were considered before "Perl" was adopted as the name (including his wife's name "Gloria", and Pearl). The definition "Practical Extraction and Reporting Language" came after the language was first developed. |
| Permalink | A "permanent link" to a particular posting in a blog. A permalink is a URI that points to a specific blog posting, rather than to the page in which the posting original occured (which may no longer contain the posting.) |
| Permutation | Permutation keeps the same letters but changes the position within a text to scramble the message. |
| Persistent disk mode | All disk writes issued by software running inside a virtual machine are immediately and permanently written to a persistent virtual disk. As a result, a virtual disk or raw disk in persistent mode behaves like a conventional disk drive on a real computer. |
| PERSONAL PAGE | A web page created by an individual (as opposed to someone creating a page for an institution, business, organization, or other entity). Often personal pages contain valid and useful opinions, links to important resources, and significant facts. One of the greatest benefits of the Web is the freedom it as given almost anyone to put his or her ideas "out there." But frequently personal pages offer highly biased personal perspectives or ironical/satirical spoofs, which must be evaluated carefully. The presence in the page's URL of a personal name (such as "jbarker") and a ~ or % or the word "users" or "people" or "members" very frequently indicate a site offering personal pages. |
| Petabyte | Unit of storage. Sometimes abbreviated to PB. 1 petabyte = 2 to to the fiftieth power (250) bytes = 1,125,899,906,842,624 bytes = 1024 terabytes. |
| PFW | Personal Firewall. A firewall intended to protect a single PC. Usually a software firewall. |
| Pharming | Pharming is yet another way hackers attempt to manipulate users on the Internet. While phishing attempts to capture personal information by getting users to visit a fake website, pharming redirects users to false websites without them even knowing it. While a typical website uses a domain name for its address, its actual location is determined by an IP address. When a user types a domain name into his or her Web browser's address field and hits enter, the domain name is translated into an IP address via a DNS server. The Web browser then connects to the server at this IP address and loads the Web page data. After a user visits a certain website, the DNS entry for that site is often stored on the user's computer in a DNS cache. This way, the computer does not have to keep accessing a DNS server whenever the user visits the website. One way that pharming takes place is via an e-mail virus that "poisons" a user's local DNS cache. It does this by modifying the DNS entries, or host files. For example, instead of having the IP address 17.254.3.183 direct to www.apple.com, it may direct to another website determined by the hacker. Pharmers can also poison entire DNS servers, which means any user that uses the affected DNS server will be redirected to the wrong website. Fortunately, most DNS servers have security features to protect them against such attacks. Still, they are not necessarily immune, since hackers continue to find ways to gain access to them. While pharming is not as common as phishing scams are, it can affect many more people at once. This is especially true if a large DNS server is modified. So, if you visit a certain website and it appears to be significantly different than what you expected, you may be the victim of pharming. Restart your computer to reset your DNS entries, run an antivirus program, then try connecting to the website again. If the website still looks strange, contact your ISP and let them know their DNS server may have been pharmed. |
| Phishing | A type of scam which attempts to steal an individual's identity and/or financial account credentials. Phishing attacks include sending spoof e-mails to lead the recipient to websites designed to trick the recipient into entering financial data such as credit card numbers, account usernames, passwords etc. |
| Phone Switch | These are generally large cabinets with groups of phone port cards plugged into them. On one end the cards connect to the phone company via T1 or larger line; on the other end they usually connect to a punch-down block on the wall, which is in turn connected to groups of ports at people’s desks. Thus, people can plug phones into these ports and be connected to the phone company. The phone switch manages the connections between you and the outside world. Many offices have their own dedicated switches that they can maintain and control (within certain guidelines). In residential areas the phone company controls the switches. |
| PHP | A general purpose (server side) scripting language for web development that can be embedded in HTML. PHP is a popular alternative to ASP and ASP.NET, because it is cross platform, free and open source. PHP is a recursive acronym for "PHP: Hypertext Preprocessor". |
| PHRASE | More than one KEYWORD, searched exactly as typed in (all words required, in the order specified). Enclosing keywords in "double quotation marks" forms a phrase in most search engines. Sometimes a phrase is called a "character string." |
| Phreak | A person who breaks into phone systems, generally to get free phone or voicemail service–thus the “ph” at the beginning of the term, similar to “phone.” It can be expanded to apply to anyone who breaks into systems to get free goods or services. |
| Physical Address | For Physical Address of a network card see MAC Address. |
| Pico | a text editor originally designed for composing e-mail for Pine |
| PIN | 1. Personal Identification Number. A general term used to refer to any number used to authenticate a person. For example a PIN number for bank withdrawals is used to authenticate the use of a cash-card, and the cash-card cannot be used without entering the correct PIN number. 2. Performance Improvement Network. A social network where members can share information and ideas to enable individuals, organisations or communities to improve their performance. 3. Prior Information Notice. A published notice providing an indication of future needs, which eventually may be manifest in an ITT. A Prior Information Notice is intended to provide interested parties with advanced warning of a possible ITT. |
| pincushioning | On computer screens, lines that should be straight don't always appear that way. Lines that look bowed or curved are evidence of a pincushion error. Such problems are common at the right and left edges of a displayed image, resulting in a screen that appears to be bowed inward at the centers (thus the source of the name). Better monitors include controls to help you compensate for this error. |
| Ping | 1. Ping is a widely available network utility for performing a simple network connectivity test between the current network location and a remote one. It works by generating an ICMP echo-request packet, and then listening for the reply from the remote end. A ping test is used to establish that communications can be successfully established between two computers on a TCP/IP network. Ping was originally named after the "ping" from sonar. The idea was later introduced that it stood for "Packet INternet Groper". |
| Ping of Death | An attack that sends an improperly large ICMP echo request packet (a "ping") with the intent of overflowing the input buffers of the destination machine and causing it to crash. |
| Ping Scan | A ping scan looks for machines that are responding to ICMP Echo Requests. |
| Ping Sweep | An attack that sends ICMP echo requests ("pings") to a range of IP addresses, with the goal of finding hosts that can be probed for vulnerabilities. |
| Pinging | Using ping to check basic network connectivity. |
| Pipeline | Computer processors can handle millions of instructions each second. Once one instruction is processed, the next one in line is processed, and so on. A pipeline allows multiple instructions to be processed at the same time. While one stage of an instruction is being processed, other instructions may be undergoing processing at a different stage. Without a pipeline, each instruction would have to wait for the previous one to finish before it could even be accessed. To understand the benefit of a pipeline, imagine that a car manufacturing plant had to wait for each car to be fully completed before starting on the next one. That would be horribly inefficient, right? It makes much more sense to work on many cars at once, completing them one stage at a time. This is what a pipeline in a computer allows. Pipelining, as it is called, often keeps around six instructions at once in the processor at different stages of processing. Pipelines can be used for the CPU as well as for accessing memory (DRAM). |
| pipeline burst cache | This type of secondary cache is an advanced type of SRAM installed on the motherboard to boost computer performance. Pipeline burst SRAM is commonplace now in motherboard market, where it replaced the older Sync Burst cache, which works less efficiently with fast processors. |
| Pipeline Burst Cache (Pipeburst Cache) | A form of L2 cache that uses pipelining to speed data access by being able to feed data to the CPU at the same time as it pulls data from memory. The burst mode also allows the cache to fetch additional data from main memory before the CPU requests it. This type of cache was used back in the Pentium days when L2 cache was separate from the processor. |
| Piracy | When someone installs and uses commercial software without paying for the program, it is called "pirating" the software. This name comes from the traditional meaning of the word "pirate," which is a sea-faring criminal that steals and loots belongings from others. But far from the stereotypical sea pirate, a software pirate can be anyone who owns a computer. Software piracy is committed by simply downloading or copying a program that a user has not paid for. Since computer programs are stored in a digital format, they are easy to copy and reproduce. For example, a game may be burned to a CD and transferred to the computer of an individual who has not paid for the program. Software programs can also be illegally downloaded from the Internet from unauthorized sources. Since pirating software does not require many resources, it has grown into a major problem for the computer industry. While it may seem like an innocuous act, pirating software is the same as stealing. Software companies often invest thousands or even millions of dollars into creating the programs they sell. The income from selling these programs is what allows companies to produce the software and to continue improving the programs we use. Just because it is possible to copy a software program does not mean it is OK. Installing a commercial program from an illegal copy is the same thing as walking out of a store with the program and not paying for it. While there are some programs that are free to use (such as shareware and freeware programs), it is important to pay for commercial software. You can avoid software piracy by only downloading software from authorized sources and making sure that you have valid software licenses for all the programs you use. Remember that paying for software programs supports the software industry, which is good for all of us! |
| Pixel | The term "pixel" is actually short for "Picture Element." These small little dots are what make up the images on computer displays, whether they are flat-screen (LCD) or tube (CRT) monitors. The screen is divided up into a matrix of thousands or even millions of pixels. Typically, you cannot see the individual pixels, because they are so small. This is a good thing, because most people prefer to look at smooth, clear images rather than blocky, "pixelated" ones. However, if you set your monitor to a low resolution, such as 640x480 and look closely at your screen, you will may be able to see the individual pixels. As you may have guessed, a resolution of 640x480 is comprised of a matrix of 640 by 480 pixels, or 307,200 in all. That's a lot of little dots. Each pixel can only be one color at a time. However, since they are so small, pixels often blend together to form various shades and blends of colors. The number of colors each pixel can be is determined by the number of bits used to represent it. For example, 8-bit color allows for 2 to the 8th, or 256 colors to be displayed. At this color depth, you may be able to see "graininess," or spotted colors when one color blends to another. However, at 16, 24, and 32-bit color depths, the color blending is smooth and, unless you have some kind of extra-sensory vision capability, you should not see any graininess. |
| PKI (Public Key Infrastructure) | The infrastructure needed to support public key encryption. It requires a certificate authority to issue and verify the public keys, a registration authority that verifies the identity of a person or organization before a key is issued, a certificate directory of the public keys, and a certificate management system. Public key encryption can be used to verify an identity or to encrypt data or messages. |
| Plain Text | Text documents come in to flavors - "rich text" and "plain text." Plain text, as you might have guessed, is rather plain. While it supports standard ASCII characters, including numbers, symbols, and spaces, it does not support any type of text formatting. Therefore you cannot use bold, italics, underlining, or different font sizes in a plain text document. Because plain text does not contain information about text sizes or styles, it is the most efficient way to store text. Plain text documents often take up less than half the size of rich text documents containing the same number of characters. You can use a basic text editor such as Windows Notepad to create a plain text document. If you want to copy text from a formatted document without copying the style, you can also use Notepad. Just copy the text from the original document, paste it into Notepad, then copy it again. The unformatted text will be copied from Notepad to your clipboard. The next time you paste the text, it will be pasted as plain text. |
| Plaintext | Ordinary readable text before being encrypted into ciphertext or after being decrypted. |
| Platform | A means of generically grouping like computers. Macintosh computers are a platform; so are PCs running Windows. It’s not very specific, and multi-platform support can mean many things. If someone says to you “this application supports multiple platforms,” ask that person which ones he or she is talking about. |
| Platter | One of the rigid disks inside a hard drive used to store information. Hard drives typically contain between one and 5 platters apiece, but can contain more. Platters have been historically made out of aluminum, and more recently glass. |
| Plesk | The Parallels® Plesk Panel (ex: Parallels Plesk Control Panel, Plesk Server Administrator, PSA) software package is a commercial web hosting automation program. Originally released under the U.S. company Plesk Inc. and designed in Novosibirsk, Russia, Plesk became an SWsoft product when SWsoft acquired Plesk Inc. in July 2003.[1] Parallels Plesk Panel is now shipped under Parallels, Inc. since Swsoft rebranded itself as Parallels (an existing namebrand in its portfolio) in January 2008.[2] At that time, Plesk was rebranded as Parallels Plesk Panel.[3] Overview Parallels Plesk Panel allows a server administrator to set up new websites, reseller accounts, e-mail accounts, and DNS entries through a web-based interface. The administrator can create client and site templates, which predetermine resource allocation parameters for the domains and/or clients. Parallels Plesk Panel for Linux/UNIX supports multiple POSIX platforms, including Debian, Fedora, FreeBSD, Red Hat Linux, SUSE and Ubuntu. Parallels Plesk Panel for Windows supports Windows Server 2003 and Windows Server 2008 operating systems. Parallels Plesk Panel installs custom versions of or manages versions of MySQL and PostgreSQL databases (Microsoft SQL Server and Microsoft SQL Server Desktop Engine under Windows), Apache Tomcat Java platform server, ColdFusion server, as well as CounterStrike and Battlefield 1942 game servers. Add-ons Parallels Plesk Panel has several software packs that are not part of the main Parallels Plesk Panel code base. These add-ons are designed to fully interact with Parallels Plesk Panel. These Parallels Plesk Panel software packs include functionality for billing, website building, and multiple server support. They include: Parallels Plesk Billing Parallels Plesk Sitebuilder Parallels Plesk Expand |
| Plug and Play | Technology where adapters can be automatically configured by the system without user intervention. This removes the need for a user to worry about IRQ and DMA settings. Plug and Play used to also be referred to as "Plug and Pray". This was when the technology was new and not always reliable. |
| Plug-in | A (usually small) piece of software that adds features to a larger piece of software. Common examples are plug-ins for the Netscape® browser and web server. Adobe Photoshop® also uses plug-ins. |
| PNG | Portable Network Graphics. A compressed loss-less image format. Image files saved using the PNG format are usually given a .png file extension. |
| Point to Point Tunneling Protocol (PPTP) | A remote access protocol that allows people to make a connection to easily connect to their local network through the Internet or some other large network. Conversations are kept private through encryption. See also Virtual Private Network. |
| Pointer | (1) In programming, think of a pointer as an address. The address can point to just about anything, including another pointer. Ultimately, if you follow the trail of pointers you’ll probably find some data–pointers are most often used to point to data. The purpose of pointers is so that when you are programming you can pass around a small address that points to some data, instead of passing the actual data around. (2) Pointers can also refer to the icon on the screen that you move around with a mouse or other pointing device. In a GUI environment you need a pointer to point to things so that you can select them. |
| Poison Reverse | Split horizon with poisoned reverse (more simply, poison reverse) does include such routes in updates, but sets their metrics to infinity. In effect, advertising the fact that there routes are not reachable. |
| Policy | 1. An adopted plan or course of action. For example, a company may have a written policy on the disposal of equipment. 2. A set of rules that control some aspect of a system's behaviour, often enforced automatically by the system. For example a password policy would specify things like minimum password length and password history. 3. A contract of insurance. This is a document setting out what is and is not covered under an insurance contract and any limitations and responsibilities of the insurance company or the policy holder. |
| Poll (v. to poll) | When one computer, device, or program asks for an answer to a query from another computer or device over a period of time until a condition is met. For example, a program may poll an IP address to see when it is available. |
| Polyinstantiation | Polyinstantiation is the ability of a database to maintain multiple records with the same key. It is used to prevent inference attacks. |
| Polymorphism | Polymorphism is the process by which malicious software changes its underlying code to avoid detection. |
| POP | Post Office Protocol. A protocol for accessing e-mail, allowing e-mails to be downloaded form a server, stored locally and therefore available for off-line reading. cf POP3. |
| Pop-Up | The term "pop-up" has two computer-related meanings. One refers to a window and the other is a type of menu. 1. Pop-Up Window A pop-up window is a type of window that opens without the user selecting "New Window" from a program's File menu. Pop-up windows are often generated by websites that include pop-up advertisements. These ads are produced with JavaScript code that is inserted into the HTML of a Web page. They typically appear when a user visits a page or closes a window. Some pop-up ads show up in front of the main window, while others show up behind the main browser window. Ads that appear behind open windows are also called "pop-under" ads. Regardless of where pop-up advertisements appear on your screen, they can be pretty annoying. Fortunately, browser developers have realized this and most Web browsers now include an option to block pop-up windows. If you are noticing pop-up windows appear on your computer when your browser is not open, you may have an adware program running on your computer. The best solution to this problem is to run an anti-spyware program that will locate and remove the malware from your system. 2. Pop-Up Menu A pop-up menu is a type of menu that pops up on the screen when the user right-clicks a certain object or area. It can be also called a contextual menu since the menu options are relevant to where the user right-clicked on the screen. Pop-up menus provide quick access to common program functions and are used by most operating systems and applications. |
| POP3 | Post Office Protocol version 3. Used for accessing email, see POP for details. The version of POP adopted is version 3, hence the name POP3. |
| Port Replicator | A device that is used to provide laptops–with limited ports and expansion options built-in–with a larger amount of ports and expandability. Most port replicators are proprietary devices that work with one particular model of laptop and add extra ports such as additional USB and PS/2 ports and sound line-in and line-out ports. |
| Port Scan | A port scan is a series of messages sent by someone attempting to break into a computer to learn which computer network services, each associated with a "well-known" port number, the computer provides. Port scanning, a favorite approach of computer cracker, gives the assailant an idea where to probe for weaknesses. Essentially, a port scan consists of sending a message to each port, one at a time. The kind of response received indicates whether the port is used and can therefore be probed for weakness. |
| Portable Document Format (PDF) | A format developed by Adobe. Adobe makes a freeware Adobe Acrobat Reader program that is available for a variety of platforms. Thus, using a variety of operating systems, you can download and read a PDF document with very little hassle. In addition, the PDF format strives for easy printing, viewing, and compact storage. On PCs .pdf is the file extension for this type of file. |
| Portal | While this term can also refer to a matterless vortex used to travel between different dimensions, an Internet portal is a Web site that acts as a starting point for browsing the Web. Portals typically include search engines and large directories of websites. Some popular portals are Yahoo, Excite, Lycos, Netscape, AltaVista, MSN, and AOL.com. There are also many smaller portals, known as "niche portals," for specific interests. These sites include C|net (for computers and technology), Fool.com (for investors), and Garden.com (for gardeners). Most large portals have millions of Web pages indexed for visitors to search though. They also have large directories of Web sites, which are categorized by topic. Though the primary purpose of a portal is to find other sites for you, many now include a lot of information within their own sites. |
| Portal (Web portal) | A term coined to describe the large search engine sites, such as Yahoo! and Lycos, that have branched off to offer a wide variety of services. The idea is that a Web user would peer at the Web by using only one website: the portal. For example, you go to a portal to do searches, get stock quotes, buy things, etc. It would be your everything site. Each portal site wants to offer one of each type of service so that a user never has to leave the site. |
| POSIX (Portable Operating System Interface) | A set of operating system interface standards based on UNIX. The standards were developed so that programs could be written more easily that would work on multiple versions of UNIX from different manufacturers. |
| Possession | Possession is the holding, control, and ability to use information. |
| POST | 1. Power On Self Test. A set of tests performed by a computer's BIOS straight after power up. 2. The act of sending a message to a newsgroup, where others can view and respond to it. The term Post can also be used to refer to that message posted to a newsgroup. 3. To send a message. This usage originates from traditional postal services (snail-mail), but applied to applications, processes and threads. A message can be said to be posted to another process (thread or application). |
| Post Office Protocol 3 (POP3) | A standard for client/server transmission of e-mail. An e-mail server holds the e-mail, and you use a POP3 client to fetch the mail from a server. IMAP is a newer e-mail client/server protocol with more options. |
| PostScript | A standard language for telling printers how to print text and graphics. Most Macs use PostScript to print, while PCs normally default to PCL. |
| POTS (Plain Old Telephone Service) | The regular telephone service that people have in their homes. Newer technologies such as ISDN, digital phones, cellular phones, or DSL are not referred to as POTS. |
| Power Cycle | While the phrase "power cycle" appears to be a noun, it is actually more commonly used as a verb. In simple terms, to power cycle a device means to turn it off and turn it back on again. For example, the user manual of a router may ask you to power cycle the router if it stops responding. This may mean switching the power to OFF and then ON again or may require physically unplugging the device and then plugging it back in again. Power cycling is often synonymous with resetting a device. As we all know, computer equipment can be rather finicky at times. A device that was working fine ten minutes ago may begin acting strangely or may not be responding at all. Often the low-tech solution of simply turning off the device and turning it back on again will fix the problem. This is because information stored in the device's RAM may have gotten corrupted and caused the device to hang up or stall on a certain instruction. Power cycling the device erases the RAM and allows it to boot up with fresh information. Typically it is a good idea to wait 5 to 10 seconds before turning the device back on to make sure it has chance to fully reset. Of course, if you need to power cycle your computer, you should save any work you currently have open, since it will be erased from the RAM once the system is restarted. |
| Power PC | A line of microprocessors developed by Motorola, Apple, and IBM; this chip is used in Power Macintoshes. |
| Power Supply | A device attached to the case that converts 120 AC (in the U.S.) to DC at voltages that a computer needs to run. They come rated by wattage. |
| PowerNow! | AMD’s power saving technology used in some of its mobile processors. It allows the OS and power management to tune down the speed of the processor in order to conserve power. |
| PowerStep | An Apple/Motorola power management technology that allows PowerPC processors to be tuned down in speed when not plugged in so that power can be conserved. |
| PPM | Stands for "Pages Per Minute." PPM is used to measure the printing speed of both inkjet and laser printers. Most printers include a PPM rating for both black and color documents. These speed measurements are typically listed in the printer's technical specifications. While a higher pages per minute rating does indicate a faster printing speed, this measurement can be misleading. This is because manufacturers measure the maximum PPM in the fastest printing mode, a.k.a. "economy mode," which is also the lowest quality. When printing in regular mode, the speed may be twice as slow. When printing in fine or high-quality mode, the speed will likely be reduced even further. Furthermore, a printer's maximum PPM speed is measured using basic text pages, with no graphics, lines, or other objects. Therefore, if you have a text document that includes a picture, the page could take several times longer to print than a plain text document. If you are going to be printing a lot of color photos, make sure to check the printer's photo printing speed, which is often significantly slower than the printer's maximum PPM. Finally, the PPM measurement does not take into account how long it takes the printer to warm up and begin printing. Therefore, if you are only printing one or two pages, the warm up time may be longer than the actual time it takes to print the document. In summary, PPM gives a general idea of how fast a printer is. But since there are several other variables involved that determine a printer's speed, PPM does not always accurately reflect a printer's speed. Therefore, when choosing a printer, it may be helpful to read some reviews about the printer you are interested in. The reviews may give you a better idea of the printer's real-world speed an quality than the numbers on the box do. NOTE: PPM can also be used to measure a scanner's scanning speed. This measurement is particularly important for scanners that use an automatic document feeder ADF, which allows multiple documents to be scanned consecutively. |
| PPP | tands for "Point to Point Protocol." It is the Internet standard for dial-up modem connections. PPP is a set of rules that defines how your modem exchanges packets of data with other systems on the Internet. If you connect to your ISP with a dial-up modem, you are most likely using PPP. |
| Preamble | A preamble is a signal used in network communications to synchronize the transmission timing between two or more systems. Proper timing ensures that all systems are interpreting the start of the information transfer correctly. A preamble defines a specific series of transmission pulses that is understood by communicating systems to mean "someone is about to transmit data". This ensures that systems receiving the information correctly interpret when the data transmission starts. The actual pulses used as a preamble vary depending on the network communication technology in use. |
| Precision | Precision is how well you define a value. For example, if the value you are representing is 4.321 and you say it’s 4.3, you are precise to two places. Numerically, precision is the amount of decimal digits that you are capable of measuring. |
| Preemptive Multitasking | Multitasking operating system strategy in which the operating system scheduler controls which process will run at a given time and for how long before control passes to another process. cf Cooperative Multitasking. |
| Pretty Good Privacy (PGP) | A freeware program that secures e-mail messages by encrypting and/or adding a digital signature to them. There are also commercial versions of PGP available that encrypt data and offer a wider variety of options. |
| primary cache | By caching data in fast, pricey memory, you speed up your system performance. Primary cache is fast, usually integrated into the CPU chip, and not very large (typically 16K). While it's useful for storing some instructions, it usually relies on a secondary (L2) cache for an all-around boost of system performance. |
| Primary Domain Controller (PDC) | In Windows NT and 2000 networking, this machine is the main machine that responds to security authentication requests, such as logging in, within its domain. The PDC may be backed by one or more backup domain controllers that can also handle security authentication. |
| Primary Key | A primary key is a unique identifier for a database record. When a table is created, one of the fields is typically assigned as the primary key. While the primary key is often a number, it may also be a text field or other data type. For example, if a database contains definitions of computer terms, it would make sense that each term is only listed once in the database. By defining the "Term" field as the primary key, it would ensure that no term is listed more than once in the database. While a table's primary key is usually assigned to a specific field, it can also be comprised of multiple values. For example, a database of news articles might use both the title and date fields to uniquely identify each entry. By combining the "Title" and "Date" fields as the primary key, it would ensure no entries have the same title on the same day. If multiple fields in a table cannot have duplicate values, most database management system (DBMS) also allow fields to be defined as "Unique." This is similar to setting a field as the primary key, but is not exactly the same thing. The primary key also acts as a pointer to the record and provides a simple way for the DBMS to search, sort, and access the records. It also helps relate records across multiple tables. Therefore, while multiple fields within a table can be defined as "Unique," each table can only have one primary key. The primary key field must also be defined for each record and not set to null. After all, a undefined identifier is not very useful. |
| Primary partition | A partition that is bootable. You cannot have more than four primary partitions per drive. |
| Print Screen | This button is intended to print whatever is on your screen. If you are using DOS, or you are in your BIOS and have a printer set up, the Print Screen button should do just that. In Windows OSes,hitting the Print Screen button will copy your current desktop so that you can paste it into a graphics program, or a program that will support graphics, such as many word processors today. Additionally, hitting Alt-Print Screen will copy just the window that is active at the time. |
| Print Server | The interface between a printer and a network that allows network clients to connect to the printer and send their print jobs to it. Print servers can be computers, separate hardware devices, or even hardware that resides inside of the printer itself. |
| Printer | Any device that makes an impression on media, usually paper, and is connected to a computer. The invention of the computer with printer has almost made the typewriter obsolete. The simplest printers are located in cash registers printing out receipts, while more advanced printers are capable of magazine-quality photo images. Printers come in several types, including daisy-wheel, dot matrix, inkjet, laser, and dye sublimation. |
| Printer Control Language (PCL) | A set of commands used to communicate with Hewlett Packard printers. Each printer company has its own language, but PCL has become a generic term to describe these languages. See also Postscript. |
| Private Branch Exchange (PBX) | A private phone switch used within a company that allows inter-company phone calls without using outside lines. It also connects to one or more outside POTS lines, which are often partitioned off into outgoing lines, incoming lines, or lines that can be used for both purposes. PBXs today use digital connections for inter-company calls, thus you must use digital phones as opposed to standard analog phones (and modems). A PBX is typically a large and costly piece of machinery maintained and/or supported by the company that sold the PBX. There are various options that can be added onto PBXs for call reporting, call management, and voicemail. |
| Processor | This little chip is the heart of a computer. Also referred to as the "microprocessor," the processor does all the computations such as adding, subtracting, multiplying, and dividing. In PCs, the most popular microprocessor used is the Intel Pentium chip, whereas Macintosh computers use the PowerPC chip (developed by Motorola, IBM, and Apple). The speed of a computer's processor is measured in megahertz, or cycles per second. But higher megahertz doesn't always mean better performance. Though a 600-MHz chip has a clock speed that is twice as fast as a 300-Mhz chip, it doesn't mean that the computer with the 600-Mhz chip will run twice as fast. This is because the speed of a computer is also influenced by other factors, such as the efficiency of the processor, the bus architecture, the amount of memory available, and the software that is running on the computer. Some processors can complete more operations per clock cycle than other processors, making them more efficient than other processors with higher clock speeds. This is why the PowerPC chip is typically faster than Pentium chips at that are clocked at higher megahertz. |
| Program | rogram is a common computer term that can be used as both a noun and a verb. A program (noun) is executable software that runs on a computer. It is similar to a script, but is often much larger in size and does not require a scripting engine to run. Instead, a program consists of compiled code that can run directly from the computer's operating system. Examples of programs include Web browsers, word processors, e-mail clients, video games, and system utilities. These programs are often called applications, which can be used synonymously with "software programs." On Windows, programs typically have an .EXE file extension, while Macintosh programs have an .APP extension. When "program" is used as verb, it means to create a software program. For example, programmers create programs by writing code that instructs the computer what to do. The functions and commands written by the programmer are collectively referred to as source code. When the code is finished, the source code file or files are compiled into an executable program. |
| Program Infector | A program infector is a piece of malware that attaches itself to existing program files. |
| Program Policy | A program policy is a high-level policy that sets the overall tone of an organization's security approach. |
| Progressive Scan | Video signals are generated using horizontal lines. An interlaced picture draws every other line and alternates between drawing odd lines and even lines. A progressive scan picture draws every line in sequence. Therefore, a progressive scan video signal sends twice as much data than an interlaced signal each time it draws an image on the screen. Before DVDs and HDTV became popular, interlaced video was the norm for television. Standard definition broadcasts were interlaced, since it was a more efficient way to send video data. Since the human eye has a hard time detecting video interlacing, an interlaced signal that refreshes at 60 Hz (times per second) is easier on the eyes and produces less flicker than a progressive scan signal that refreshes at 30 Hz. Still, if a progressive scan and interlaced image are both projected at 60 Hz, the progressive scan image will usually appear slightly smoother. Video that contains fast motion makes this difference more noticeable. For this reason, the DVD and HDTV standards were developed to support progressive scan video signals. When you see video formats described as 480p or 720p, the number indicates how many horizontal lines of resolution the video signal uses, while the "p" indicates it is a progressive scan signal. Similarly, the 1080i format contains 1080 lines of resolution, but is interlaced. Both 720p and 1080i are used by HDTV. |
| PROM (Programmable Read Only Memory) | This is a memory device. Once data is written to a PROM it is there forever, unlike with an EPROM. A PROM is also a curious high school ritual involving strangely colored dresses, tuxedos, and sometimes limousines, unconsciously mirroring the wedding rituals most of its participants will undergo at some point in the following 10-15 years. PROMs leave some traumatized and others gleeful, but everyone agrees the post-PROM activities are always better than the PROM itself. |
| Promiscuous Mode | Although it sounds naughty, as it relates to networking promiscuous mode implies that a network card is able to recognize all network traffic with which it comes in contact. Generally you need a promiscuous mode card using a promiscuous mode driver to run any kind of network packet-filtering tool effectively. |
| Proprietary Information | Proprietary information is that information unique to a company and its ability to compete, such as customer lists, technical data, product costs, and trade secrets. |
| protected mode | An operating mode of x86 chips that lets the PC access the largest possible amount of memory. In protected mode, different parts of memory are assigned to different programs. This way, memory is "protected" in the sense that only the assigned program can access it. The phrase is often used to describe device drivers that operate in this mode. Windows and OS/2 run primarily in protected mode, but can switch between the use of protected-mode and real-mode applications. |
| Protocol | A protocol is an agreed set of rules for the communication of information between two or more devices. Whilst the list of protocols is probably near endless, the following are examples of common protocols: HTTP - Hypertext Transport Protocol, used for the transfer of web pages. NNTP - Network News Transport Protocol, used for newsgroups. SMTP - Simple Mail Transfer Protocol, used for sending emails. FTP - File Transfer Protocol, used for transferring files. |
| Protocol Stacks (OSI) | A set of network protocol layers that work together. |
| Proxy | A system (software or hardware) that acts on behalf of another to perform some service. A proxy acts as an interface, hiding the system that ultimately performs the service. Whilst this is not an exhaustive list, a proxy is typically used to provide for any of the following: to bridge separate networks for performance By caching requests - if two or more users are using a cache then there are situations where a single centralised cache will outperform separate caches local to the users. to provide centralised logging of requests to provide anonymous access The user that initiated the request hides behind the proxy and only the proxy is visible to the server that ultimately responds to the request. An HTTP Proxy is a typical example of a proxy. |
| Proxy Server | 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. |
| PS/2 | This is a PC made by IBM that can run OS/2 and DB/2. Of course, it can run anything a normal PC can run, but it’s just a nifty IBM naming convention that caught on. |
| PS/2 port | A standard serial port connector used to plug mice and keyboards into PCs. It’s got 6 pins and is small and round, compared to the larger 9- and 25-pin serial connectors still found on some PCs. |
| PST | Pacific Standard Time. Abbreviated name for the time zone used on the West coast of America. PST = UTC - 8 hours. |
| PSTN | Public Switched Telephone Network. |
| PSU | Power Supply Unit. An electrical device that converts from the mains AC electrical supply into DC voltage (or voltages) required by an electronic device. A PSU may be internal to the device or external. Typically the larger the device to be powered the more likely that the PSU is internal. For example the PSU in a computer is internal to the computer and may be removed and replaced as a unit, whereas the PSU for an external disk drive is normally a completely separate unit. |
| public domain | public domain Of all the kinds of software or information you can download, public domain has the fewest strings attached. With shareware, you're expected to pay a fee. With freeware, you may face other restrictions, and there's still a copyright attached. With public domain downloads (also called downloads in the pubic domain), there are no copyright restrictions whatsoever. See also: shareware, freeware |
| Public Key | The publicly-disclosed component of a pair of cryptographic keys used for asymmetric cryptography. |
| Public Key Encryption | The popular synonym for "asymmetric cryptography". |
| Public Key Infrastructure (PKI) | A PKI (public key infrastructure) enables users of a basically unsecured public network such as the Internet to securely and privately exchange data and money through the use of a public and a private cryptographic key pair that is obtained and shared through a trusted authority. The public key infrastructure provides for a digital certificate that can identify an individual or an organization and directory services that can store and, when necessary, revoke the certificates. |
| public method | In object-oriented languages such as Smalltalk or Java, public is one of several modifiers you use to control access to a method. A public method is available to any class in any file. If you use no modifier, only classes declared in the same file have access to the method. See also: Java, object |
| Public-Key Forward Secrecy (PFS) | For a key agreement protocol based on asymmetric cryptography, the property that ensures that a session key derived from a set of long-term public and private keys will not be compromised if one of the private keys is compromised in the future. |
| pull | Frequently used to describe data sent over the Internet; the act of requesting data from another computer. Example: using your web browser to access a specific page. Contrast to "push" technology when data is sent to you without a specific request being made. |
| Pull Down | 1. To download data or a file from a remote server, typically a file. 2. To remove a file from a public (or publicly accessible) site. |
| pulldown menu | A list of options that "pulls down" when you select a menu at the top of a window. For example, the File menu in most programs is a pulldown menu that reveals commands such as open, new, and save. |
| Purge (v. to purge) | A synonym for deleting something, usually in such a way that it cannot be easily recovered. It is used in several contexts, including the deletion of print jobs from a print queue and the final deletion of files from the NetWare operating system. You can purge print jobs to clean out a print queue that is not behaving, or purge files in NetWare to free up space and fully delete files that were specified for deletion. |
| Push | Push refers to a system in which data is "pushed" to a user's device rather than "pulled" by the user. In other words, the data transfer is initiated by the server rather than the client. Push technology, which is also called "server push," can be used to send news data, stock updates, and other information from the Internet to a user's computer. It is also used to send text messages via SMS to people's cell phones. Push e-mail allows users to receive e-mail messages without having to check their e-mail manually. This means new messages appear on the client's device as soon as they are received by the server. However, in order to receive pushed messages, both the mail server and the user's e-mail client must support push technology. While most information is still "pulled" from the Internet, more kinds of data can now be pushed to users' systems. With push technology, people no longer need to constantly check news sites, e-mail, or other data sources to see if they have been updated. The result is a more efficient means of receiving information. |
| PWB | Printed Wiring Board. Same as PCB, but in Japan is normally referred to as PWB to avoid confusion with "Polychlorinated Biphenyls (PCBs)" which is a poison. |
| PXE | Pre-boot Execution Environment. An Intel standard for booting across a LAN. A workstation boots into the PXE where it can respond to management configuration before loading the operating system. |
| Python | A web scripting language. Python is an open source object oriented programming language. |
