packet
A group of consecutive characters transmitted from one computer to another over a network.
parallel
The transmission of several bits at the same time over separate wires.
parity bit
A very basic method of error-correcting code that uses the value of an extra bit sent at the end of a data string. The bit must have a set value based on an algorithm to verify that the data at the receiving end is correct.
path
The address to a file. The path consists of the drive name, the location of the file in the directory structure, and the filename. Example: C:\Mystuff\Myfile.doc.
peer-to-peer network
A network in which each connected computer acts as either a server or a client depending on the users' needs. Each user or workstation establishes its own security and determines which resources are available to other users. These networks are limited in size, usually 15 to 20 workstations.
peripheral
An external device connected to a computer such as a printer, scanner, modem, or joystick.
persistence
The amount of time a pixel stays visible on a monitor screen, which is a factor of the decay of activity in the phosphor coating.
PGA (Professional Graphics Adapter)
An adapter that was originally marketed to the engineering and scientific communities. It was expensive and required three ISA slots when fully configured. This system offered 3-D rotation and 60 frames per second animation. It used a 15-pin, three-row, female DB-type connector. It gained limited use in CAD environments, but was quickly replaced by better mass-market solutions.
ping
To send a data packet from your computer to a site or other user to test the connection's performance. If the other site is down, the ping fails and if the site is up, the packet bounces back ("pongs").
pixel
Short for "picture element." One of the dots that make up a graphical image.
plotter
Similar to a printer, but uses pen(s) to draw an image. Used most often with graphics and drawing programs.
port
Specific channel used by a network service. For example, Gopher often uses port 70, while some Web sites use port 80.
power
The strength or force actually put forth by electricity. Electrical power is measured in watts, which is measured by multiplying voltage by current.
power supply
Takes alternating current (AC) power from a local source (a wall outlet) and converts it to direct current (DC) for on-board electronics use.
PPP (Point-to-Point Protocol)
A direct connection from a computer to the Internet, over modem and telephone lines.
PPTP (Point-to-Point Tunneling Protocol)
The latest version of PPP. It allows users to create a virtual network over the Internet.
printer
A peripheral device that transfers computer output to paper or other form of hard copy.
prompt
The command prompt-a user interface provided by COMMAND.COM to signal to the user that the computer is ready to receive input (for example, C:\> or A:\>).
protected mode
A mode introduced with 80286 processors that used an operating system like OS/2 or Windows to allow creation of "virtual machines." These provided the functionality of a standard computer in real mode but allowed multiple tasks to take place at the same time. The term refers to the fact that processor, memory, and other hardware are "protected" from the software applications by the operating system, which allocates the memory and processor time.
protocol
A set of rules that govern the transfer of information. The format used to upload or download files to allow two different computers to communicate in a standard format.