Specifications

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Appendix A Glossary
National Institute of Standards and
Technology (NIST) A nonregulatory federal
agency within the U.S. Commerce Department’s
Technology Administration. Founded in 1901,
NIST’s mission is to promote U.S. innovation and
industrial competitiveness by advancing measure-
ment science, standards, and technology.
NetBEUI (NetBIOS Extended User Interface)
A network protocol used primarily by Windows NT
and Windows 9x and most suitable for small peer-
to-peer networks. NetBEUI is not supported by
Microsoft in Windows XP and above but can still
be manually installed for use in troubleshooting
computers.
NetBIOS (Network Basic Input/Output
System) A commonly used network protocol
originally developed by IBM and Sytek for PC local
area networks. NetBIOS provides session and trans-
port services (Layers 4 and 5 of the OSI model).
NetWare Novell’s server-based network for large
businesses. NetWare 5 and NetWare 6 are designed
to work well with IP-based networks.
network A system in which several independent
computers are linked to share data and peripherals,
such as hard disks and printers.
Network Address Translation (NAT) An
Internet standard allowing a router on a local area
network to use one set of IP addresses internally,
while using a second set of addresses for external
traffic.
network attached storage (NAS) A hard disk-
based storage device or array that plugs into the
network and has its own IP address.
network interface card (NIC) An adapter that
connects a PC to a network.
Network Layer In the OSI reference model, the
layer that switches and routes the packets as neces-
sary to get them to their destinations. This layer is
responsible for addressing and delivering message
packets. See also OSI.
Network Time Protocol (NTP) A standard
Internet protocol allowing for the accurate synchro-
nization of clocks on a network.
NiCad The oldest of the three battery technolo-
gies used in portable systems, nickel cadmium bat-
teries are rarely used in portable systems today
because of their shorter life and sensitivity to
improper charging and discharging. See also NiMH
and lithium-ion.
NiMH A battery technology used in portable sys-
tems. Nickel metal-hydride batteries have approxi-
mately a 30% longer life than NiCads, are less
sensitive to the memory effect caused by improper
charging and discharging, and do not use the envi-
ronmentally dangerous substances found in
NiCads. Newer lithium-ion (Li-ion) batteries are far
superior. NiMH batteries can sometimes be used in
place of NiCads.
NLX A new low-profile motherboard form factor
standard that is basically an improved version of
the semiproprietary LPX design. It’s designed to
accommodate larger processor and memory form
factors and incorporate newer bus technologies,
such as AGP and USB. Besides design improve-
ments, it is fully standardized, which means you
should be able to replace one NLX board with
another from a different manufacturer—something
that was not normally possible with LPX.
node A device on a network. Also any junction
point at which two or more items meet.
noise Any unwanted disturbance in an electrical
or mechanical system.
noninterlaced monitor A desirable monitor
design in which the electron beam sweeps the
screen in lines from top to bottom, one line after
the other, completing the entire screen in one pass.
Virtually all CRTs sold recently for desktop use are
noninterlaced.
nonvolatile memory (NVRAM) Random-
access memory whose data is retained when power
is turned off. ROM/EPROM/EEPROM (flash) mem-
ory are examples of nonvolatile memory. Some-
times NVRAM is retained without any power
whatsoever, as in EEPROM or flash memory
devices. In other cases, the memory is maintained
by a small battery. NVRAM that is battery main-
tained is sometimes also called CMOS memory
(although CMOS RAM technically is volatile).
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