Specifications

Glossary
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LBA (logical block addressing) A method
used with SCSI and IDE drives to translate the
cylinder, head, and sector specifications of the drive
to those usable by an enhanced BIOS. LBA is used
with drives that are larger than 528MB and causes
the BIOS to translate the drive’s logical parameters
to those usable by the system BIOS.
LCC (leadless chip carrier) A type of inte-
grated circuit package that has input and output
pads rather than leads on its perimeter.
LCD (liquid crystal display) A display that
uses liquid crystal sealed between two pieces of
polarized glass. The polarity of the liquid crystal is
changed by an electric current to vary the amount
of light that can pass through. Because LCD dis-
plays do not generate light, they depend on the
reflection of ambient light or backlighting the
screen. The best type of LCD, the active-matrix or
thin-film transistor (TFT) LCD, offers fast screen
updates and true color capability.
LED (light-emitting diode) A semiconductor
diode that emits light when a current is passed
through it.
LED printer A printer that uses an LED instead
of a laser beam to discharge the drum.
legacy port I/O ports used on systems before
the development of the multipurpose USB port.
Serial, parallel, keyboard, and PS/2 mouse ports are
legacy ports.
letterbox Refers to how wide-screen movies are
displayed on TV or monitor screens with normal
aspect ratios of 4:3. Because wide-screen movies
have aspect ratios as high as 16:9, the wide-screen
image leaves blank areas at the top and bottom of
the screen. See also aspect ratio.
LGA (land grid array) A type of chip socket
that moves the pins from the processor to the
motherboard. The pins (lands) connect to pads on
the back side of the processor. The first LGA design
is Socket 775.
LIF (low insertion force) A socket that
requires only a minimum of force to insert a
chip carrier.
light pen A handheld input device with a light-
sensitive probe or stylus connected to the com-
puter’s graphics adapter board by a cable. Used for
writing or sketching onscreen or as a pointing
device for making selections. Unlike mice, it’s not
widely supported by software applications.
line-interactive UPS A UPS design that uses a
two-way AC/DC inverter to charge the battery and
provide power from the battery after AC power
fails. It’s the simplest type of UPS suitable for
server use.
line voltage The AC voltage available at a stan-
dard wall outlet, nominally 110V–120V in North
America and 220V–230V in Europe and Japan.
linear tape-open (LTO) A family of open stan-
dards for tape backups whose first products were
introduced in mid-2000. LTO was jointly developed
by Seagate, IBM, and Hewlett-Packard. Ultrium for-
mat products have capacities of up to 800GB (2:1
compression). The faster but smaller-capacity
Accelis format was never manufactured. See also
Ultrium.
lithium-ion A portable system battery type that
is longer-lived than either NiCad or NiMH tech-
nologies, can’t be overcharged, and holds a charge
well when not in use. Lithium-ion batteries are also
lighter weight than the NiCad and NiMH technolo-
gies. Because of these superior features, Li-ion bat-
teries have come to be used in all but the very low
end of the portable system market.
local area network (LAN) The connection of
two or more computers, usually via a network
adapter card or NIC.
local bus A generic term used to describe a bus
directly attached to a processor that operates at the
processor’s speed and data-transfer width.
local echo A modem feature that enables the
modem to send copies of keyboard commands and
transmitted data to the screen. When the modem is
in command mode (not online to another system),
the local echo usually is invoked through an ATE1
command, which causes the modem to display the
user’s typed commands. When the modem is
online to another system, the local echo is invoked
by an ATF0 command, which causes the modem to
display the data it transmits to the remote system.
logical drive A drive as named by a DOS drive
specifier, such as C: or D:. Under DOS 3.3 or later, a
single physical drive can act as several logical
Appendix A
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