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P
Packet
| Parallel Port
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Parse |
Partition
| PCI
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PCMCIA
| PDA
| PDF |
Perl |
PHP | PIM | Ping | Pixel |
Plug-in
| PNG | Port | Portal
| PPGA |
PPP | Protocol
|
Proxy Server
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.
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Parallel Port
This interface is found on the back of a PC 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.
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Parse
No, this is not a typo of the word "sparse." To parse text means to break it up
into smaller parts. The term is commonly used in computer science to refer to
reading programming code. For example, after a program is written, whether it be
in C++, Java, or any other language, the code needs to be parsed by the complier
in order to be compiled. Web scripts, written in scripting languages such as
Perl or PHP, need to be parsed on the Web server so that they can output the
correct HTML to a user's browser.
Parsing can also mean breaking up ordinary text. For example, search engines
typically parse search phrases entered by users so that they can more accurately
search for each word. Some programs can parse text documents and extract certain
information like names or addresses. Spreadsheet programs can turn formatted
documents into tables with rows and columns by parsing the text. The uses of
parsing are clearly not sparse.
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Partition
A partition is a section of a hard drive. When you format a hard drive, you can
usually choose the number of partitions you want. The computer will recognize
each partition as a separate drive, 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
drive. On larger drives, the cluster or block size (which is the minimum amount
of space a file can take up), is larger than on small drives. 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.
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PCI
Stands for "Peripheral Component Interconnect." It is a hardware bus designed by
Intel and used in both PCs and Macs. Most add-on cards such as SCSI, Firewire,
and USB controllers, use a PCI connection. Some graphics cards use PCI, but most
new graphics cards connect to the AGP slot. PCI slots are found in the back of
your computer and are about 3.5" long and about 0.5" high. So before you go buy
that Firewire expansion card, make sure you have at least one PCI slot
available.
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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.
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PDA
Stands for "Personal Digital Assistant." These are the little electronic devices
you see people jotting stuff down on in public. Usually, when you see someone
with a PDA, they will be holding it out far front of them for everyone to see.
Fortunately, as PDAs become more common, more people will have them and we won't
have to deal with the people who make sure everyone else sees that they have
one.
The first PDA, called the Newton, was created by Apple in 1973. Since then,
numerous other companies have jumped on the bandwagon and have added many new
designs and options to the PDA market. The Palm Pilot, Handspring Visor, HP
Jordana, Compaq Aero, Sharp Mobilon, and Sony Clié are all common PDAs.
Ironically, Apple's Newton was discontinued when the company was having
financial difficulties in 1998. Today's PDAs allow you to organize your
schedule, take notes, do math calculations, play games, write memos, and even
surf the Internet and send e-mail. They are cool things to have, but if you
decide to get one, please do us all a favor and don't show it off in public.
PDA also stands for "Public Display of Affection," and though this term is all
too relevant at college campuses, it has nothing to do with this definition.
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PDF
Stands for "Portable Document Format." It is a multi-platform file format
developed by Adobe Systems. A PDF file captures document text, images, and most
impressively, the formatting of documents from a variety of applications. You
can send a PDF document over the Internet to your friend and it will look the
same way on his screen as it looks on yours. PDF documents also print out the
same way they look on your monitor.
To view a PDF file, you need Adobe Acrobat Reader, a free application
distributed by Adobe Systems. There is also an Acrobat Plug-in for Web browsers
that enables PDF files to be viewed from within your browser.
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Perl
Perl actually stands for "Practical Extraction and Report Language," but you
don't really need to know that unless you want to impress your nerd friends.
Perl is a scripting language which uses a syntax similar to C/C++. It is
commonly used by Web programmers to create scripts for Web servers. Perl is
especially good at parsing text, so programmers often use it for reading and
searching through text files. As a regular computer user, you won't get to see
Perl in action, since it does most of its work "behind the scenes." Perl scripts
are run on the server computer before any information is sent to your Web
browser. Oh well, the code looks like hieroglyphics to most people anyway.
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PHP
PHP is an HTML-embedded Web scripting language. This means PHP code can be
inserted into the HTML of a Web page. When a PHP page is accessed, the PHP code
is read or "parsed" by the server the page resides on. The output from the PHP
functions on the page are typically returned as HTML code, which can be read by
the browser. Because the PHP code is transformed into HTML before the page is
loaded, users cannot view the PHP code on a page. This make PHP pages secure
enough to access databases and other secure information.
A lot of the syntax of PHP is borrowed from other languages such as C, Java and
Perl. However, PHP has a number of unique features and specific functions as
well. The goal of the language is to allow Web developers to write dynamically
generated pages quickly and easily. PHP is also great for creating
database-driven Web sites.
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PIM
Stands for "Personal Information Manager." A PIM is a software application that
serves as a planner, notebook, and address book all in one. It can also include
things like a calculator, clock , and photo album. PIMs are especially popular
for PDAs (Personal Digital Assistants), since this is why most people have them.
However, for those of us who don't have all the latest portable gadgets, PIM
programs are also developed for desktop computers.
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Ping
This term refers to a golf equipment brand, as well as the sound made by
striking your glass with a spoon at the dinner table. However, it also has a
computer-related meaning. A ping is a test to see if a system on the Internet is
working. "Pinging" a server tests and records the response time of the server.
Pinging multiple computers can be helpful in finding Internet bottlenecks, so
that data transfer paths can be rerouted a more efficient way. A good way to
make sure you do not get disconnected from your dial-up ISP for being idle is to
send a ping every 5 minutes or so. There are a number of shareware Ping programs
that will do this for you.
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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.
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Plug-in
Though software plug-ins might not make your room smell as nice as the scented
ones you stick in an outlet, they are still useful. A software plug-in is an
add-on for a program that adds functionality to it. For example, a Photoshop
plug-in (such as Eye Candy) may add extra filters that you can use to manipulate
images. A browser plug-in (such as Macromedia Flash or Apple QuickTime) allows
you to play certain multimedia files within your Web browser. VST plug-ins add
effects for audio recording and sequencing programs such as Cubase and Logic
Audio.
Most graphics and audio programs today support plug-ins since they are a
convenient way to expand the capabilities of the program. Though some plug-ins
may be shipped with the program, most are developed by third-parties and are
sold separately. Because companies that make browser plug-ins are often
competing for a standard (such as Flash and QuickTime), these plug-ins are
usually available as free downloads from the Internet.
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PNG
Stands for "Portable Network Graphic." This format was designed as an
alternative to the GIF format (which has been plagued by copyright issues). Like
GIFs, PNG files are lossless, meaning they don't lose any detail when they are
compressed. They support up to 48-bit color or 16-bit grayscale and typically
compress about 5% to 25% better than GIF files. However, they do not support
animations like GIFs do. A format similar to PNG, called MNG, is currently under
development, and will support animations.
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Port
As if computer terms weren't hard enough to understand, there are three
different meanings of the word "port."
1. An Internet port. This is a number that indicates what kind of
protocol a server on the Internet is using. For example, Web servers typically
are listed on port 80. Web browsers use this port by default when accessing Web
pages, but you can also specify what port you would like to use in the URL like
this: http://www.excite.com:80. FTP uses port 21, e-mail uses port 25, and game
servers, like a Quake server or Blizzard.net use various other ports. It is good
to know what a port is, but you seldom have to specify it manually, so don't
worry if this is new to you.
2. A hardware port. This refers to any one of the ports that are on the
back of a computer where devices can be hooked up (like a keyboard, mouse,
printer, digital camera, etc). Some common ports found on today's computers are
USB, Firewire, and Ethernet.
3. The verb, "port." This refers to the editing of a software program's
code so that it can run on another platform. For example, to get Final Fantasy
VII to run on a PC, programmers needed to port it to the PC from the
Playstation. Popular Windows games are often ported to the Macintosh as well.
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Portal
While this term often refers to a matterless vortex used to travel between
different dimensions, an Internet portal is a Web site that acts as a starting
point with links to many other sites. Some of the largest portals include 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 a large directory 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.
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PPGA
Stands for "Plastic Pin Grid Array" (not the Pretty People Golfer's
Association). PPGA is a type of processor design or "form factor" used by the
Intel Celeron processor. The design allows the heat generated by the chip to
dissipate more quickly. This enables the processor to use more transistors and
run at higher speeds without burning a hole in the side of your computer. If
you'd like to know more about PPGA, check out Intel's own documentation.
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PPP
Stands for "Point to Point Protocol." This 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're most likely using PPP.
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Protocol
When computers communicate with each other, there needs to be a common set of
rules and instructions that each computer follows. A specific set of
communication rules is called a protocol. Because of the many ways computers can
communicate with each other, there are many different protocols -- too many for
the average person to remember. Some examples of these different protocols
include PPP, TCP/IP, SLIP, HTTP, and FTP. Can you guess what the last "P" in
each acronym stands for? If you guessed "protocol," send yourself a
congratulations e-mail.
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Proxy Server
Most large businesses, organizations, and universities these days use a proxy
server. This is a server that all computers on the local network have to go
through before accessing information on the Internet. By using a proxy server,
an organization can improve the network performance and filter what users
connected to the network can access.
A proxy server improves Internet access speeds from a network primarily by using
a caching system. Caching saves recently viewed Web sites, images, and files on
a local hard drive so that they don't have to be downloaded from the Web again.
While your Web browser might save recently viewed items on your computer, a
proxy server caches everything accessed from the network. That means if Bob
views a news story at cnn.com at 1:00 and Jill views the same page at 1:03,
she'll most likely get the page straight from the proxy server's cache. Though
this means super-fast access to Web pages, it also means users might not be
seeing the latest update of each Web page.
The other main purpose a proxy server is to filter what is allowed into the
network. While HTTP, FTP, and Secure protocols can all be filtered by a proxy
server, HTTP is the most common. The proxy server can limit what Web sites users
on the network can access. Many organizations choose to block access to sites
with objectionable material such as hacking information and pornography, but
other sites can be filtered as well. If an employer notices workers are spending
too much time at sites like eBay or Quicken.com, those sites can be blocked by
the proxy server as well.
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