P

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 System Design Guide, 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 a display subsystem.

PCM  Pulse coded 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, usually 16 bits per sample.

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.

Plug and Play  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, but 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 run-time configuration services for system-board devices after start-up. See also ACPI.

power management  Mechanisms in software and hardware to minimize system power consumption, to manage system thermal limits, and to maximize system battery life. Power management involves trade-offs among system speed, noise, battery life, processing speed, and power consumption.

push technology  In client/server applications, to send data to a client without the client requesting it—for example, sending e-mail. In contrast, the World Wide Web is based on a pull technology, where the client browser must request a web page before it is sent. Broadcast media are push technologies because they send information out regardless of whether anyone is tuned in.