Dell PowerEdge R900 - Manual (Page 178)

178 Glossary
NVRAM — Nonvolatile random-access memory. Memory that does not lose its
contents when you turn off your system. NVRAM is used for maintaining the date,
time, and system configuration information.
P A R I T Y
— Redundant information that is associated with a block of data.
P A R T I T I O N
— You can divide a hard drive into multiple physical sections called
partitions with the fdisk command. Each partition can contain multiple logical drives.
You must format each logical drive with the format command.
PCI — Peripheral Component Interconnect. A standard for local-bus
implementation.
PDU — Power distribution unit. A power source with multiple power outlets that
provides electrical power to servers and storage systems in a rack.
peripheral
An internal or external device, such as a diskette drive or keyboard, connected to a
system.
PGA — Pin grid array. A type of processor socket that allows you to remove the
processor chip.
P I X E L
— A single point on a video display. Pixels are arranged in rows and columns to
create an image. A video resolution, such as 640 x 480, is expressed as the number of
pixels across by the number of pixels up and down.
POST — Power-on self-test. Before the operating system loads when you turn on your
system, the POST tests various system components such as RAM and hard drives.
P R O C E SS O R
— The primary computational chip inside the system that controls the
interpretation and execution of arithmetic and logic functions. Software written for
one processor must usually be revised to run on another processor. CPU is a synonym
for processor.
P R O T E CT E D M O D E
— An operating mode that allows operating systems to implement
a memory address space of 16 MB to 4 GB, multitasking, and virtual memory—a
method for increasing addressable memory by using the hard drive. The Windows
2000 and UNIX 32-bit operating systems run in protected mode. MS-DOS cannot run
in protected mode.
PS/2 — Personal System/2.
PXE — Preboot eXecution Environment. A way of booting a system via a LAN
(without a hard drive or bootable diskette).
RAC — Remote access controller.