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PCI PIO (PCI Programmable Input/Output) modes: the data transfer modes
used by IDE drives. These modes use the CPU for data transfer (in contrast,
DMA channels do not). PCI refers to the type of bus used by these modes to
communicate with the CPU.
PCI-to-PCI bridge: allows you to connect multiple PCI devices onto one PCI
slot.
Pipeline burst SRAM: a type of RAM that can maintain it's data as long as
power is provided to the memory chips. In this configuration, SRAM requests
are pipelined, which means that larger packets of data are sent to the memory
at one time, and acted upon quickly. This type of SRAM operates at bus speeds
higher than 66MHz.
Pipelining: improves system performance by allowing the CPU to begin
executing a second instruction before the first is completed. A pipeline can be
likened to an assembly line, with a given part of the pipeline repeatedly
executing a set part of an operation on a series of instructions.
PM timers (Power Management timers): software timers that count down the
number of seconds or minutes until the system times out and enters sleep,
suspend, or doze mode.
PnP (Plug-n-Play): a design standard that has become ascendant in the
industry. Plug-n-Play devices require little set-up to use. Novice end users can
simply plug them into a computer that is running on a Plug-n-Play aware
operating system (such as Windows 98), and go to work. Devices and operating
systems that are not Plug-n-Play require you to reconfigure your system each
time you add or change any part of your hardware.
PXE (Preboot Execution Environment): one of four components that together
make up the Wired for Management 2.0 baseline specification. PXE was
designed to define a standard set of preboot protocol services within a client,
towards the goal of allowing networked-based booting to boot using industry
standard protocols.
RAID (Redundant Array of Independent Disks): a way for the same data to
be stored in different places on many hard drives. By using this method, the
data is stored redundantly, also the multiple hard drives will appear as a single
drive to the operating system. RAID level 0 is known as striping, where data is
striped (or overlapped) across multiple hard drives, but offers no fault-tolerance.
RAID level 1 is known as mirroring, which stores the data within at least two
hard drives, but does not stripe. RAID level 1 also allows for faster access time
and fault-tolerance, since either hard drive can be read at the same time. RAID
level 0+1 is both striping and mirroring, providing fault-tolerance, striping, and
faster access all at the same time.
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