L

LAN

Local area network. A group of computers and other devices dispersed over a relatively limited area and connected by a communications link that enables any device to interact with any other device on the network. Compare with WAN.

layered driver

One of a collection of drivers that responds to the same IRPs. Layered driver describes the highest-level and lowest-level drivers in a chain of layered drivers that process the same IRPs, along with all intermediate drivers in the chain.

legacy

Any feature in the PC system based on older technology for which compatibility continues to be maintained in other system components.

local bus

Usually refers to a system bus directly connected to the microprocessor on a system board. Used colloquially to refer to system board buses located closer to the microprocessor than are ordinary expansion buses (that is, with less buffering), which are therefore capable of greater throughput.

lossless compression

Ensures that the original data is exactly recoverable with no loss in image quality.

lossy compression

The original data is not completely recoverable. Although image quality may suffer, many experts believe that up to 95 percent of the data in a typical image may be discarded without a noticeable loss in apparent resolution.

LRU

Least-recently used. Algorithm for paging.

luminance

Used to describe the black-and-white component of a video signal. The amount of luminance contained in a video signal is directly related to the amount of light intensity. Also, brightness; one of the three image characteristics coded in composite television (represented by the letter Y). See YUV.