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Explanatory Dictionary - GHI





GHZ - Gigahertz

Gigahertz is a frequency measurement and it refers to billions of cycles per second, it is widely used in computing for processor specifications, for example a processor running at 2 GHz can handle 2 billion cycles per second. See also MHz, 1 GHz is equal to 1000 Mhz. Hertz is named after Physicist Heinrich Hertz.

GIF - Graphics Interchange Format

The GIF image format was developed by Compuserve and is widely used on the Internet due to its high compression (provided by Unisys) and subsequent small file size.

GIF files can be interlaced and animated making them a popular choice for web designers, however, due to the format being limited to only 256 colours the JPEG image format is used for more colour demanding images such as photos.

Animated GIFs which are essentially static images put in a sequence to create the animation can be created in programs such as Macromedia Flash.

Gigabyte - GB

This is a measurement used to describe 1024 Megabytes. Hard disk capacity is usually measured in Gigabytes.

1 Gigabyte is 1,073,741,824 Bytes.

Sometimes people/companies refer to a Gigabyte as 1000 megabytes, but when these figures relate to digital systems one Gigabyte is 1024MB not 1000MB, ie 230.

Gopher - Internet Service

Developed at the university of Minnesota around 1991. Gopher was a pre-WWW popular internet service which could search and browse through a network (internet). It was made virtually redundant when the WWW was conceived but is still used in some academic circles.

Graphics Card - Video Card

A Graphics Card also known as a Video Card is an internal device which controls and produces the display on your screen.

Graphic cards come with various specifications, and unless they are built-in to the motherboard (mainboard) they have their own RAM onboard. Some models boast a TV OUT feature which allows you to connect the Graphics card to your TV/VCR, this can be useful if your PC has a DVD player and you want to watch a DVD on your domestic TV.

Graphic cards also come with different slot types, although the most common now is the AGP (Accelerated Graphics Port) type you can still get PCI (Peripheral Component Interconnect) graphic cards for older motherboards.

The built-in (motherboard) graphic cards use the system's main RAM as their own, the amount of RAM assigned can be adjusted within your computer's BIOS setup.

GUI - Graphical User Interface

This is used to describe a user friendly environment which uses graphical images (such as icons) instead of a command line to interact with the computer, GUIs have made computers more user friendly and more accessible to any user no matter what experience they may have, a typical GUI is the Windows® operating system.

Hard Disk - Hard Drive

This is your computers main storage device, this is where you would normally keep your programs and files. These devices contain platters (disk like objects) that rotate at speeds of 5400 rpm and above, there is a device called an actuator that can be likened to an arm which moves across the platters and reads or writes the information through the use of READ/WRITE heads. the gap between the READ/WRITE heads and the platter is typically a lot less than the thickness of a human hair. The platters are made from an aluminium substance, these devices are a lot more reliable now than they used to be, although they can break down mechanically if you drop them !!!!.

Hardware - Components

This normally refers to your computer case and any components inside it, it can also refer to printers, scanners etc but these are more commonly known as peripherals. For example motherboards, modems, soundcards, memory (RAM), and graphics cards are all hardware.

Host - Hosting

Host refers to a computer running host software which is connected to a network and provides data/services to one or more computers.

A typical example of a host is a website host that stores and then serves pages and images to users via the internet, this is accomplished by running host software on the machine, the host software manages requests from other machines and fulfills the requests according to whatever protocol the machines are using.

HTML - HyperText Mark-up Language

This is an application of the (SGML) Standard Generalised Markup Language which is the international standard for Markup. It is a standard format for hypertext documents which includes webpages and alike.

HTTP - HyperText Transfer Protocol

HTTP has been in use on the WWW since around 1990 and refers to a client-server protocol by which two computers can communicate over a TCP/IP connection. HTTPS refers to a secure protocol that is using, for instance SSL.

Hub - Network Hub (Concentrator)

Hub (sometimes referred to as a concentrator) refers to a networking component which acts as a convergence point of a Network allowing the transfer of data packets.

In its simplest form a hub works by duplicating the data packets received via one Port and making it available to all ports, therefore allowing data sharing between all devices connected to the hub.

A passive hub simply allows the data packets to flow through it, a manageable hub allows the data transfer to be monitored and the ports to be configured individually.

IDE - Integrated Drive Electronics | ATA - Advanced Technology Attachment

IDE (also known as ATA) refers to a standard used in Hard Drives whereby the controller is integrated into the device, this standard saw the end of separate disk controllers for IDE devices, see also SCSI.

IEEE 1394 - Firewire - iLink

A fast digital link for transferring video, audio and other files between two devices.

IEEE 1394 (firewire) refers to the IEEE (Institute of Electrical and Electronics Engineers) digital connectivity standard commonly referred to as Firewire.

This type of interface is becoming ever more popular, some common devices using the IEEE 1394 interface are digital video cameras, hard drives and other storage devices, it offers real-time, bi-directional, fast data transfer along with Plug and Play compatibility for ease of use.

Firewire is the registered trademark of Apple's IEEE 1394 digital connection.

Installation - Install

This refers to loading programs onto a computer through the use of Diskettes, CD ROMs or other types of data transfer. A program typically needs to be installed before it can be run, once installed it is normally stored on the hard disk of a machine. When installing software you may be asked to restart your machine before using the software, this is to enable the software to update your computers registry so your operating system knows the program is installed and any file extensions/resources can be assigned.

Interface - Interfacing

Refers to the connection between two computer components and/or a computer and its peripherals, printers, scanners, etc. There are different types of interfaces all with their own qualities, for example a serial interface (commonly used in commmunications) allows data to be sent sequentially down the same line. A parallel interface works in a simlar way but is capable of sending numerous amounts of data at a time. A recent adaption of interfacing is the USB interface which has made connecting peripherals to a system easier.

IP Address - Internet Protocol

This is a unique number split into 4 parts separated by full stops, every computer connected to the internet has an IP address, a typical IP address looks like this 192.168.0.1.

IRQ - Interrupt ReQuest

This can be thought of as a 'channel' that devices in your PC use when they want the processors attention, ie when you move the mouse or press a key, it is important that the IRQ settings in your machine are set correctly otherwise it can cause devices to conflict with each other.

ISDN - Integrated Services Digital Network

This allows the use of data transfer and voice communication simultaneously on the same phone line, it also offers faster data transfer than it's analogue counterpart but not as fast as ADSL.

ISP - Internet Service Provider

ISP refers to a company which provides Internet services.

Most ISPs also provide web-mail (online email access) which allows you to access your emails from any computer.