TYAN TOMCAT I815E Manual page 56

Appendix
Glossary
PCI PIO (PCI Programmable Input/Output) modes are the data transfer modes used
by IDE drives. These modes use the CPU for data transfer (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 is a fast secondary cache. It is used as a secondary cache
because SRAM is slower than SDRAM, but usually larger. Data is cached first to the
faster primary cache, and then, when the primary cache is full, to the slower secondary
cache.
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) are software timers that count down the
number of seconds or minutes until the system times out and enters sleep, suspend, or
doze mode.
PnP is an acronym for Plug and Play, a design standard that has become ascendant in
the industry. Plug and Play devices require little set-up to use. Novice end users can
simply plug them into a computer that is running on a Plug and Play-aware operating
system (such as Windows 98), and go to work. Devices and operating systems that are
not Plug and Play require you to reconfigure your system each time you add or change
any part of your hardware.
The term RAM (Random Access Memory), while technically referring to a type of
memory where any byte can be accessed without touching the adjacent data, is often
used to refer to the system's main memory. This memory is available to any program
running on the computer.
ROM (Read-Only Memory) is a storage chip which contains the BIOS, the basic
instructions required to boot the computer and start up the operating system.
SDRAM (Synchronous Dynamic RAM) is so-called because it can keep two sets of
memory addresses open simultaneously. By transferring data alternately from one set
of addresses, and then the other, SDRAM cuts down on the delays associated with
non-synchronous RAM, which must close one address bank before opening the next.
The serial port is so called because it transmits the eight bits of a byte of data along
one wire, and receives data on another single wire (that is, the data is transmitted in
serial form, one bit after another).
SIMM (Single In-line Memory Modules) are the most common form of RAM. They
must be installed in pairs, and do not have the carrying capacity or the speed of
DIMMs.
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