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Glossary of Computer Hardware Terms - The Letters J, K, and L

written by: Jesma•edited by: J. F. Amprimoz•updated: 12/30/2008

Definitions and explanations of computing terms beginning with the letters J, K, and L. Here we explain the meaning of JavaScript, Jumper, Kernel, L1/L2 Cache, LED and Local Area Network.

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    The Letter J


    An object oriented programming language similar to C++, developed by Sun MicroSystems and used in the creation of network-based applications.


    JavaScript is a scripting language used in web development, primarily in websites. It was designed to look like Java and uses some of the same naming conventions, but the similarities end there. The primary influences of JavaScript are the Self and Scheme programming languages.


    An input device used in computer gaming, primarily for games that utilize flight simulation. May also be used with other games, though less commonly. Older versions connected through a serial port. Modern Joysticks are USB based.


    A plastic covered metal clip that sets over two pins on a circuit board. Jumpers connect pins, completing an electric circuit that changes configurations on devices, or can be used to kick start a switch.

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    The Letter K


    The core component of an operating system. Provides the basic architecture that the system is built upon.

    Keyboard Macro

    A series of keystrokes that are automatically input when a single key is pressed. Used often in Office application delivery for improved speed of performance and in PC gaming to take the place of laborious, systematic keystroke sequences.


    A unit of storage equal to 1,024 bytes.

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    The Letter L

    L1 Cache

    Stands for level one cache. A memory cache that is built into the CPU core to temporarily hold data being processed.

    L2 Cache

    Stands for level two cache. A memory cache housed outside the processor core, but still a part of the CPU. Typically larger and slower than the L1 cache.

    Laptop Computer

    A computer system that is smaller than a briefcase but larger than a notebook. Typically has a clamshell design where the keyboard and display are on separate halves of the system. Named for its use as a computer that can be used while resting in the users lap.

    Laser Printer

    A type of printer that is a combination of an electro-static copying machine and a printer. An electro-static charge is used to transfer toner onto the page, which is then fused onto the paper due to very high heat. As a result, pages are expelled from the printer very quickly and output in a completely dry state. Laser printers are fast, accurate, and don't require as much resupplying of printing media as Inkjet's do. They are, however, much more expensive.

    LCD - Liquid Crystal Display

    A display that uses liquid crystal sealed between two pieces of glass. Must be coupled with a back-light in order to display images. Quickly replacing CRTs as the computer display standard. Offer high resolution and true colors in a compact design.

    LED - Light-Emitting Diode

    A semiconductor diode that emits light when a current is passed through it.

    Local Area Network

    The connection of multiple computers using a network adapter card, and often a hub, switch, or router.