User's Manual

Glossary 171
several different forms of memory, such as integrated memory (ROM and RAM) and
add-in memory modules (DIMMs).
MHz — Megahertz.
mirroring — A type of data redundancy in which a set of physical drives stores data
and one or more sets of additional drives stores duplicate copies of the data. Mirroring
functionality is provided by software. See also guarding, integrated mirroring, striping,
and RAID.
mm — Millimeter(s).
ms — Millisecond(s).
MS-DOS
®
— Microsoft Disk Operating System.
NAS — Network Attached Storage. NAS is one of the concepts used for implementing
shared storage on a network. NAS systems have their own operating systems,
integrated hardware, and software that are optimized to serve specific storage needs.
NIC — Network interface controller. A device that is installed or integrated in a
system to allow connection to a network.
NMI — Nonmaskable interrupt. A device sends an NMI to signal the processor about
hardware errors.
ns — Nanosecond(s).
NTFS — The NT File System option in the Windows 2000 operating system.
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.
parity — Redundant information that is associated with a block of data.
partition — 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.
pixel — 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
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