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Explanatory Dictionary - JKL





Java - Programming Language

Java was developed by Sun Microsystems and went mainstream in 1995, it is an implementation of the OAK language.

Java is an object orientated high level general purpose programming language that has become widely used on the WWW, due to its cross platform compatibility.

Java source code is compiled into bytecode and can then be run by Java interpreters and runtime enviroments (Java Virtual Machines) which are available for most platforms including Windows, Unix and Macintosh OS.

Java applets are small applications written in Java and are common within the WWW enviroment, for example a chat applet can be downloaded and executed within the run time enviroment integrated into your web browser (Netscape Navigator, Internet explorer, etc).

Javascript - Scripting Language

Javascript is Netscape's scripting language for client - server applications. Javascript is used by browsers to perform tasks that HTML would not be able to achieve by itself.

Javascript can be a very powerful and useful cross platform language when used correctly. It is fairly simple for someone with no programming experience to learn and can add some interesting features to a website, for those that have programming experience in another language such as C++ then it is very easy to pick up.

For those who are not quite ready or don't have time to learn the language then there are plenty of places on the Internet to get FREE scripts that you can just paste into an existing web page.

JPEG - Joint Photographics Experts Group

This is an image format named after its developers that can compress images to very small file sizes, commonly used on the internet due to faster image transfer rates.

JPEG images unlike its GIF counterpart can contain thousands of colours which makes the format ideal for compressing images such as photographs.

The JPEG format can compress images up to around 10% of their original file size without losing too much quality (depending on the image used) although the image will lose its sharpness.

JPEG files use the .jpg and .jpeg file extensions.

Kbps - kilobits per second

A measurement typically used to describe a modem's data transfer in kilobits (1000) per second. (note the k in this instance means 1000, not 1024 unlike Kb)

It is also used to describe data transfer in various different communication peripherals and/or ports.

A modem or port's data transfer capability is restricted by the communications line through which it communicates, most standard "dial up" connections support up to 56kbps which gives a data transfer of around 6Kb (6 x 1024 bytes) per second.

Kernel

Kernel refers to the part of an operating system that controls memory and disk management as well as other tasks including process and task management.

As the kernel controls the memory allocation for the application it needs to be loaded first (at boot) and kept in memory.

Keyboard Shortcuts - Hotkeys

Keyboard shortcuts can save time and make life easier when using applications, they are achieved by pressing a combination of keys, normally holding down the CONTROL (CTRL) key and pressing another key, then letting go of the CONTROL (CTRL) key, most applications (programs) have built in keyboard shortcuts often referred to as HOTKEYS.

Kilobyte - KB

A measurement used in digital systems to describe storage capacity, 1 Kilobyte is equal to 1024 (210) Bytes in digital systems.

LAN - Local Area Network

These are common-place in offices and are used to link 2 or more computers for the purpose of sharing files and/or peripherals.

A LAN refers to a network that spans a relatively small geographical area and/or is limited to one segment, for example an office floor-space.

LANs provide high speed data transfer (100Kbps to 1Gbps) between directly connected machines using different network topologies and protocols, See also Ethernet and WAN.

WLAN refers to a Wireless LAN which uses radio waves instead of cables for data transfer, this type of LAN is extremely useful but can be expensive depending on the amount of terminals involved.

LCD - Liquid Crystal Display

LCD refers to a display technology used commonly in notebooks and PDAs, LCD technology has been around for years, it was first suggested in 1963 by George heilmeier & co at RCA's laboratory in Princeton, New Jersey.

A Liquid Crystal Display works by having two layers of polarised material with liquid crystal in between, when an electrical current is applied to the liquid crystal molecules they become scattered allowing light to pass through.

Modern LCD displays use either passive or active (TFT) matrixes, the later producing a sharper image but at a higher cost.

LPT - Line Printing Terminal

The common name given to a Parallel Port on IBM and compatible machines.

Although people refer to the DB-25 female connector on the back of a PC as an LPT port, technically an LPT port is simply a parallel port set to LPT(x) with an I/O address and IRQ assigned to it, in the same way as a COM(x) port is actually a serial port set to COM(x).

Usually an individual machine will have 2 LPT ports although you can normally assign up to 3, these ports each with their own name LPT1, LPT2 and LPT3, although they were designed primarily for printers there is a wide variety of peripherals that can be connected to these ports.