TYAN S5535 Quick Reference Manual page 96

I/O (Input/Output): the connection between your computer and another piece of
hardware (mouse, keyboard, etc.)
IRQ (Interrupt Request): an electronic request that runs from a hardware device to
the CPU. The interrupt controller assigns priorities to incoming requests and
delivers them to the CPU. It is important that there is only one device hooked up to
each IRQ line; doubling up devices on IRQ lines can lock up your system. Plug-n-
Play operating systems can take care of these details for you.
Latency: the amount of time that one part of a system spends waiting for another
part to catch up. This occurs most commonly when the system sends data out to a
peripheral device and has to wait for the peripheral to spread (peripherals tend to
be slower than onboard system components).
NVRAM: ROM and EEPROM are both examples of Non-Volatile RAM, memory that
holds its data without power. DRAM, in contrast, is volatile.
Parallel port: transmits the bits of a byte on eight different wires at the same time.
PCI (Peripheral Component Interconnect): a 32 or 64-bit local bus (data pathway)
which is faster than the ISA bus. Local buses are those which operate within a
single system (as opposed to a network bus, which connects multiple systems).
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 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.
PnP (Plug-n-Play): a design standard that has become ascendant in the industry.
Plug-n-Play devices require little set-up to use. 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 with
the goal of allowing networked-based booting to boot using industry standard
protocols.
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