Dell POWEREDGE R805 - Manual (Page 19)

LAN — Local area network. A LAN is usually confined to the same building or a few nearby buildings, with all equipment linked by wiring dedicated specifically
to the LAN.
lb — Pound(s).
LCD — Liquid crystal display.
LED — Light-emitting diode. An electronic device that lights up when a current is passed through it.
LGA—Land grid array. A type of processor socket. Unlike the PGA, the LGA interface has no pins on the chip; instead, the chip has pads that contact pins on
the system board.
Linux — An operating system similar to the UNIX® operating system that runs on a variety of hardware systems. Linux is open source software, which is
freely available; however, the full distribution of Linux along with technical support and training are available for a fee from vendors such as Red Hat®
Linux® software.
local bus — On a system with local-bus expansion capability, certain peripheral devices (such as the video adapter circuitry) can be designed to run much
faster than they would with a traditional expansion bus. See also bus.
LVD — Low voltage differential.
m — Meter(s).
mA — Milliampere(s).
MAC address — Media Access Control address. Your system's unique hardware number on a network.
mAh — Milliampere-hour(s).
Mb — Megabit(s); 1,048,576 bits.
MB — Megabyte(s); 1,048,576 bytes. However, when referring to hard-drive capacity, the term is often rounded to mean 1,000,000 bytes.
Mbps — Megabits per second.
MBps — Megabytes per second.
MBR — Master boot record.
memory address — A specific location, usually expressed as a hexadecimal number, in the system's RAM.
memory module — A small circuit board containing DRAM chips that connects to the system board.
memory — An area in your system that stores basic system data. A system can contain 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).
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 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.
processor — 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.
protected mode — An operating mode that allows operating systems to implement:
l A memory address space of 16 MB to 4 GB
l Multitasking
l 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.
RAID — Redundant array of independent disks. A method of providing data redundancy. Some common implementations of RAID include RAID 0, RAID 1,
RAID 5, RAID 10, and RAID 50. See also
guarding, mirroring, and striping.
RAM — Random-access memory. The system's primary temporary storage area for program instructions and data. Any information stored in RAM is lost when
you turn off your system.
RAS — Remote Access Service. This service allows users running the Windows operating system to remotely access a network from their system using a
modem.