P

packed-pixel frame buffer

A portion of the display memory that holds the contents of a single screen image with screen bits stored in a single plane and with each pixel on the screen having a set of two or more corresponding bits that define the pixel color.

PAL format

Phase Alternation Line format. The European video standard, except for France. See also NTSC and SECAM.

PC 97

The 1997–98 requirements for PC system and peripheral design for the "Designed for Microsoft Windows" logo, as defined in PC 97 Hardware Design Guide.

PC 98

The 1998–99 requirements for PC system and peripheral design for the "Designed for Microsoft Windows" logo, as defined in PC 98 Checklist, which is an addendum to PC 97 Hardware Design Guide.

PC Card

A trademark of PCMCIA. A removable device that is designed to be plugged into a PCMCIA slot and used as a memory-related peripheral.

PCI

Peripheral Component Interconnect. A high-performance, 32-bit or 64-bit bus designed to be used with devices that have high bandwidth requirements, such as the display subsystem.

PCM

Pulse code modulation. A method of encoding information in a signal by varying the amplitude of pulses. The most common method of encoding an analog signal into a digital bit stream.

PCMCIA

Personal Computer Memory Card International Association. Sometimes used to refer to a controller for a type of expansion card documented in the PCMCIA standards.

PIC

Programmable interrupt controller

pin

A set of filter-defined properties in kernel streaming and ActiveMovie that specify a connection endpoint. For example, audio input can be described by a pin on a filter.

pixels

An abbreviation for picture element. The minimum raster display element, represented as a point, with a specified color or intensity level. One way to measure picture resolution is by the number of pixels used to create images.

planar

See system board.

Plug and Play (PnP)

A design philosophy and set of specifications that describe hardware and software changes to the PC and its peripherals that automatically identify and arbitrate resource requirements among all devices and buses on the system. Plug and Play specifies a set of API elements that are used in addition to, not in place of, existing driver architectures.

Plug and Play BIOS

A BIOS with responsibility for configuring Plug and Play cards and system-board devices during system power up. Provides runtime configuration services for system board devices after startup. See also ACPI.

port

A connection or socket used to connect a device—such as a printer, monitor, or modem— to the computer. Information is sent from the computer to the device through a cable.

port driver

A low-level driver that responds to a set of system-defined device control requests and possibly to an additional set of driver-defined (private) device control requests sent down by a corresponding class driver. A port driver insulates class drivers from the specifics of host bus adapters and synchronizes operations for all its class drivers.

port replicator

Low-cost docking-station substitute intended to provide convenient, one-step connection to multiple desktop devices.

POST

Power-on self-test. A procedure of the system BIOS that identifies, tests, and configures the PC in preparation for loading the operating system.

power management

Mechanisms in software and hardware to minimize system power consumption, manage system thermal limits, and maximize system battery life. Power management involves trade-offs among system speed, noise, battery life, processing speed, and AC power consumption. Power management is required for some system functions, such as appliance operations (including answering machine, furnace control, and so on).

power policy

For power management, the decisions that determine how to save energy and when to go to sleep, based on end-user preferences, application needs, and system hardware capabilities.

power resources

Resources such as power planes, clock sources, and so on that a device requires to operate in a given power state.

power sources

The battery and AC adapter that supply power to a platform.

program guide

The on-screen user interface that allows users to select, manage, and search television programs and other content-viewing options.

property

In WDM and Windows NT/Windows 2000 device driver models, an aspect of the device or stream that can be set or retrieved, such as volume level.

property set

In WDM and Windows NT/Windows 2000 device driver models, a method defined to set and get properties on a driver. Each property set has a unique identifier, which represents types of related information and is used to access the property set.

Px64

Also CCITT Recommendation H.261. A draft standard for motion video compression in videophone and teleconferencing applications, designed for 64-Kbps transmission channels.