L

L2 cache - level2 cache
Cache memory installed is called level 2 cache because level 1 cache is already on the CPU. Cache memory is high speed storage used as a transfer point for frequently used data between the CPU and the hard disk or RAM memory. Cache memory is used because it improves computer performance making it faster. Cache memory is usually either fast RAM memory or a specific region of the hard disk set aside for this specific use.

LAN - local area network
A network of personal or desktop computers usually in close proximity (in the same office or on the same floor of a building) hooked together so common resources like files, data, and printers can be used by an entire group of workers.

landscape
The orientation of a document or graphic to be horizontal; i.e., the width is greater than the height. See also portrait.

laptop
A portable computer slightly larger than a notebook computer. These computers are more expensive than desktop computers and can run on batteries for a short period of time.

laser printer
A printer that uses a laser beam to produce high quality text and graphic images. At this time, laser printers are the best resolution printers, come in black and white or color, and are the most expensive commercial personal printers.

LCD - liquid crystal display
The portable computer display screens filled with liquid crystals. There are 2 common types: the high quality active matrix screen displays and the lower quality passive matrix displays.

LED - light emitting diode
LEDs are the small green, yellow, orange, or red lights commonly found in computers and other small electronic devices. They are semiconductor diodes; i.e., containing 2 semiconductors sandwiched together.

level2 cache - L2 cache
Cache memory installed is called level 2 cache because level 1 cache is already on the CPU. Cache memory is high speed storage used as a transfer point for frequently used data between the CPU and the hard disk or RAM memory. Cache memory is used because it improves computer performance making it faster. Cache memory is usually either fast RAM memory or a specific region of the hard disk set aside for this specific use.

light emitting diode - LED
LEDs are the small green, yellow, orange, or red lights commonly found in computers and other small electronic devices. They are semiconductor diodes; i.e., containing 2 semiconductors sandwiched together.

Linux
Linux is an operating system that is very fast and stable. It can run on most platforms including PDAs; other platforms not yet compatible are under development. Since it is based on the Unix system, it can run all Unix software and is preferred by ISPs. It is gradually making headway in the personal computing market, and can be downloaded free over the Internet.

liquid crystal display - LCD
The portable computer display screens filled with liquid crystals. There are 2 common types: the high quality active matrix screen displays and the lower quality passive matrix displays.

Lisp
Lisp was the second programming language developed after FORTRAN. It is usually interpreted, is fairly portable but not fast.

load
The common use of load or loading is to place the machine-language instructions of an program, or some data, into memory.

local area network - LAN
A network of personal or desktop computers usually in close proximity (in the same office or on the same floor of a building) hooked together so common resources like files, data, and printers can be used by an entire group of workers.

LocalTalk
The hardware built into Macintosh® computers used for networking using the AppleTalk® protocol.

login
A process (i.e., noun) to gain access to a server using a user name and password.

log in
The action (i.e., verb) to send a user name and password to a server and gaining access to that server.

logout
A process (i.e., noun) to disconnect the link to a server that required a user name and password.

log out
The action (i.e., verb) of disconnecting the link to a server access with a user name and password.

locked file
A file that is in use, or one that has been protected or in some way limited is usage (i.e., read only files). For instance, a file opened in an application can not be deleted until it is closed from that application.

lossless compression
A compression algorithm that reduces the size of a file without losing any image quality and can be restored to its original form. This type of compression can not compress the file as much as lossy compression but no image quality is lost.

lossy compression
A compression algorithm that reduces the size of a file and also reduces image quality. It can not be restored to its original form but can compress to a greater degree than lossless compression.

low resolution
Low resolution typically implies that image quality is not high; i.e., the image is not as sharp as a high resolution image. Resolution can be measured in pixels per inch or DPI. For example, a low resolution graphic may be 72 DPI while a low resolution scanner may be able to scan images only at 300 DPI.

LPT1
The first parallel port on PC computers that typically is used as a connection to printers. Parallel ports are faster than serial ports because they can send more than 1 bit of data simultaneously.

luminance
A measure of the total amount of light coming from a given surface area. The subjective description of luminance is brightness. Luminance along with hue and saturation are part of the HLS color model system.

M

Macintosh®
First developed by Apple Computers® in 1984 and one of the first computers to use a GUI. Older Macintosh® computers used the 680x0 chips while most Macintosh® computers from 1996 on use the PowerPC Platform.

MacBinary
A file format used by Macintosh® computers to transfer files to other computers. MacBinary files have a ".bin" extension.

MacOS
The operating system used by Macintosh® computers and developed by Apple Computers®.

macro
Typically used to mean a sequence of recorded keystrokes that can be played back using a shortcut keystroke to re-do the recorded task(s) quickly.

mailbox
An email file used to store mail sent, received, or to be deleted.

maximize
A process of increasing the size of the active window to fill the desktop.

MB - megabyte
Approximately 1,000,000 bytes or 1,000 kilobytes. Exactly 1,048,576 bytes (1,024 kb) calculated from 2 to the 20th power.

Mbps - megabits per second
1 Mbps is approximately 1,000,000 bits per second, and refers to the speed of data transmission.

MCAD - mechanical computer-aided design
A specific type of CAD that is used in the design of mechanical structures like bridges, cars, etc.

mechanical computer-aided design - MCAD
A specific type of CAD that is used in the design of mechanical structures like bridges, cars, etc.

megabits per second - Mbps
1 Mbps is approximately 1,000,000 bits per second, and refers to the speed of data transmission.

megabyte - MB
Approximately 1,000,000 bytes or 1,000 kilobytes. Exactly 1,048,576 bytes (1,024 kb) calculated from 2 to the 20th power.

MegaFLOPS - million floating point operations per second
A measure of a computer's speed. A MegaFLOP refers to do 1 million floating decimal point calculations in 1 second.

megahertz - MHz
A million Hertz, where a Hertz is one cycle (or wave) per second. MHz are often used to describe a processor's speed with a greater MHz implying a faster processor. This is true only in the case where everything else is held constant and the only difference is the MHz or speed of the processor. In most cases, a comparison of the processor's MHz will not reveal which processor is faster; in fact, many processor's with slower MHz can actually process a task (e.g., apply a filter to a Photoshop graphic) faster than another processor with a higher MHz. (The term clock speed is often used in stead of MHz.)

memory
A temporary storage of an application, parts of an application, or files. Not to be confused with a hard drive which typically stores files or applications on a permanent or semi-permanent basis. There are a variety of different types of memory including RAM, ROM, VRAM, PRAM, DRAM, SRAM, and flash memory.

menu
A list of options for a given GUI operating system or application.

menu bar
The bar at the top of a window in an application or the top of the desktop in a GUI operating system that lists all the titles of the drop down menus. Some menu bar options do not have drop-down menus and that menu bar title is the entire menu (e.g., some Help options take the user to a Help file when clicked and do not produce a drop-down menu).

MFLOPS - million floating point operations per second
A measure of a computer's speed. A MFLOP refers to do 1 million floating decimal point calculations in 1 second.

MHz - megahertz
A million Hertz, where a Hertz is one cycle (or wave) per second. MHz are often used to describe a processor's speed with a greater MHz implying a faster processor. This is true only in the case where everything else is held constant and the only difference is the MHz or speed of the processor. In most cases, a comparison of the processor's MHz will not reveal which processor is faster; in fact, many processor's with slower MHz can actually process a task (e.g., apply a filter to a Photoshop graphic) faster than another processor with a higher MHz. (The term clock speed is often used in stead of MHz.)

Microsoft® Disk Operating System - MS-DOS
The operating system developed by Microsoft® and used on most PCs. MS-DOS is a command-line interface (CLI) rather than a GUI and can run only on x86 chips. Both Microsoft® Windows® 3.1 and 95 can be used on top of MS-DOS to create a GUI. MS-DOS is sometimes referred to as simply DOS.

MIDI - musical instrument digital interface
A standard file format and control language used to specify musical notes and timing. The code can be written and outputted to a MIDI-compatible musical instrument (e.g., synthesizer) or it can be created by a MIDI-compatible musical instrument attached to a computer.

million floating point operations per second - MegaFLOPS (or MFLOPS).
A measure of a computer's speed. A MegaFLOP refers to do 1 million floating decimal point calculations in 1 second.

millions of instructions per second - MIPS
A measure of the speed of a CPU; in this case, the number of instructions a CPU can process per second. Since different processors require different numbers of instructions to perform the same task (RISC requires more instructions than CISC), and since a variety of other factors play a role in the overall computer's "speed," a greater number of MIPS processed (like MHz) does not necessarily imply a "better" computer.

MIME - multi-purpose Internet mail extensions
A protocol used to transfer non-ASCII files such as video, audio, and graphics as an email attachment.

minimize
A process of decreasing the size of the active window on the desktop. In the Microsoft® Windows® operating system, the active window is reduced to a small title bar at the bottom of the desktop. In Macintosh® computers, the active window is hidden except for its title bar. The title bar is not reduced in width and is not moved to the bottom of the desktop.

MIPS - millions of instructions per second
A measure of the speed of a CPU; in this case, the number of instructions a CPU can process per second. Since different processors require different numbers of instructions to perform the same task (RISC requires more instructions than CISC), and since a variety of other factors play a role in the overall computer's "speed," a greater number of MIPS processed (like MHz) does not necessarily imply a "better" computer.

modulator-demodulator - modem
A device used as a bridge between a desktop computer and the telephone lines. The modem converts digital signals from the computer into analog signals which can be sent over telephone lines. If the message is sent to a server, then another modem must first receive the analog signal, convert it back to a digital signal, and then pass it on the server.

modem - modulator-demodulator
A device used as a bridge between a desktop computer and the telephone lines. The modem converts digital signals from the computer into analog signals which can be sent over telephone lines. If the message is sent to a server, then another modem must first receive the analog signal, convert it back to a digital signal, and then pass it on the server.

monochrome
Monochrome means literally one color and refers to one-color monitors where there is one color associated with background and one for the foreground. The common monochrome monitors are white on a black background or green on a black background. Monitors that have shades of gray are not monochrome but gray-scale monitors.

Mosaic
The first widely used web browsers available free and developed by NCSA.

motherboard
The main circuit board of the computer that contains the CPU, the RAM, the SBus, the ports, the BIOS, and expansion slots. (Also called system board.)

Motorola
The manufacturer of the 680x0 chip and a co-developer and manufacturer of the PowerPC chip.

mouse
An input device that controls the location of the cursor. The mouse works with a small ball that rolls underneath as the mouse housing is moved. The rolling ball's motion can be detected and converted into an electronic signal which correspondingly moves the cursor on the monitor. There are variations to this design (e.g., track balls), and newer models use lasers and an optical/electical pad that detects the laser motion. These laser mouse is more sensitive to movements since there is an optical rather than a mechanical interface.

mouse button 1
The primary mouse button that starts applications, etc. On Macintosh® computers, mouse button 1 is the only button since it is a one button mouse. On PCs, the left-most button is mouse button 1.

mouse button 2
The secondary mouse button. There is no mouse button 2 on a Macintosh® computer mouse since it has only one button. On PCs, mouse button 2 is the right-most button.

moving pictures experts group - MPEG
A standard lossy compression to compress video and audio data streams.

MPEG - moving pictures experts group
A standard lossy compression to compress video and audio data streams.

MS-DOS - Microsoft® Disk Operating System
The operating system developed by Microsoft® and used on most PCs. MS-DOS is a command-line interface (CLI) rather than a GUI and can run only on x86 chips. Both Microsoft® Windows® 3.1 and 95 can be used on top of MS-DOS to create a GUI. MS-DOS is sometimes referred to as simply DOS.

MS-Windows®
A GUI interface operating system written by Microsoft® that can refer to a some or all of the Microsoft® Windows® operating systems developed (Windows® 3.1, Windows® 95, Windows® 98, Windows® 2000, Windows® NT, and Windows® CE).

multi-purpose Internet mail extensions - MIME
A protocol used to transfer non-ASCII files such as video, audio, and graphics as an email attachment.

multimedia
A package of information that usually includes several formats of information including video, audio, animation, graphics, and/or text. Because of the large size of multimedia files, many multimedia projects are available only on CD-ROMs.

multiprocessor
A computer with more than one CPU allowing parallel tasks to be completed simultaneously.

multisync
The ability of a monitor to run at different scan rates which permit different resolutions.

multitasking
The process of running two or more tasks at the "same" time. Actually, the programs take turns using the available input/output ports and the CPU. There are different types of multitasking: Cooperative multitasking is a system that requires programs to take turns using the CPU while preemptive multitasking is a system that prioritizes programs, stopping some programs to allow others to access the CPU.

multiuser
A system that allows more than one user to access information in a sequential fashion in a given time frame.

musical instrument digital interface - MIDI
A standard file format and control language used to specify musical notes and timing. The code can be written and outputted to a MIDI-compatible musical instrument (e.g., synthesizer) or it can be created by a MIDI-compatible musical instrument attached to a computer.