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• LAN:
  A computer network that spans a relatively small area. Most LANs are confined to a single building or group of buildings. However, one LAN can be connected to other LANs over any distance via telephone lines and radio waves. A system of LANs connected in this way is called a wide area network (WAN). 
  
  Most LANs connect workstations and personal computers. Each node (individual computer ) in a LAN has its own CPU with which it executes programs, but it is also able to access data and devices anywhere on the LAN. This means that many users can share expensive devices, such as laser printers, as well as data. Users can also use the LAN to communicate with each other, by sending e-mail or engaging in chat sessions.
  
  There are many different types of LANs Ethernets being the most common for PCs. Most Apple Macintosh networks are based on Apple's AppleTalk network system, which is built into Macintosh computers.
   

• Layer:
  In networking, layers (also called Levels) refer to software protocols. Each layer builds on the layer beneath it as part of an overall interactive transmission system.
   

• LBA:
  Known as: Logical Block Addressing. In a system using an enhanced BIOS and Operating System that supports the use of LBA, it would then be possible for the computer to use a larger hard drive. LBA allows for use of a unique sector number in each sector instead of referring to a cylinder, head and sector number configuration.
   

• LCD:
  Abbreviation of liquid crystal display, a type of display used in digital watches and many portable computers. LCD displays utilize two sheets of polarizing material with a liquid crystal solution between them. An electric current passed through the liquid causes the crystals to align so that light cannot pass through them. Each crystal, therefore, is like a shutter, either allowing light to pass through or blocking the light.
  
  Monochrome LCD images usually appear as blue or dark gray images on top of a grayish-white background. Color LCD displays use two basic techniques for producing color: Passive matrix is the less expensive of the two technologies. The other technology, called thin film transistor (TFT) or active-matrix, produces color images that are as sharp as traditional CRT displays, but the technology is expensive. Recent passive-matrix displays using new CSTN and DSTN technologies produce sharp colors rivaling active-matrix displays.
   

• LED:
  Abbreviation of light emitting diode, an electronic device that lights up when electricity is passed through it. LEDs are usually red. They are good for displaying images because they can be relatively small, and they do not burn out. However, they require more power than LCDs.
   

• LimeWire:
  A peer-to-peer Gnutella file sharing client which allows network users share files. LimeWire is a free open source software.
   

• Linker:
  A program specifically designed to combine or link together a large number of programs forming a single executable instruction set for these programs that can be loaded in to the systems memory for quick execution.
   

• Linux:
  A version of UNIX that runs on a variety of hardware platforms including x86 PCs, Alpha, PowerPC and IBM's product line. 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 Software and Caldera. Due to its stability, Linux has gained popularity with Internet Service Providers as the Operating System of choice for hosting Web servers. 
   

• Live Script: 
  This is the former name of Java Script. There are few updates between the two.
   

• LLTD (Link Layer Topology Discovery):
  A feature that helps users to troubleshoot their networks. LLTD automatically detects multiple network devices and gives a graphical presentation of the connected hardware to identify configuration errors.
   

• Logic:
  This is broken down into two categories:
  
  -Software Logic:
  The sequence of instructions performed by a program.
  -Hardware Logic:
  A set of circuit elements that perform a function.
   

• Login: 
  To attach to a computer. It has also come to represent your User ID command.
   

• Login Script:
  This is the small text file that is run by the server gateway to make the attachment between it and your computer.
   

• Loopback:
  A diagnostic test that returns the transmitted signal back to the sending device after it has passed through a network or across a particular link. The returned signal can then be compared to the transmitted one. The discrepancy between the two help to trace the fault. When trying to locate a faulty piece of equipment, loopbacks will be repeated, eliminating satisfactory machines until the problem is found.
   

• LVD: 
  Low Voltage Differential. A differential logic scheme using lower voltage levels than HVD.  

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