Technical information

© CLEAPSS 2005 1651 ICT in the Science Department
K, kb or kbyte
One kilobyte: approximately one thousand bytes, actually 2
10
or 1 024 bytes, used as a
measure of the size of a computer’s memory or of the information to be held. (Not to be
confused with k as in kg which means exactly 1 000 units.)
Kb This abbreviation is sometimes used to refer to kilobits.
Key strip A piece of card or paper designed to fit close to the function keys on a computer keyboard
enabling the user to mark the function of any of these keys.
Lag The delay between two events, typically between a request and a reply over a network or
the Internet.
LAN Local Area Network.
Laptop A portable computer. Also sometimes called a ‘notebook computer’.
LCD Liquid Crystal Display. A thin, flat type of display that is part of many electronic devices
from wristwatches to laptops and PDAs. Traditionally black characters on a grey
background but now able to produce a colour display that rivals CRT technology.
Lead A cable used to connect components such as connecting a peripheral to a computer.
LED Light-Emitting Diode. A small indicator light.
Load Several possible meanings. To copy information from storage, say from hard disk or CD,
into memory for it to be processed or, if it is a program, to be executed. The amount of
current drawn by an electronic device. The amount of traffic or demand on a
communications line.
Logic gate A device which controls the flow of information under certain conditions (eg an AND gate
only opens when one condition AND others are true); it may be mechanical, electrical or
electronic.
LPT Line Print Terminal. The logical device name for a printer.
Luma See Luminance.
Lumen (lm) A unit of measurement of brightness. The brightness of data projectors is typically
specified in lumen. One lumen is equivalent to one candela per square meter at unit
distance from the light source.
Luminance The signal, or part of a composite signal, that carries the brightness information.
Represented by the letter ‘Y’. Colour information is transmitted as luminance (brightness)
and chrominance (colour). The luminance is a weighted sum of the RGB colours.
Mac Macintosh computer.
MAC address Media Access Control address. A MAC address is a unique identifier physically stored
inside a network card or similar network device.
Mac OS The operating system of Macintosh computers.
Macro Within an application, a recorded set of commands that may be created and assigned to a
key or menu.
Male / female
connector
A male connector that has outward facing pins designed to fit a female connector that has
corresponding sockets for the pins.
Mapped drive A network server-based drive that is assigned a local drive letter.
Master / slave An arrangement whereby a primary device or master controls a secondary or slave
device that is connected to it.
Mb Megabits, ie, ‘one million’ (1048576) bits.
Mbyte, MB
One megabyte: approximately one million bytes, actually 2
20
or 1 048 576 bytes, used as
a measure of the size of a computer memory or disc.
Memory A device capable of storing and retrieving information. Typically refers to the amount of
RAM accessible to a computer.
Memory card /
stick
A small card / stick on which information can be stored for later transfer to another device.
For example, some cameras store images on memory cards that can be inserted into a
PC to transfer the images.
Microchip A number of connected circuit elements fabricated on a single chip of silicon or other
semiconductor material.