![Some General Information about Information Technologies.<br />A B C D E F G H I J K L M N O P Q R S T U V W X Y Z<br />A<br />ADSLSometimes referred to as Broadband, ADSL is a connection available from Telecom companies using existing lines with fast download & upload speeds.<br />AGPAn interface developed by Intel which allows a graphics card to access memory directly which along with the wider bandwidth helps improve graphics performance. AGP has now come to replace a lot of PCI video cards due to its superior performance, most modern motherboards have an AGP slot as standard. Some motherboards come with an AGP graphics card built-in. You will see AGP cards advertised with different specifications, including throughput (bandwidth), here is a summary of the throughput they refer to:<br />1X - 266MBps2X - 533MBps4X - 1.07GBps8X - 2.1GBps<br />Obviously the higher the throughput the better, although nowadays most video cards run at 8X.<br />ATARefers to a hard drive interface standard first approved in 1994 by ANSI (American National Standards Institute).<br />AttachmentThis is the name given to a file that is sent along with an email. An email attachment can be any type of file, including images (photos), videos, mp3s, documents, zipped files/folders, and more.<br />AVIA multimedia file type, the audio and video elements are interleaved in alternate segments within the AVI file. This has become a very popular format on the Internet for video distribution due to the fast download times and reasonable quality reproduction.<br />B<br />BandwidthBandwidth refers to the capacity of a communications line/channel to transmit/receive information and is measured in bits, bytes, kilobytes, megabytes and gigabytes.<br />BinaryBinary is a system used by digital devices like computers, cd players etc. It is a sequence of 1s and 0s which relate to on and off electrical pulses and can only have 2 states on and off unlike analogue systems which can have varying states. These 1s and 0s are commonly referred to as a bit (Binary Digit). Mathematically binary is Base 2 unlike our counting system (decimal) which is Base 10.<br />BIOS - Basic Input Output SystemThe BIOS is a collection of commands usually stored in a ROM chip, which allows a CPU to communicate with the connected devices in a PC or other digital system.<br />BitmapThis is a common graphic format used by computers, it can be likened to a map of bits (hence the name) the graphic/picture is made up of a number of individual dots (bits) to form an image. The file extension for these type of files is .bmp, these can get very large in file-size (i.e. kilobytes) and if storage space is a factor then it is best to convert the image into a more compressed format such as JPEG.<br />BLOG - weB LOGA BLOG refers to a private webpage which is published by either an individual or a group of individuals. BLOGS are commonly personal journals/diaries and are used to comment on all sorts of topics depending on the interests of the blogger (author).<br />Bluetooth Wireless TechnologyBluetooth refers to a wireless technology which allows digital devices to easily transfer files at high speed, Bluetooth is common in many portable devices such as laptops, PDAs and mobile phones. For more detailed information please see below.<br />BrowserThis is the program you use to surf the internet. There are several internet browsers available, some of the most popular are Internet Explorer, Firefox, Netscape Navigator and Opera. Different browsers render web pages slightly differently, for example some sites may require a certain browser to function correctly and some sites may not function at all with some browsers.<br />C<br />Cache - CachedPronounced \"
Cash\"
this usually comes in two forms, either disk cache or memory cache, the former being a space normally on a hard disk set aside by the computer/software to store information it thinks it will need again, for instance browsers use disk cache to store information from websites such as pictures and alike, this reduces the need for the modem to keep downloading the same data each time you visit a webpage. The latter can either utilize normal memory or special memory which has a faster access time that is used by the system to store information that is used frequently, it can also 'guess' what information the user may require next and loads this into the cache memory for faster access.<br />CMOS - Complimentary Metal Oxide SemiconductorWhen in the context of computing CMOS refers to a chip that stores information about your PC including the time, date and configuration data, this technology is used due to the low power consumption. The CMOS device is backed up by a battery to retain the information when the system is switched off.<br />CODEC - COmpressor / DECompressorCODEC in the context of computing is an acronym for COmpressor/DECompressor and refers to a small piece of code (program) which is used to compress and decompress data, you will normally come across these when using Audio and Video. You may be prompted during internet use to download a CODEC if you visit a site that requires a certain CODEC not already installed on your PC.<br />Cookie - CookiesCookies are small text files that are placed on your computer by websites for various different reasons. For instance Yahoo use cookies for reasons such as storing your preferences for Yahoo related services, and to access certain information when you sign in to a personalized service such as My Yahoo. Other websites will often use cookies for identifying purposes, demographic statistics and also when you are shopping online to remember what you have in your basket.<br />CPU - Central Processing UnitThe CPU (processor) is one of the most important components in a computer, it can be likened to the brain of the system. There are 2 main PC CPU manufacturers, Intel and AMD.<br />Cursor - Flashing CursorThis refers to the small blinking vertical or horizontal line which shows the position on the screen where text will appear the next time you type a character on the keyboard. The cursor can be moved around the screen using the cursor (arrow) keys or alternatively using a mouse.<br />D<br />Data - Process DataData is used to describe information that is stored and/or processed digitally. Data can refer to (basically) anything, such as word processor documents, images, music, games, etc, although in it's purest form in a digital system it is simply bits stored/processed in a certain way.<br />Database - Relational DatabaseDatabase refers to a file that is used to store information in a format that is easily retrieved and manipulated. The most common database files are made up of tables, fields and records. These are referred to as a relational database.<br />Defragmentation - FragmentationDefragmentation is the term given to the process of scanning the file system and rejoining the split files back into consecutive pieces. The process of defragmenting can be time consuming, but it is one of the easiest ways to increase the performance of your PC, the frequency of which a PC should be defragmented will directly depend on the amount of usage. Fragmentation is caused when an operating system breaks a file into pieces because there is not enough space on the storage device where the file was originally saved. One example of this would be where a file was originally saved, then modified causing the file to be larger in physical space than first anticipated, the operating system will then break the file into 2 or more pieces and store them in different parts of the storage area. The system would then keep a record of where the different parts of the file are stored, this is achieved through the use of a File Allocation Table (FAT) or similar file system such as NTFS. Then, when the operating system requires the file again, it will query the file system (FAT/NTFS/or other) to find out where the different parts of the file are located on the partition (drive).<br />Desktop - Mac DesktopDesktop refers to the main screen area of the Mac operating system (see below).<br />DDR - Double Data RateDDR refers to a specification of SDRAM memory, DDR can transfer data at double the rate of normal SDRAM. It achieves this by transferring data twice per clock cycle, once on the rising edge and once on the falling edge of the cycle.<br />DIMM - Dual Inline Memory ModuleDIMM refers to a type of memory module commonly used in modern PCs and Laptops. DIMMS have a 64-bit data path and are widely used in PCs with 64-bit processors as they don't need to be doubled up unlike SIMMS. The dual inline part refers to the way the chips are mounted on the module. They come in either a 144 pin or 168 pin package, the 144 pin module is commonly used in laptops and the 168 pin modules are used in most modern PC motherboards.<br />DirectoryA directory and folder are exactly the same thing, windows refers to them as folders but you will often come across them being called directories. Directories/folders allow information to be stored in your computer in a more convenient way making it easier to organize your files. Directories/folders can be created, renamed and deleted much like files, it is good practice to create these directories/folders and keep your files in them as this helps keep your hard drive organized.<br />Disk Drive - DrivesRefers to a device that is used to read and write data using read/write heads from magnetic disk like devices. Floppy disk drive refers to the device at the front of the computer, floppy disks are inexpensive and are very handy for keeping small files backed up.<br />DDL - Dynamic Link LibraryDLL refers to a type of file that is stored either locally or remotely. It is a collection of commands and/or data which can be shared by different programs on the same platform.<br />DMA - Direct Memory AccessDLL refers to a type of file that is stored either locally or remotely. It is a collection of commands and/or data which can be shared by different programs on the same platform.This can be thought of as a channel or line that is used by devices in the computer to access the memory (RAM) without having to utilize the CPU. It works by allowing the I/O controller that has been previously instructed to transfer a block of data (the size depending on the system) to or from the memory to temporarily control the memory itself by returning the memory address of the data, it can control the memory for as many clock cycles as is required for the process. This system can significantly reduce the workload on the CPU.<br />DNS - Domain Name ServerA domain name is a unique name that is used to identify and locate computers on a network (including the internet), it can be used for websites and/or email addresses. For instance this website's domain name is www.helpwithpcs.com. All machines connected to the internet have their own IP Address, domain names are just an easier way to access a certain machine, for instance if you had to remember IP Addresses instead of domain names it would be cumbersome.<br />DOS - Disk Operating SystemThis is a system that software uses to utilize the disk drives in your computer. See also MS-DOS. IBM® first created DOS® for the series 700 computers years ago, then Microsoft® developed their own version called MS-DOS®, over the years DOS has become outdated due to its limited capabilities, although Windows® still shipped with MS-DOS® until the recent XP version.<br />Dot PitchThis is normally used to describe a monitor's performance, it refers to the distance between the holes of the shadow mask in a CRT display, it can also refer to the distance between each pixel on a color screen, it is measured in millimeters. Generally the smaller the measurement the better the display.<br />Download - DownloadingThis is used to describe when a file is transferred from a remote machine to a local machine using a communications link, for instance when you download a file from a website you are transferring the data from the host to your machine (client). The speed of the download will depend on what connection there is between the two machines and the size of the file to be transferred.<br />DPI - Dots Per InchThis is a measurement commonly used to describe the quality of printers and scanners, it refers to how many pixels per square inch that it is able to print/scan. The higher the DPI the smoother the quality of the image will be when either printed or scanned.<br />DRAM - Dynamic Random Access MemoryA type of memory (RAM) widely used in today's PCs. DRAM works differently to SDRAM as it needs to be refreshed to continue holding the data, this means a slight loss of speed as the memory refreshes itself with a pulse of current to each of its cells.<br />Driver - Device DriverThis is a program that is written specifically to control a certain piece of hardware such as a soundcard, modem, graphics card, printer, scanner etc. Each manufacturer supplies drivers for their specific products, these drivers are often updated with time so it is a good idea to keep your drivers current. To find specific drivers for any of your devices it is best to start at the manufacturer's website as they normally have updated drivers in their respective support pages.<br />E<br />ECC - Error Correcting CodeRefers to a type of Memory (RAM) that automatically checks for errors as the data is passed through.<br />EIDE Enhanced Integrated Drive ElectronicsEIDE refers to an interface standard developed by Western Digital, since around the end of 1994 EIDE controllers have been widely used in the PC industry surpassing the earlier IDE standard due to its faster data transfer rates. The interface controls storage devices like hard drives, CD ROM drives, and CD Writers.<br />EmailThis is a system used by computers to send and receive messages over the internet, when you send an email and likewise when someone sends you an email, the message will remain on the server (your email providers computer) until it is read and deleted, in other words you don't have to be connected to the internet to read an email unlike chat. For more information click here to see our beginner's guide.<br />EPROM - Erasable Programmable Read Only MemoryRefers to a type of ROM that can be erased using an ultra violet light and then reprogrammed using a PROM Programmer. These chips have a small transparent area on the top, this is where the UV light is directed to clear the contents, they come in various different packages which make them very versatile. The ROM will retain the data until it is exposed again to an ultra violet light, it is normal practice to cover the small transparent area to avoid any potential data loss.<br />Ethernet - NetworkingRefers to a standard of the LAN system, Ethernet supports up to 10Mbps per second transfer, a newer implementation of the Ethernet specification 100 Base-T supports up to 100Mbps. The latest standard (Gigabit Ethernet) can support up to 1000Mbps (1 Gigabit). Ethernets are common place in offices where file/device sharing is required.<br />F<br />FAT - File Allocation TableFAT (File Allocation Table) refers to a data table that holds information about how and where files are stored on any one partition (for simplicity think of a partition as all the files on your hard drive).For example, a single file on your hard drive may not be stored in one place, the file could be split up and stored in several different (physical) places (this is called fragmentation), the FAT keeps a record of where the different parts of the file are stored.<br />FirewallRefers to a security program which protects your computer from un-authorised access through a network and/or the Internet. These are very important especially if your computer is connected directly to the Internet for long periods of time.<br />Firewall - iLink - IEEE1394A 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. Apple inc, Sony Corp and a few others helped to develop the IEEE 1394 standard. 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.<br />IEEE 1394/Firewire characteristics:<br />IEEE 1394a - Firewire 400- Data Throughput: 400Mbps- Maximum Cable Length: 4.5 MetersIEEE 1394b - Firewire 800- Data Throughput: 800Mbps- Maximum Cable Length: 100 MetersFirewire® - Firewire is the registered trademark of Apple's IEEE 1394 digital connection.iLink® - iLink is the registered trademark of Sony's IEEE 1394 digital connection.<br />FolderFolder and directory are exactly the same thing, windows refers to them as folders but you will often come across them being called directories. Directories/folders allow information to be stored in your computer in a more convenient way making it easier to organize your files. Directories/folders can be created, renamed and deleted much like files, it is good practice to create these directories/folders and keep your files in them as this helps keep your hard drive organized.<br />FreewareThis is software that is free, and as long as you can put up with the occasional advert there are some programs/utilities out there that are very useful.<br />FTP - File Transfer ProtocolOne of the TCP/IP protocols used for transferring files across TCP/IP connections. The protocol manages the physical transfer of the file along with the representation of the file on both machines involved in the transfer. To upload or download files via FTP you need an FTP program such as Cute FTP.<br />G<br />GHzGigahertz 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.<br />GIF - Graphics Interchange FormatThe 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.<br />Gigabyte - GBThis 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, ie230.<br />Graphics CardA Graphics Card also known as a Video Card is an internal device which controls and produces the display on your screen.<br />GUI - Graphical User InterfaceThis 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.<br />H<br />Hard Disk - Hard DriveA Hard Disk (Hard Disk Drive) is your computer's main storage device. It is where you would normally keep your operating system, programs and files.<br />Hardware - ComponentsThis 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.<br />Host - HostingHost 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.<br />HTML - HyperText Mark-up LanguageHTML is a markup language used to create HTML documents. HTML documents allow plain text to be formatted (bold, italic, etc), as well as being able to specify hyperlinks, images and more.<br />HTTP - HTTPS - HyperText Transfer ProtocolHTTP is a communication protocol used on the internet to allow the communication of 2 computers (devices). HTTPS is a secure adaptation of HTTP, which you will find in common use on secure areas when visiting websites.<br />Hub - Network Hub [Concentrator / Repeater Hub]A Network hub is a device which enables more than one computer (host) to interconnect on a network. They are widely used for creating home, office and other networks.<br />I<br />IDE - Integrated Drive Electronics | ATA - Advanced Technology AttachmentIDE (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.<br />Installation - InstallThis 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.<br />Interface - InterfacingRefers 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 communications) allows data to be sent sequentially down the same line. A parallel interface works in a similar 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.<br />Internet - TCP/IPRefers to a worldwide network of computer systems all using the TCP/IP network protocols. Commonly refers to the world wide web.<br />IP Address - Internet ProtocolThis 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 192.168.1.0.<br />IRQ - Interrupt ReQuestThis 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.<br />ISDN - Integrated Services Digital NetworkThis 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.<br />ISP - Internet Service ProviderISP refers to a company which provides Internet services such as AOL, typical ISPs provide:- A Dial-up server with which to connect to the internet along with a number, username and password.- An Email address.- A POP Server through which to receive emails.- An SMTP Server through which to send emails.<br />Most ISPs also provide web-mail (online email access) which allows you to access your emails from any computer.<br />J<br />JavaJava 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 byte code and can then be run by Java interpreters and runtime environments (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 environment, for example a chat applet can be downloaded and executed within the run time environment integrated into your web browser (Netscape Navigator, Internet explorer, etc).<br />JavaScript - Scripting LanguageJavaScript 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.<br />JPEG - Joint Photographics Experts GroupThis 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 colors 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.<br />K<br />Kbps = kilobits per secondA 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.<br />KernelKernel 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.<br />Keyboard Shortcuts - HotkeysKeyboard 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.<br />Kilobyte - KBA measurement used in digital systems to describe storage capacity, 1 Kilobyte is equal to 1024 (210) Bytes in digital systems.<br />L<br />LAN - Local Area NetworkThese 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.<br />LCD - Liquid Crystal DisplayLCD 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.<br />LPT - Line Printing TerminalThe 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).<br />M<br />Megabyte - MBThis is a measurement used in digital systems such as PCs to describe storage capacity (usually RAM, Hard Drive capacity is mostly stated in Gigabytes these days). Mathematically one Megabyte is 220 (1,048,576) One megabyte is equal to 1024 Kilobytes, so a memory module with a capacity of 256MB can store 268,435,456 Bytes.<br />MHz - MegahertzA frequency measurement, refers to millions of cycles per second, for example a processor running at 500 MHz can handle 500 Million cycles per second. See also GHz, 1 MHz is equal to 1,000,000 Hz. Hertz is named after Physicist Heinrich Hertz.<br />MIDI - Musical Instrument Digital InterfaceRefers to a widely used interface that allows musical instruments such as electric keyboards to be controlled and interacted with by a computer. Most modern soundcards come with some sort of MIDI interface built-in.<br />MIME - Multipurpose Internet Mail ExtensionsA system used for the ASCII (American Standard for information interchange) encoding of binary data for transfer via email on the internet. MIME codes are also used to let the browser know what type of file to expect when it has requested it. For instance, if a browser requests a GIF file, then the host will send in the CONTENT TYPE HEADER the MIME string to indicate that the file is indeed a GIF file and should be processed accordingly.<br />MODEM - MOdulator DEModulatorA communications device used to connect to a network such as the internet. Modems come in various different forms, the most common is the internal modem which uses a PCI interface to connect to the motherboard. Some motherboards come with modems built-in.<br />MotherboardA motherboard (mainboard) is the main circuit board within a PC, most modern motherboards come with the following features:- A processor slot (type will depend on the board specifications)- Memory banks- AGP slot- PCI slots- IDE interface- USB portsThese are just some of the features that a motherboard may have as standard, some motherboards come with integrated components such as a sound card, graphics, modem, NIC (Network Interface Card) and more.<br />All the components inside your PC connect to the motherboard in one way or another, a few examples:- Memory banks are used for RAM modules.- PCI slots are used to provide connectivity for PCI cards such as modems and sound cards.- AGP slots are used for graphics accelerators.- IDE interfaces are used to connect and control IDE devices such as hard drives and CD-ROM drives.<br />Mouse - Pointing DeviceA mouse is a pointing device used to interact with a PC, there are a few different types of mouse available:- Serial Mouse - This is a mouse with a serial connector, it requires a free serial port on your PC.- USB Mouse - This type of mouse has a USB connector and requires a free USB port.- Cordless Mouse - A cordless mouse (as the name suggests) has no cable, this type of mouse utilizes batteries for its power supply.- Optical Mouse - An optical mouse utilizes optical electronics to track the mouse's position and movement, they are preferred over standard mechanical mice as they tend to be more reliable and require less maintenance.<br />MP3 - MPeg-1 audio layer 3Refers to an audio file which has been compressed using the MPEG (see below) compression standard. Using this standard greatly reduces the physical size of the audio file with little or no loss of sound quality.<br />MPEG - Motion Picture Experts GroupA compression standard used for compressing Video and Audio files to a smaller physical size, the compression is achieved by not recording every frame but only the changes between the frames. Motion Picture Experts Group is the name given to the group of people responsible for inventing the standard.<br />MPEG files have either the .mpeg or .mpg file extension and are a very common format due to the high compression.<br />The main implementations of MPEG are:- MPEG-1 - video resolution of 352x240px at 30 frames per second- MPEG-2 - video resolution of up to 1280x720 at 60 frames per secondthese are the most common and the ones you are likely to come across.<br />MS-DOS MicroSoft® Disk operating SystemThis is the system that Windows® based machines use to access and maintain storage devices.<br />N<br />Network - NetworkingA system to allow 2 or more computers to connect to each other and share files or peripherals. Typical types of networks are LAN, WAN and on a wider scale the Internet.<br />Network Switch - SwitchA switch (switching hub) is a network device which is used to interconnect computers and/or devices on a network. They are relatively inexpensive and offer better performance than a hub.<br />NIC - Network Interface CardAn NIC (network interface card) is an expansion card that provides connectivity between a PC and a network such as a LAN, NICs are sometimes called Ethernet adapters. Network Interface Cards (NICs) can be internal or external add-ons and come with various specifications, one of which is transfer rate although most modern network interface cards support up to 100Mbps, and the more expensive Gigabit Ethernet cards supporting up to 1000Mbps.<br />O<br />OEM Hardwareis the term given to a manufacturer that buys hardware from another source, and implements it into their own design. See below for more information. OEM Software means that the software is sold only with a certain piece of hardware and/or the software manufacturer provides no technical support. See below for more information.<br />Online - OfflineOnline - A term given to a person/computer that is connected to a network. Offline - A term given to a person/computer that is not connected to a network.<br />Operating System - OSRefers to the main software of a computer system for instance Windows®, all installed programs run under the control of the operating system.<br />P<br />Parallel Port - ECP - EPP - Parallel InterfaceParallel port/interface refers to a standard 25 pin (D25) connector found on most (if not all) PCs, commonly used for connecting a printer. A standard parallel port transmits 8 data bits at a time, as opposed to a serial port which transmits data one bit at a time.<br />PCMCIA - Personal Computer Memory Card International AssociationA body including hardware and chip manufacturers, system integrators and software houses set up in 1989. A PCMCIA card is a credit card sized device that is used to upgrade memory or add communication devices to notebooks and laptop computers.<br />PDA - Personal Digital AssistantA (Personal Digital Assistant) refers to a hand-held device that incorporates several handy features. PDAs often include an address book, calendar, contacts list, and a memo feature.<br />PDF (Portable Document Format)PDF refers to a type of document (PDF Document) format, which is widely used on the internet. You need software (freely available) called Adobe Reader, in order to view PDF documents.<br />PIXEL - Picture ElementRefers to individual 'bits' of data that form an image, also refers to screen resolution, for example 800x600 is 800 pixels wide and 600 pixels high, 1024x768 is 1024 pixels wide and 768 pixels high.<br />PnP - Plug and PlayPlug and Play was developed by Intel® and Microsoft® and was designed to simplify the installation of new hardware. Windows 95 was the first operating system to include Plug and Play technology. Plug and Play compatible devices communicate with the operating system allowing automated configuration, when a Plug and Play device is connected and the machine re-booted (if not USB) the operating system will acknowledge the new hardware and prompt you for the installation disk that came with the hardware. The device drivers should then be automatically installed.<br />POP - Post Office ProtocolA POP (Post Office Protocol) server allows you to receive your mail through an email client program such as Outlook or Netscape Messenger, this allows you to just connect to retrieve your mail from your email provider, and then you can read your mail offline and can reduce your online time.<br />Port - PortsA communications port on a computer for example the serial port, parallel port, USB port or a port on a server. Different ports have different characteristics and data transfer capabilities, see also Interface.<br />Protocol - ProtocolsA standard set of software instructions which allow a computer to communicate with another and/or other devices.<br />PSU - Power Supply UnitThis regulates and distributes the power to the components inside your PC. The standard now is ATX which can be accessed by the motherboard/software to enable the PSU to be \"
put to sleep\"
, conserve energy or shut down.<br />Q<br />R<br />RAID - Redundant Array of Independent DisksRAID refers to a hard disk technology which can be used to speed up data transfer and/or provide disk redundancy through disk system fault tolerance. RAID provides these features by utilizing more than one hard disk at a time, there are several variations of a RAID configuration referred to as levels. Each of these levels provide different performance and/or fault tolerance benefits. RAID configurations are commonly found in data critical applications.<br />RAM - Random Access MemoryThis is the main memory in your computer, this is where the computer stores the data it needs when you are using a program. RAM gets its name from the ability to allow the system to access any data stored in the memory in any location at any time. This memory is often referred to as Volatile (power dependent). i.e. when the power is isolated the data is lost. RAM comes in many different packages and there are many different types of RAM all designed to be compatible with a certain system.<br />Resolution - High ResolutionWhen referring to a monitor this measurement depicts the amount of horizontal and vertical pixels i.e. 1024x768, when referring to a printer/scanner it depicts the DPI.<br />ROM - Read Only MemoryROM refers to a type of memory storage which is non-volatile (not power dependant). It cannot be changed using normal methods i.e. written to like RAM. ROMS are widely used for any application that requires data to be stored permanently and/or without a constant supply of power. The BIOS in a digital system is typically ROM based.<br />Router – Network RouterA router is placed at a junction between two or more networks/segments, each network/segment can be using a different topology or protocol. The router will intercept and forward any data packets passing through, most routers can be set up to block certain types of data packets which can be useful for security reasons. The destination address of the data packet needs to be included within the header information, routers don't propagate broadcasts/multicasts. The router will then decide the best route for transferring the data packet to its destination by interrogating a routing table which is either static or dynamically generated.<br />S<br />SATARefers to an interface type used for data storage devices. The SATA interconnect is a serial implementation of the parallel Ultra ATA interface used to connect storage devices such as hard drives & optical drives to a PC's motherboard (host system). The SATA technology starts at a data transfer rate of 150MB/sec, with plans already in place to take it up to 600MB/sec. Some of the advantages of SATA over Ultra ATA:- Cables are easier to work with.- CRC error checking on all data (and control information).- Hot-swap capability.- Less crosstalk due to cable design.<br />SCSI - Small Computer System InterfaceA standard for connecting multiple devices such as hard drives, cd roms, floppy drives, etc, it enables the connection of more devices than its counterpart IDE and normally faster, but the drives tend to carry a bigger price tag.<br />SCSI was originally developed by Shugart Associates and was originally called SASI (Shugart Associates System Interface) before it became standardized.<br />SDRAM - Synchronous Dynamic Random Access MemoryRefers to a type of memory (DRAM) that can synchronize itself with the processor's bus speed, and can run at much higher speeds than it's EDO counterpart.<br />Sector, Track and ClusterA Sector in the context of computing refers to a small area of a storage device, for example a hard disk drive.<br />Serial Port - PortsCommunications port which connects the computer to various peripherals including modems. A serial port transmits data sequentially (one bit at a time) as opposed to parallel ports which transmit 8 bits at a time.<br />Server – Server SoftwareA server is a computer running software that allows it to control the sharing of resources between many computers. Servers are often dedicated to one task depending on what type of server software they are running, below is a summation of a few common server applications: HTTP Server - An HTTP (HyperText Transfer Protocol) server (web server) is typically connected to the internet with a high speed connection and will respond to requests from computers running client software (like a browser) requiring specific data (commonly a web page). This type of server is common to the internet. FTP Server - An FTP (File Transfer Protocol) server is used to transfer files over a network (WAN, LAN or the internet) using the FTP protocol. Mail Server - A mail server stores and transfers (e)mail over a network (WAN, LAN or the internet). Chat Server - A chat server allows its users to transfer real time text between two or more computers, for more on chat click here. Database Server - A database server allows its users to access its database via a network (WAN, LAN or the internet) and depending on permissions, read, delete or alter the contents of its database. This type of server is common place in an office environment. Proxy Server - A proxy server (as the name suggests) typically sits between the client and the main server, it is used to filter data and enable connections to be shared. For example if you are in the UK and you connect to a website that is hosted in the US then the data you send/receive will pass through one or more proxy servers.<br />Shareware - softwareA type of software that is not commercial and normally requires a registration payment to the author, there is normally a trial period.<br />SMTP - Simple Mail Transfer ProtocolAn SMTP server allows you to send emails which have been written within your email client program such as Outlook or Netscape Messenger, this allows you to write your emails offline and then connect for a few seconds to send them. Most email providers supply an SMTP server through which you can send your emails.<br />Software - ProgramsA term given to the programs that a computer executes. A typical example of software would be a word processor or an accounts package.<br />Soundcard - Sound CardThis is an internal device which controls and produces any sounds including music that your PC makes. Sound cards come with various specifications, for example some have more inputs/outputs than others allowing for 5.1 surround sound etc, others have a higher sampling frequency to give better sound recording. Sound cards can also come built-in to motherboards (mainboards), although the built-in cards are usually sufficient for most uses they can be lacking in quality and features if you intend to record or create digital music or sounds.<br />SPAM - SPAM EmailSPAM refers to unsolicited commercial email. The SPAM problem is one that nearly every email user will experience, there are however, ways to decrease the amount of SPAM you receive.<br />SSL - Secure Sockets LayerA protocol developed by Netscape to transfer information via the Internet securely. Web sites use this encryption to allow users to enter credit card numbers and other confidential information, normally you will see the padlock in your browser lock and the URL will begin HTTPS as opposed to HTTP.<br />SVGA - Super Video Graphics ArrayA standard for monitors and graphic cards developed by VESA (Video Electronics Standards Association) which supports resolutions of up to 800x600 Pixels and up to 16 Million Colors.<br />T<br />Terabyte - TBThis is commonly used to describe the capacity of a digital system. A Terabyte is 1,099,511,627,776 bytes (2 to the 40th power).<br />TCP/IP - Transmission Control Protocol / Internet ProtocolA collection of protocols (rules) that depict how data is transferred across networks between computer systems.<br />TIFF - Tagged Image File FormatTIFF (Tagged Image File Format) refers to a type of image format developed by Aldus and Microsoft that is commonly used within computing. TIFF files are basically Bitmap images, they are not restricted in resolution and can be black and white, grey scale or full color.<br />TFT - Thin Film TransistorA type of LCD (Liquid Crystal Display) used in the screen of laptops/notebooks, with 1 to 4 transistors defining one pixel on-screen.<br />U<br />V<br />V90 - V.90A standard used by all modern 56k modems.<br />Virus - VirusesA program that runs on your computer without your knowledge and can cause damage to your files. It usually attaches itself to other programs, a common way to receive a virus is through an attachment via email. Virus protection is extremely important and can save a lot of problems in the future.<br />VPN - Virtual Private NetworkA VPN (Virtual Private Network) refers to a secure network connection that uses the internet to transmit data. The data is typically encrypted using different tunneling protocols such as L2TP(Layer 2 Tunneling Protocol) and PPTP (Point to Point Tunneling Protocol) in which the encrypted data is encapsulated in Internet wrappers before it is transmitted. When the data is received at its destination the Internet wrapper is stripped off and the data decrypted. Typical uses of VPNs would be to create a private WAN without the need to lease dedicated lines or provide travelling employees with a secure connection to company data.<br />W<br />Wait StateThis refers to when a processor or other component has to rest in between clock cycles due to a slower component such as memory. See also zero wait state.<br />WAN - Wide Area NetworkAs the name suggests it is a network of computers over a wide geographical area.<br />WAP - Wireless Application ProtocolWAP (wireless application protocol) refers to a wireless transfer protocol developed by Ericsson, Motorola, Nokia and Unwired Planet. The WAP protocol allows users of handheld devices such as mobile phones to access data and view locally. Some of the wireless networks supported by WAP are listed below:- DataTAC- DECT- CDMA- CDPD- FLEX- GSM- iDEN- Mobitex- PDC- PHS- ReFLEX- TDMAMost WAP devices can support HTML, XML, WML and WMLScript All operating systems can support the WAP specification, although there are operating systems that have been designed with WAP in mind, such as for PDA's (Windows CE and PalmOS are 2 examples).<br />WAV - WAV audio fileAn audio file format developed jointly by IBM and Microsoft, WAV audio files have a file extension of .wav and are commonly used within the Windows environment.<br />WIFIWI-FI refers to a type of wireless technology which allows users to connect to a local network without the need for cables, also known as a WLAN (Wireless Local Area Network).<br />WLANrefers 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.<br />WWW - World Wide WebDescribes the internet as a whole, millions of computers all over the world connected via phone lines and modems.<br />X<br />Y<br />Z<br />Zero Wait StateRefers to a system that allows the processor to work at full clock speed regardless of the clock speed of the memory (RAM).<br />ZIF - Zero Insertion ForceRefers to a type of chip (processor) socket with which an arm or release device is used to lock the chip in place.<br />Below we have compiled a useful directory of Mac Keyboard Shortcuts. <br />Startup<br />KeystrokeDescriptionPress X during startupForce Mac OS X startupPress Option-Command-Shift-Delete during startupBypass primary startup volume and seek a different startup volume (such as a CD or external disk)Press C during startupStart up from a CD that has a system folderPress N during startupAttempt to start up from a compatible network server (NetBoot)Press T during startupStart up in FireWire Target Disk modePress Shift during startupStart up in Safe Boot mode and temporarily disable login items and non-essential kernel extension files (Mac OS X 10.2 and later)Press Command-V during startupStart up in Verbose modePress Command-S during startupStart up in Single-User mode<br />Finder Window<br />KeystrokeDescriptionCommand-WClose WindowOption-Command-WClose All WindowsCommand-Right ArrowExpand Folder (list view)Option-Command-Right ArrowExpand Folder and Nested Subfolders (list view)Command-Left ArrowCollapse Folder (list view)Option-Command-Up ArrowOpen parent folder and close current window(Assigned in Keyboard & Mouse Preferences)Show Package Contents (of selected file in Mac OS X 10.5 or later only). To create this contextual menu shortcut, open Keyboard & Mouse preferences in Mac OS X 10.5, click Keyboard Shortcuts, click the \"
+\"
button, choose Finder.app as the Application, and type \"
Show Package Contents\"
(exactly), and set whichever shortcut you want, such as Command-Control-S.<br />Menu Commands<br />KeystrokeDescriptionShift-Command-QApple Menu > Log outShift-Option-Command-QApple Menu > Log out immediatelyShift-Command-DeleteFinder Menu > Empty TrashOption-Shift-Command-DeleteFinder Menu > Empty Trash without dialogCommand-HFinder Menu > Hide FinderOption-Command-HFinder Menu > Hide OthersCommand-NFile Menu > New Finder WindowShift-Command-NFile Menu > New FolderCommand-OFile Menu > OpenCommand-SFile Menu > SaveShift-Command-SFile Menu > Save AsCommand-PFile Menu > PrintCommand-WFile Menu > Close WindowOption-Command-WFile Menu > Close ALl WindowsCommand-IFile Menu > Get InfoOption-Command-IFile Menu > Show Attributes InspectorCommand-DFile Menu > DuplicateCommand-LFile Menu > Make AliasCommand-RFile Menu > Show OriginalCommand-TFile Menu > Add to Favourites (Mac OS X 10.2.8 or earlier), Add to Sidebar (Mac OS X 10.3 or later - use Shift-Command-T for Add to Favourites)Command-DeleteFile Menu > Move to TrashCommand-EFile Menu > EjectCommand-FFile Menu > FindCommand-ZEdit Menu > UndoCommand-XEdit Menu > CutCommand-CEdit Menu > CopyCommand-VEdit Menu > PasteCommand-AEdit Menu > Select AllCommand-1View Menu > View as IconsCommand-2View Menu > View as ListCommand-3View Menu > View as ColumnsCommand-BView Menu > Hide ToolbarCommand-JView Menu > Show View OptionsCommand-[Go Menu > BackCommand-]Go Menu > ForwardShift-Command-CGo Menu > ComputerShift-Command-HGo Menu > HomeShift-Command-IGo Menu > iDiskShift-Command-AGo Menu > ApplicationsShift-Command-FGo Menu > FavoritesShift-Command-GGo Menu > Go to FolderCommand-KGo Menu > Connect to ServerCommand-MWindow Menu > Minimize WindowOption-Command-MWindow Menu > Minimize All WindowsCommand-?Help Menu > Open Mac HelpCommand-SpaceOpen Spotlight (Mac OS X 10.4 or later)Command-escFront Row - Activates Front Row for certain Apple computers<br />Universal Access and VoiceOver<br />KeystrokeDescriptionOption-Command-8Turn on ZoomOption-Command-+(plus)Zoom InOption-Command--(minus)Zoom OutControl-Option-Command-8Switch to White on BlackControl-F1Trun on Full Keyboard Access. When Full Keyboard Access is turned on you can use the key combinations listed below from the Finder.Control-F2Full Keyboard Access > Highlight MenuControl-F3Full Keyboard Access > Highlight DockControl-F4Full Keyboard Access > Highlight Window (active) or next window behind itControl-F5Full Keyboard Access > Highlight ToolbarControl-F6Full Keyboard Access > Highlight Utility window (paletteControl-F5 or fn-Command-F5Turn VoiceOver on or off (Mac OS X 10.4 or later)Control-Option-F8 or fn-Control-Option-F8Open VoiceOver Utility (Mac OS X 10.4 or later)Control-Option-F7 or fn-Control-Option-F7Display VoiceOver menu (Mac OS X 10.4 or later)Control-Option-; or fn-Control-Option-;Enable / Disable VoiceOver (Mac OS X 10.4 or later)<br />The Universal Access preference pane allows you to turn on Mouse Keys. When Mouse Keys is on, you can use the numeric keypad to move the mouse. If your computer doesn't have a numeric keypad, use the fn (function) key.<br />Mouse Keys<br />KeystrokeDescription8Move Up2Move Down4Move Left6Move Right1, 3, 7, and 9Move Diagonally5Press Mouse Button0Hold Mouse Button. (period on keypad)Release Mouse Button (use after pressing 0)<br />Other Commands<br />KeystrokeDescriptionOption-Command-DShow/Hide DockCommand-TabSwitch ApplicationTabHighlight next itemCommand-Up ArowMove up one directoryCommand-Down ArrowMove down one directoryPage Up or Control-Up ArrowMove up one pagePage Down or Control-Down ArrowMove down one pageOption-DragCopy to new locationOption-Command-DragMake alias in new locationCommand-DragMove to new location without copyingShift-Command-CShow Colors Palette in applicationCommand-TShow Font Palette in applicationCommand-Shift-3Take a picture of the screenCommand-Shift-4Take a picture of the selectionCommand-Shift-4, then press Control while selectingTake a picture of the screen, place in ClipboardCommand-Shift-4, then SpacebarTake a picture of the selected windowOption-Command-escForce QuitControl-EjectRestart, Sleep, Shutdown dialog boxControl-Command-EjectQuit all applications and restartOption-Command-Eject or Option-Command-PowerSleepCommand-click window toolbar button (upper right corner)Cycle through available views for the window's toolbar (dependent on the nature of the Finder or applciation window)Command-`Cycle through windows in application of Finer (if more than one window is open)Function-Delete (portables only e.g. PowerBook, iBook, MacBook, MacBook Pro)Forward Delete (delete the character to the right of your cursor<br />Below we have compiled a useful directory of PC Keyboard Shortcuts. <br />CTRL Commands<br />Keyboard ShortcutResult in Windows® XP - GeneralCTRL+ASelects all the items in the active windowCTRL+CCopies the item or items to the Clipboard and can be pasted using CTRL and VCTRL+FDisplays the Find all files dialog boxCTRL+GDisplays the Go to folder dialog boxCTRL+NDisplays the New dialog boxCTRL+ODisplays the Print dialog boxCTRL+PDisplays the Print dialog boxCTRL+SDisplays the Save dialog boxCTRL+VPastes the copied item or items from the ClipboardCTRL+XCuts the item or items selected to the ClipboardCTRL+ZUndoes the last actionCTRL+F4Closes the active document windowCTRL while dragging an itemCopy the selected itemCTRL+SHIFT with arrow keysHighlight a block of textCTRL+ESCDisplay the Start menuCTRL+F6Opens the next document window in the active application<br />ALT Commands<br />Keyboard ShortcutResult in Windows® XP - GeneralALT+ENTERView the properties for the selected itemALT+F4Close All WindowsALT+SPACEBAROpen the shortcut menu for the active windowALT+TABSwitch between the open itemsALT+ESCCycle through items in the order that they had been opened<br />F-Key Commands<br />Keyboard ShortcutResult in WIndows® XP - GeneralF1 keyGive help on the active window or selected itemF2 keyRename the selected itemF3 keySearch for a file or a folderF4 keyDisplay the Address bar list in My Computer or Windows ExplorerF5 keyUpdate the active windowF6 keyCycle through the screen elements in a window or on the desktopF10 keyActivate the menu bar in the active program<br />Windows Key Commands<br />Keyboard ShortcutResult in WIndows® XP - GeneralWindows LogoDisplay or hide the Start menuWindows Logo+BREAKDisplay the System Properties dialog boxWindows Logo+DDisplay the desktopWindows Logo+MMinimize all of the windowsWindows Logo+SHIFT+MRestore the minimized windowsWindows Logo+EOpen My ComputerWindows Logo+FSearch for a file or a folderCTRL+Windows Logo+FSearch for computersWindows Logo+F1Display Windows HelpWindows Logo+LLock the keyboardWindows Logo+ROpen the Run dialog boxWindows Logo+UOpen Utility Manager<br />General Keyboard Shortcuts - Dialogue Box<br />Keyboard ShortcutResult in WIndows® XP - Dialogue BoxTABMove forward through the optionsSHIFT+TABMove backward through the optionsCTRL+TABMove forward through the tabsCTRL+SHIFT+TABMove backward through the tabsALT+Underlined LetterPerform the corresponding command or select the corresponding optionENTERPerform the command for the active option or buttonSPACEBARSelect or clear the check box if the active option is a check boxF1 keyDisplay helpF4 keyDisplay the itmes in the active listArrow KeysSelect a button if the active option is a group of option buttonsBACKSPACEOpen a folder one level up if a folder is selected in the Save As or Open dialog box<br />Windows Explorer Shortcuts<br />Keyboard ShortcutResult in WIndows® XP - Windows ExplorerENDDisplay the bottom of the active windowHOMEDisplay the top of the active windowNUM LOCK+Asterisk Sign (*)Display all of the subfolders that are under the selected folderNUM LOCK+Plus Sign (+)Display the contents of the selected folderNUM LOCK+Minus Sign (-)Collapse the selected folderLEFT ARROWCollapse the current selection if it is expanded, or select the parent folderRIGHT ARROWDisplay the current selection if it is collapsed, or select the first subfolder<br />](https://image.slidesharecdn.com/generalinformationaboutinformationtechnologies-13052880764689-phpapp01-110513070311-phpapp01/85/General-Information-About-Information-Technologies-1-320.jpg)
General Information About Information Technologies
- 1. Some General Information about Information Technologies.<br />A B C D E F G H I J K L M N O P Q R S T U V W X Y Z<br />A<br />ADSLSometimes referred to as Broadband, ADSL is a connection available from Telecom companies using existing lines with fast download & upload speeds.<br />AGPAn interface developed by Intel which allows a graphics card to access memory directly which along with the wider bandwidth helps improve graphics performance. AGP has now come to replace a lot of PCI video cards due to its superior performance, most modern motherboards have an AGP slot as standard. Some motherboards come with an AGP graphics card built-in. You will see AGP cards advertised with different specifications, including throughput (bandwidth), here is a summary of the throughput they refer to:<br />1X - 266MBps2X - 533MBps4X - 1.07GBps8X - 2.1GBps<br />Obviously the higher the throughput the better, although nowadays most video cards run at 8X.<br />ATARefers to a hard drive interface standard first approved in 1994 by ANSI (American National Standards Institute).<br />AttachmentThis is the name given to a file that is sent along with an email. An email attachment can be any type of file, including images (photos), videos, mp3s, documents, zipped files/folders, and more.<br />AVIA multimedia file type, the audio and video elements are interleaved in alternate segments within the AVI file. This has become a very popular format on the Internet for video distribution due to the fast download times and reasonable quality reproduction.<br />B<br />BandwidthBandwidth refers to the capacity of a communications line/channel to transmit/receive information and is measured in bits, bytes, kilobytes, megabytes and gigabytes.<br />BinaryBinary is a system used by digital devices like computers, cd players etc. It is a sequence of 1s and 0s which relate to on and off electrical pulses and can only have 2 states on and off unlike analogue systems which can have varying states. These 1s and 0s are commonly referred to as a bit (Binary Digit). Mathematically binary is Base 2 unlike our counting system (decimal) which is Base 10.<br />BIOS - Basic Input Output SystemThe BIOS is a collection of commands usually stored in a ROM chip, which allows a CPU to communicate with the connected devices in a PC or other digital system.<br />BitmapThis is a common graphic format used by computers, it can be likened to a map of bits (hence the name) the graphic/picture is made up of a number of individual dots (bits) to form an image. The file extension for these type of files is .bmp, these can get very large in file-size (i.e. kilobytes) and if storage space is a factor then it is best to convert the image into a more compressed format such as JPEG.<br />BLOG - weB LOGA BLOG refers to a private webpage which is published by either an individual or a group of individuals. BLOGS are commonly personal journals/diaries and are used to comment on all sorts of topics depending on the interests of the blogger (author).<br />Bluetooth Wireless TechnologyBluetooth refers to a wireless technology which allows digital devices to easily transfer files at high speed, Bluetooth is common in many portable devices such as laptops, PDAs and mobile phones. For more detailed information please see below.<br />BrowserThis is the program you use to surf the internet. There are several internet browsers available, some of the most popular are Internet Explorer, Firefox, Netscape Navigator and Opera. Different browsers render web pages slightly differently, for example some sites may require a certain browser to function correctly and some sites may not function at all with some browsers.<br />C<br />Cache - CachedPronounced \" Cash\" this usually comes in two forms, either disk cache or memory cache, the former being a space normally on a hard disk set aside by the computer/software to store information it thinks it will need again, for instance browsers use disk cache to store information from websites such as pictures and alike, this reduces the need for the modem to keep downloading the same data each time you visit a webpage. The latter can either utilize normal memory or special memory which has a faster access time that is used by the system to store information that is used frequently, it can also 'guess' what information the user may require next and loads this into the cache memory for faster access.<br />CMOS - Complimentary Metal Oxide SemiconductorWhen in the context of computing CMOS refers to a chip that stores information about your PC including the time, date and configuration data, this technology is used due to the low power consumption. The CMOS device is backed up by a battery to retain the information when the system is switched off.<br />CODEC - COmpressor / DECompressorCODEC in the context of computing is an acronym for COmpressor/DECompressor and refers to a small piece of code (program) which is used to compress and decompress data, you will normally come across these when using Audio and Video. You may be prompted during internet use to download a CODEC if you visit a site that requires a certain CODEC not already installed on your PC.<br />Cookie - CookiesCookies are small text files that are placed on your computer by websites for various different reasons. For instance Yahoo use cookies for reasons such as storing your preferences for Yahoo related services, and to access certain information when you sign in to a personalized service such as My Yahoo. Other websites will often use cookies for identifying purposes, demographic statistics and also when you are shopping online to remember what you have in your basket.<br />CPU - Central Processing UnitThe CPU (processor) is one of the most important components in a computer, it can be likened to the brain of the system. There are 2 main PC CPU manufacturers, Intel and AMD.<br />Cursor - Flashing CursorThis refers to the small blinking vertical or horizontal line which shows the position on the screen where text will appear the next time you type a character on the keyboard. The cursor can be moved around the screen using the cursor (arrow) keys or alternatively using a mouse.<br />D<br />Data - Process DataData is used to describe information that is stored and/or processed digitally. Data can refer to (basically) anything, such as word processor documents, images, music, games, etc, although in it's purest form in a digital system it is simply bits stored/processed in a certain way.<br />Database - Relational DatabaseDatabase refers to a file that is used to store information in a format that is easily retrieved and manipulated. The most common database files are made up of tables, fields and records. These are referred to as a relational database.<br />Defragmentation - FragmentationDefragmentation is the term given to the process of scanning the file system and rejoining the split files back into consecutive pieces. The process of defragmenting can be time consuming, but it is one of the easiest ways to increase the performance of your PC, the frequency of which a PC should be defragmented will directly depend on the amount of usage. Fragmentation is caused when an operating system breaks a file into pieces because there is not enough space on the storage device where the file was originally saved. One example of this would be where a file was originally saved, then modified causing the file to be larger in physical space than first anticipated, the operating system will then break the file into 2 or more pieces and store them in different parts of the storage area. The system would then keep a record of where the different parts of the file are stored, this is achieved through the use of a File Allocation Table (FAT) or similar file system such as NTFS. Then, when the operating system requires the file again, it will query the file system (FAT/NTFS/or other) to find out where the different parts of the file are located on the partition (drive).<br />Desktop - Mac DesktopDesktop refers to the main screen area of the Mac operating system (see below).<br />DDR - Double Data RateDDR refers to a specification of SDRAM memory, DDR can transfer data at double the rate of normal SDRAM. It achieves this by transferring data twice per clock cycle, once on the rising edge and once on the falling edge of the cycle.<br />DIMM - Dual Inline Memory ModuleDIMM refers to a type of memory module commonly used in modern PCs and Laptops. DIMMS have a 64-bit data path and are widely used in PCs with 64-bit processors as they don't need to be doubled up unlike SIMMS. The dual inline part refers to the way the chips are mounted on the module. They come in either a 144 pin or 168 pin package, the 144 pin module is commonly used in laptops and the 168 pin modules are used in most modern PC motherboards.<br />DirectoryA directory and folder are exactly the same thing, windows refers to them as folders but you will often come across them being called directories. Directories/folders allow information to be stored in your computer in a more convenient way making it easier to organize your files. Directories/folders can be created, renamed and deleted much like files, it is good practice to create these directories/folders and keep your files in them as this helps keep your hard drive organized.<br />Disk Drive - DrivesRefers to a device that is used to read and write data using read/write heads from magnetic disk like devices. Floppy disk drive refers to the device at the front of the computer, floppy disks are inexpensive and are very handy for keeping small files backed up.<br />DDL - Dynamic Link LibraryDLL refers to a type of file that is stored either locally or remotely. It is a collection of commands and/or data which can be shared by different programs on the same platform.<br />DMA - Direct Memory AccessDLL refers to a type of file that is stored either locally or remotely. It is a collection of commands and/or data which can be shared by different programs on the same platform.This can be thought of as a channel or line that is used by devices in the computer to access the memory (RAM) without having to utilize the CPU. It works by allowing the I/O controller that has been previously instructed to transfer a block of data (the size depending on the system) to or from the memory to temporarily control the memory itself by returning the memory address of the data, it can control the memory for as many clock cycles as is required for the process. This system can significantly reduce the workload on the CPU.<br />DNS - Domain Name ServerA domain name is a unique name that is used to identify and locate computers on a network (including the internet), it can be used for websites and/or email addresses. For instance this website's domain name is www.helpwithpcs.com. All machines connected to the internet have their own IP Address, domain names are just an easier way to access a certain machine, for instance if you had to remember IP Addresses instead of domain names it would be cumbersome.<br />DOS - Disk Operating SystemThis is a system that software uses to utilize the disk drives in your computer. See also MS-DOS. IBM® first created DOS® for the series 700 computers years ago, then Microsoft® developed their own version called MS-DOS®, over the years DOS has become outdated due to its limited capabilities, although Windows® still shipped with MS-DOS® until the recent XP version.<br />Dot PitchThis is normally used to describe a monitor's performance, it refers to the distance between the holes of the shadow mask in a CRT display, it can also refer to the distance between each pixel on a color screen, it is measured in millimeters. Generally the smaller the measurement the better the display.<br />Download - DownloadingThis is used to describe when a file is transferred from a remote machine to a local machine using a communications link, for instance when you download a file from a website you are transferring the data from the host to your machine (client). The speed of the download will depend on what connection there is between the two machines and the size of the file to be transferred.<br />DPI - Dots Per InchThis is a measurement commonly used to describe the quality of printers and scanners, it refers to how many pixels per square inch that it is able to print/scan. The higher the DPI the smoother the quality of the image will be when either printed or scanned.<br />DRAM - Dynamic Random Access MemoryA type of memory (RAM) widely used in today's PCs. DRAM works differently to SDRAM as it needs to be refreshed to continue holding the data, this means a slight loss of speed as the memory refreshes itself with a pulse of current to each of its cells.<br />Driver - Device DriverThis is a program that is written specifically to control a certain piece of hardware such as a soundcard, modem, graphics card, printer, scanner etc. Each manufacturer supplies drivers for their specific products, these drivers are often updated with time so it is a good idea to keep your drivers current. To find specific drivers for any of your devices it is best to start at the manufacturer's website as they normally have updated drivers in their respective support pages.<br />E<br />ECC - Error Correcting CodeRefers to a type of Memory (RAM) that automatically checks for errors as the data is passed through.<br />EIDE Enhanced Integrated Drive ElectronicsEIDE refers to an interface standard developed by Western Digital, since around the end of 1994 EIDE controllers have been widely used in the PC industry surpassing the earlier IDE standard due to its faster data transfer rates. The interface controls storage devices like hard drives, CD ROM drives, and CD Writers.<br />EmailThis is a system used by computers to send and receive messages over the internet, when you send an email and likewise when someone sends you an email, the message will remain on the server (your email providers computer) until it is read and deleted, in other words you don't have to be connected to the internet to read an email unlike chat. For more information click here to see our beginner's guide.<br />EPROM - Erasable Programmable Read Only MemoryRefers to a type of ROM that can be erased using an ultra violet light and then reprogrammed using a PROM Programmer. These chips have a small transparent area on the top, this is where the UV light is directed to clear the contents, they come in various different packages which make them very versatile. The ROM will retain the data until it is exposed again to an ultra violet light, it is normal practice to cover the small transparent area to avoid any potential data loss.<br />Ethernet - NetworkingRefers to a standard of the LAN system, Ethernet supports up to 10Mbps per second transfer, a newer implementation of the Ethernet specification 100 Base-T supports up to 100Mbps. The latest standard (Gigabit Ethernet) can support up to 1000Mbps (1 Gigabit). Ethernets are common place in offices where file/device sharing is required.<br />F<br />FAT - File Allocation TableFAT (File Allocation Table) refers to a data table that holds information about how and where files are stored on any one partition (for simplicity think of a partition as all the files on your hard drive).For example, a single file on your hard drive may not be stored in one place, the file could be split up and stored in several different (physical) places (this is called fragmentation), the FAT keeps a record of where the different parts of the file are stored.<br />FirewallRefers to a security program which protects your computer from un-authorised access through a network and/or the Internet. These are very important especially if your computer is connected directly to the Internet for long periods of time.<br />Firewall - iLink - IEEE1394A 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. Apple inc, Sony Corp and a few others helped to develop the IEEE 1394 standard. 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.<br />IEEE 1394/Firewire characteristics:<br />IEEE 1394a - Firewire 400- Data Throughput: 400Mbps- Maximum Cable Length: 4.5 MetersIEEE 1394b - Firewire 800- Data Throughput: 800Mbps- Maximum Cable Length: 100 MetersFirewire® - Firewire is the registered trademark of Apple's IEEE 1394 digital connection.iLink® - iLink is the registered trademark of Sony's IEEE 1394 digital connection.<br />FolderFolder and directory are exactly the same thing, windows refers to them as folders but you will often come across them being called directories. Directories/folders allow information to be stored in your computer in a more convenient way making it easier to organize your files. Directories/folders can be created, renamed and deleted much like files, it is good practice to create these directories/folders and keep your files in them as this helps keep your hard drive organized.<br />FreewareThis is software that is free, and as long as you can put up with the occasional advert there are some programs/utilities out there that are very useful.<br />FTP - File Transfer ProtocolOne of the TCP/IP protocols used for transferring files across TCP/IP connections. The protocol manages the physical transfer of the file along with the representation of the file on both machines involved in the transfer. To upload or download files via FTP you need an FTP program such as Cute FTP.<br />G<br />GHzGigahertz 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.<br />GIF - Graphics Interchange FormatThe 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.<br />Gigabyte - GBThis 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, ie230.<br />Graphics CardA Graphics Card also known as a Video Card is an internal device which controls and produces the display on your screen.<br />GUI - Graphical User InterfaceThis 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.<br />H<br />Hard Disk - Hard DriveA Hard Disk (Hard Disk Drive) is your computer's main storage device. It is where you would normally keep your operating system, programs and files.<br />Hardware - ComponentsThis 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.<br />Host - HostingHost 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.<br />HTML - HyperText Mark-up LanguageHTML is a markup language used to create HTML documents. HTML documents allow plain text to be formatted (bold, italic, etc), as well as being able to specify hyperlinks, images and more.<br />HTTP - HTTPS - HyperText Transfer ProtocolHTTP is a communication protocol used on the internet to allow the communication of 2 computers (devices). HTTPS is a secure adaptation of HTTP, which you will find in common use on secure areas when visiting websites.<br />Hub - Network Hub [Concentrator / Repeater Hub]A Network hub is a device which enables more than one computer (host) to interconnect on a network. They are widely used for creating home, office and other networks.<br />I<br />IDE - Integrated Drive Electronics | ATA - Advanced Technology AttachmentIDE (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.<br />Installation - InstallThis 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.<br />Interface - InterfacingRefers 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 communications) allows data to be sent sequentially down the same line. A parallel interface works in a similar 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.<br />Internet - TCP/IPRefers to a worldwide network of computer systems all using the TCP/IP network protocols. Commonly refers to the world wide web.<br />IP Address - Internet ProtocolThis 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 192.168.1.0.<br />IRQ - Interrupt ReQuestThis 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.<br />ISDN - Integrated Services Digital NetworkThis 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.<br />ISP - Internet Service ProviderISP refers to a company which provides Internet services such as AOL, typical ISPs provide:- A Dial-up server with which to connect to the internet along with a number, username and password.- An Email address.- A POP Server through which to receive emails.- An SMTP Server through which to send emails.<br />Most ISPs also provide web-mail (online email access) which allows you to access your emails from any computer.<br />J<br />JavaJava 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 byte code and can then be run by Java interpreters and runtime environments (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 environment, for example a chat applet can be downloaded and executed within the run time environment integrated into your web browser (Netscape Navigator, Internet explorer, etc).<br />JavaScript - Scripting LanguageJavaScript 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.<br />JPEG - Joint Photographics Experts GroupThis 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 colors 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.<br />K<br />Kbps = kilobits per secondA 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.<br />KernelKernel 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.<br />Keyboard Shortcuts - HotkeysKeyboard 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.<br />Kilobyte - KBA measurement used in digital systems to describe storage capacity, 1 Kilobyte is equal to 1024 (210) Bytes in digital systems.<br />L<br />LAN - Local Area NetworkThese 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.<br />LCD - Liquid Crystal DisplayLCD 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.<br />LPT - Line Printing TerminalThe 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).<br />M<br />Megabyte - MBThis is a measurement used in digital systems such as PCs to describe storage capacity (usually RAM, Hard Drive capacity is mostly stated in Gigabytes these days). Mathematically one Megabyte is 220 (1,048,576) One megabyte is equal to 1024 Kilobytes, so a memory module with a capacity of 256MB can store 268,435,456 Bytes.<br />MHz - MegahertzA frequency measurement, refers to millions of cycles per second, for example a processor running at 500 MHz can handle 500 Million cycles per second. See also GHz, 1 MHz is equal to 1,000,000 Hz. Hertz is named after Physicist Heinrich Hertz.<br />MIDI - Musical Instrument Digital InterfaceRefers to a widely used interface that allows musical instruments such as electric keyboards to be controlled and interacted with by a computer. Most modern soundcards come with some sort of MIDI interface built-in.<br />MIME - Multipurpose Internet Mail ExtensionsA system used for the ASCII (American Standard for information interchange) encoding of binary data for transfer via email on the internet. MIME codes are also used to let the browser know what type of file to expect when it has requested it. For instance, if a browser requests a GIF file, then the host will send in the CONTENT TYPE HEADER the MIME string to indicate that the file is indeed a GIF file and should be processed accordingly.<br />MODEM - MOdulator DEModulatorA communications device used to connect to a network such as the internet. Modems come in various different forms, the most common is the internal modem which uses a PCI interface to connect to the motherboard. Some motherboards come with modems built-in.<br />MotherboardA motherboard (mainboard) is the main circuit board within a PC, most modern motherboards come with the following features:- A processor slot (type will depend on the board specifications)- Memory banks- AGP slot- PCI slots- IDE interface- USB portsThese are just some of the features that a motherboard may have as standard, some motherboards come with integrated components such as a sound card, graphics, modem, NIC (Network Interface Card) and more.<br />All the components inside your PC connect to the motherboard in one way or another, a few examples:- Memory banks are used for RAM modules.- PCI slots are used to provide connectivity for PCI cards such as modems and sound cards.- AGP slots are used for graphics accelerators.- IDE interfaces are used to connect and control IDE devices such as hard drives and CD-ROM drives.<br />Mouse - Pointing DeviceA mouse is a pointing device used to interact with a PC, there are a few different types of mouse available:- Serial Mouse - This is a mouse with a serial connector, it requires a free serial port on your PC.- USB Mouse - This type of mouse has a USB connector and requires a free USB port.- Cordless Mouse - A cordless mouse (as the name suggests) has no cable, this type of mouse utilizes batteries for its power supply.- Optical Mouse - An optical mouse utilizes optical electronics to track the mouse's position and movement, they are preferred over standard mechanical mice as they tend to be more reliable and require less maintenance.<br />MP3 - MPeg-1 audio layer 3Refers to an audio file which has been compressed using the MPEG (see below) compression standard. Using this standard greatly reduces the physical size of the audio file with little or no loss of sound quality.<br />MPEG - Motion Picture Experts GroupA compression standard used for compressing Video and Audio files to a smaller physical size, the compression is achieved by not recording every frame but only the changes between the frames. Motion Picture Experts Group is the name given to the group of people responsible for inventing the standard.<br />MPEG files have either the .mpeg or .mpg file extension and are a very common format due to the high compression.<br />The main implementations of MPEG are:- MPEG-1 - video resolution of 352x240px at 30 frames per second- MPEG-2 - video resolution of up to 1280x720 at 60 frames per secondthese are the most common and the ones you are likely to come across.<br />MS-DOS MicroSoft® Disk operating SystemThis is the system that Windows® based machines use to access and maintain storage devices.<br />N<br />Network - NetworkingA system to allow 2 or more computers to connect to each other and share files or peripherals. Typical types of networks are LAN, WAN and on a wider scale the Internet.<br />Network Switch - SwitchA switch (switching hub) is a network device which is used to interconnect computers and/or devices on a network. They are relatively inexpensive and offer better performance than a hub.<br />NIC - Network Interface CardAn NIC (network interface card) is an expansion card that provides connectivity between a PC and a network such as a LAN, NICs are sometimes called Ethernet adapters. Network Interface Cards (NICs) can be internal or external add-ons and come with various specifications, one of which is transfer rate although most modern network interface cards support up to 100Mbps, and the more expensive Gigabit Ethernet cards supporting up to 1000Mbps.<br />O<br />OEM Hardwareis the term given to a manufacturer that buys hardware from another source, and implements it into their own design. See below for more information. OEM Software means that the software is sold only with a certain piece of hardware and/or the software manufacturer provides no technical support. See below for more information.<br />Online - OfflineOnline - A term given to a person/computer that is connected to a network. Offline - A term given to a person/computer that is not connected to a network.<br />Operating System - OSRefers to the main software of a computer system for instance Windows®, all installed programs run under the control of the operating system.<br />P<br />Parallel Port - ECP - EPP - Parallel InterfaceParallel port/interface refers to a standard 25 pin (D25) connector found on most (if not all) PCs, commonly used for connecting a printer. A standard parallel port transmits 8 data bits at a time, as opposed to a serial port which transmits data one bit at a time.<br />PCMCIA - Personal Computer Memory Card International AssociationA body including hardware and chip manufacturers, system integrators and software houses set up in 1989. A PCMCIA card is a credit card sized device that is used to upgrade memory or add communication devices to notebooks and laptop computers.<br />PDA - Personal Digital AssistantA (Personal Digital Assistant) refers to a hand-held device that incorporates several handy features. PDAs often include an address book, calendar, contacts list, and a memo feature.<br />PDF (Portable Document Format)PDF refers to a type of document (PDF Document) format, which is widely used on the internet. You need software (freely available) called Adobe Reader, in order to view PDF documents.<br />PIXEL - Picture ElementRefers to individual 'bits' of data that form an image, also refers to screen resolution, for example 800x600 is 800 pixels wide and 600 pixels high, 1024x768 is 1024 pixels wide and 768 pixels high.<br />PnP - Plug and PlayPlug and Play was developed by Intel® and Microsoft® and was designed to simplify the installation of new hardware. Windows 95 was the first operating system to include Plug and Play technology. Plug and Play compatible devices communicate with the operating system allowing automated configuration, when a Plug and Play device is connected and the machine re-booted (if not USB) the operating system will acknowledge the new hardware and prompt you for the installation disk that came with the hardware. The device drivers should then be automatically installed.<br />POP - Post Office ProtocolA POP (Post Office Protocol) server allows you to receive your mail through an email client program such as Outlook or Netscape Messenger, this allows you to just connect to retrieve your mail from your email provider, and then you can read your mail offline and can reduce your online time.<br />Port - PortsA communications port on a computer for example the serial port, parallel port, USB port or a port on a server. Different ports have different characteristics and data transfer capabilities, see also Interface.<br />Protocol - ProtocolsA standard set of software instructions which allow a computer to communicate with another and/or other devices.<br />PSU - Power Supply UnitThis regulates and distributes the power to the components inside your PC. The standard now is ATX which can be accessed by the motherboard/software to enable the PSU to be \" put to sleep\" , conserve energy or shut down.<br />Q<br />R<br />RAID - Redundant Array of Independent DisksRAID refers to a hard disk technology which can be used to speed up data transfer and/or provide disk redundancy through disk system fault tolerance. RAID provides these features by utilizing more than one hard disk at a time, there are several variations of a RAID configuration referred to as levels. Each of these levels provide different performance and/or fault tolerance benefits. RAID configurations are commonly found in data critical applications.<br />RAM - Random Access MemoryThis is the main memory in your computer, this is where the computer stores the data it needs when you are using a program. RAM gets its name from the ability to allow the system to access any data stored in the memory in any location at any time. This memory is often referred to as Volatile (power dependent). i.e. when the power is isolated the data is lost. RAM comes in many different packages and there are many different types of RAM all designed to be compatible with a certain system.<br />Resolution - High ResolutionWhen referring to a monitor this measurement depicts the amount of horizontal and vertical pixels i.e. 1024x768, when referring to a printer/scanner it depicts the DPI.<br />ROM - Read Only MemoryROM refers to a type of memory storage which is non-volatile (not power dependant). It cannot be changed using normal methods i.e. written to like RAM. ROMS are widely used for any application that requires data to be stored permanently and/or without a constant supply of power. The BIOS in a digital system is typically ROM based.<br />Router – Network RouterA router is placed at a junction between two or more networks/segments, each network/segment can be using a different topology or protocol. The router will intercept and forward any data packets passing through, most routers can be set up to block certain types of data packets which can be useful for security reasons. The destination address of the data packet needs to be included within the header information, routers don't propagate broadcasts/multicasts. The router will then decide the best route for transferring the data packet to its destination by interrogating a routing table which is either static or dynamically generated.<br />S<br />SATARefers to an interface type used for data storage devices. The SATA interconnect is a serial implementation of the parallel Ultra ATA interface used to connect storage devices such as hard drives & optical drives to a PC's motherboard (host system). The SATA technology starts at a data transfer rate of 150MB/sec, with plans already in place to take it up to 600MB/sec. Some of the advantages of SATA over Ultra ATA:- Cables are easier to work with.- CRC error checking on all data (and control information).- Hot-swap capability.- Less crosstalk due to cable design.<br />SCSI - Small Computer System InterfaceA standard for connecting multiple devices such as hard drives, cd roms, floppy drives, etc, it enables the connection of more devices than its counterpart IDE and normally faster, but the drives tend to carry a bigger price tag.<br />SCSI was originally developed by Shugart Associates and was originally called SASI (Shugart Associates System Interface) before it became standardized.<br />SDRAM - Synchronous Dynamic Random Access MemoryRefers to a type of memory (DRAM) that can synchronize itself with the processor's bus speed, and can run at much higher speeds than it's EDO counterpart.<br />Sector, Track and ClusterA Sector in the context of computing refers to a small area of a storage device, for example a hard disk drive.<br />Serial Port - PortsCommunications port which connects the computer to various peripherals including modems. A serial port transmits data sequentially (one bit at a time) as opposed to parallel ports which transmit 8 bits at a time.<br />Server – Server SoftwareA server is a computer running software that allows it to control the sharing of resources between many computers. Servers are often dedicated to one task depending on what type of server software they are running, below is a summation of a few common server applications: HTTP Server - An HTTP (HyperText Transfer Protocol) server (web server) is typically connected to the internet with a high speed connection and will respond to requests from computers running client software (like a browser) requiring specific data (commonly a web page). This type of server is common to the internet. FTP Server - An FTP (File Transfer Protocol) server is used to transfer files over a network (WAN, LAN or the internet) using the FTP protocol. Mail Server - A mail server stores and transfers (e)mail over a network (WAN, LAN or the internet). Chat Server - A chat server allows its users to transfer real time text between two or more computers, for more on chat click here. Database Server - A database server allows its users to access its database via a network (WAN, LAN or the internet) and depending on permissions, read, delete or alter the contents of its database. This type of server is common place in an office environment. Proxy Server - A proxy server (as the name suggests) typically sits between the client and the main server, it is used to filter data and enable connections to be shared. For example if you are in the UK and you connect to a website that is hosted in the US then the data you send/receive will pass through one or more proxy servers.<br />Shareware - softwareA type of software that is not commercial and normally requires a registration payment to the author, there is normally a trial period.<br />SMTP - Simple Mail Transfer ProtocolAn SMTP server allows you to send emails which have been written within your email client program such as Outlook or Netscape Messenger, this allows you to write your emails offline and then connect for a few seconds to send them. Most email providers supply an SMTP server through which you can send your emails.<br />Software - ProgramsA term given to the programs that a computer executes. A typical example of software would be a word processor or an accounts package.<br />Soundcard - Sound CardThis is an internal device which controls and produces any sounds including music that your PC makes. Sound cards come with various specifications, for example some have more inputs/outputs than others allowing for 5.1 surround sound etc, others have a higher sampling frequency to give better sound recording. Sound cards can also come built-in to motherboards (mainboards), although the built-in cards are usually sufficient for most uses they can be lacking in quality and features if you intend to record or create digital music or sounds.<br />SPAM - SPAM EmailSPAM refers to unsolicited commercial email. The SPAM problem is one that nearly every email user will experience, there are however, ways to decrease the amount of SPAM you receive.<br />SSL - Secure Sockets LayerA protocol developed by Netscape to transfer information via the Internet securely. Web sites use this encryption to allow users to enter credit card numbers and other confidential information, normally you will see the padlock in your browser lock and the URL will begin HTTPS as opposed to HTTP.<br />SVGA - Super Video Graphics ArrayA standard for monitors and graphic cards developed by VESA (Video Electronics Standards Association) which supports resolutions of up to 800x600 Pixels and up to 16 Million Colors.<br />T<br />Terabyte - TBThis is commonly used to describe the capacity of a digital system. A Terabyte is 1,099,511,627,776 bytes (2 to the 40th power).<br />TCP/IP - Transmission Control Protocol / Internet ProtocolA collection of protocols (rules) that depict how data is transferred across networks between computer systems.<br />TIFF - Tagged Image File FormatTIFF (Tagged Image File Format) refers to a type of image format developed by Aldus and Microsoft that is commonly used within computing. TIFF files are basically Bitmap images, they are not restricted in resolution and can be black and white, grey scale or full color.<br />TFT - Thin Film TransistorA type of LCD (Liquid Crystal Display) used in the screen of laptops/notebooks, with 1 to 4 transistors defining one pixel on-screen.<br />U<br />V<br />V90 - V.90A standard used by all modern 56k modems.<br />Virus - VirusesA program that runs on your computer without your knowledge and can cause damage to your files. It usually attaches itself to other programs, a common way to receive a virus is through an attachment via email. Virus protection is extremely important and can save a lot of problems in the future.<br />VPN - Virtual Private NetworkA VPN (Virtual Private Network) refers to a secure network connection that uses the internet to transmit data. The data is typically encrypted using different tunneling protocols such as L2TP(Layer 2 Tunneling Protocol) and PPTP (Point to Point Tunneling Protocol) in which the encrypted data is encapsulated in Internet wrappers before it is transmitted. When the data is received at its destination the Internet wrapper is stripped off and the data decrypted. Typical uses of VPNs would be to create a private WAN without the need to lease dedicated lines or provide travelling employees with a secure connection to company data.<br />W<br />Wait StateThis refers to when a processor or other component has to rest in between clock cycles due to a slower component such as memory. See also zero wait state.<br />WAN - Wide Area NetworkAs the name suggests it is a network of computers over a wide geographical area.<br />WAP - Wireless Application ProtocolWAP (wireless application protocol) refers to a wireless transfer protocol developed by Ericsson, Motorola, Nokia and Unwired Planet. The WAP protocol allows users of handheld devices such as mobile phones to access data and view locally. Some of the wireless networks supported by WAP are listed below:- DataTAC- DECT- CDMA- CDPD- FLEX- GSM- iDEN- Mobitex- PDC- PHS- ReFLEX- TDMAMost WAP devices can support HTML, XML, WML and WMLScript All operating systems can support the WAP specification, although there are operating systems that have been designed with WAP in mind, such as for PDA's (Windows CE and PalmOS are 2 examples).<br />WAV - WAV audio fileAn audio file format developed jointly by IBM and Microsoft, WAV audio files have a file extension of .wav and are commonly used within the Windows environment.<br />WIFIWI-FI refers to a type of wireless technology which allows users to connect to a local network without the need for cables, also known as a WLAN (Wireless Local Area Network).<br />WLANrefers 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.<br />WWW - World Wide WebDescribes the internet as a whole, millions of computers all over the world connected via phone lines and modems.<br />X<br />Y<br />Z<br />Zero Wait StateRefers to a system that allows the processor to work at full clock speed regardless of the clock speed of the memory (RAM).<br />ZIF - Zero Insertion ForceRefers to a type of chip (processor) socket with which an arm or release device is used to lock the chip in place.<br />Below we have compiled a useful directory of Mac Keyboard Shortcuts. <br />Startup<br />KeystrokeDescriptionPress X during startupForce Mac OS X startupPress Option-Command-Shift-Delete during startupBypass primary startup volume and seek a different startup volume (such as a CD or external disk)Press C during startupStart up from a CD that has a system folderPress N during startupAttempt to start up from a compatible network server (NetBoot)Press T during startupStart up in FireWire Target Disk modePress Shift during startupStart up in Safe Boot mode and temporarily disable login items and non-essential kernel extension files (Mac OS X 10.2 and later)Press Command-V during startupStart up in Verbose modePress Command-S during startupStart up in Single-User mode<br />Finder Window<br />KeystrokeDescriptionCommand-WClose WindowOption-Command-WClose All WindowsCommand-Right ArrowExpand Folder (list view)Option-Command-Right ArrowExpand Folder and Nested Subfolders (list view)Command-Left ArrowCollapse Folder (list view)Option-Command-Up ArrowOpen parent folder and close current window(Assigned in Keyboard & Mouse Preferences)Show Package Contents (of selected file in Mac OS X 10.5 or later only). To create this contextual menu shortcut, open Keyboard & Mouse preferences in Mac OS X 10.5, click Keyboard Shortcuts, click the \" +\" button, choose Finder.app as the Application, and type \" Show Package Contents\" (exactly), and set whichever shortcut you want, such as Command-Control-S.<br />Menu Commands<br />KeystrokeDescriptionShift-Command-QApple Menu > Log outShift-Option-Command-QApple Menu > Log out immediatelyShift-Command-DeleteFinder Menu > Empty TrashOption-Shift-Command-DeleteFinder Menu > Empty Trash without dialogCommand-HFinder Menu > Hide FinderOption-Command-HFinder Menu > Hide OthersCommand-NFile Menu > New Finder WindowShift-Command-NFile Menu > New FolderCommand-OFile Menu > OpenCommand-SFile Menu > SaveShift-Command-SFile Menu > Save AsCommand-PFile Menu > PrintCommand-WFile Menu > Close WindowOption-Command-WFile Menu > Close ALl WindowsCommand-IFile Menu > Get InfoOption-Command-IFile Menu > Show Attributes InspectorCommand-DFile Menu > DuplicateCommand-LFile Menu > Make AliasCommand-RFile Menu > Show OriginalCommand-TFile Menu > Add to Favourites (Mac OS X 10.2.8 or earlier), Add to Sidebar (Mac OS X 10.3 or later - use Shift-Command-T for Add to Favourites)Command-DeleteFile Menu > Move to TrashCommand-EFile Menu > EjectCommand-FFile Menu > FindCommand-ZEdit Menu > UndoCommand-XEdit Menu > CutCommand-CEdit Menu > CopyCommand-VEdit Menu > PasteCommand-AEdit Menu > Select AllCommand-1View Menu > View as IconsCommand-2View Menu > View as ListCommand-3View Menu > View as ColumnsCommand-BView Menu > Hide ToolbarCommand-JView Menu > Show View OptionsCommand-[Go Menu > BackCommand-]Go Menu > ForwardShift-Command-CGo Menu > ComputerShift-Command-HGo Menu > HomeShift-Command-IGo Menu > iDiskShift-Command-AGo Menu > ApplicationsShift-Command-FGo Menu > FavoritesShift-Command-GGo Menu > Go to FolderCommand-KGo Menu > Connect to ServerCommand-MWindow Menu > Minimize WindowOption-Command-MWindow Menu > Minimize All WindowsCommand-?Help Menu > Open Mac HelpCommand-SpaceOpen Spotlight (Mac OS X 10.4 or later)Command-escFront Row - Activates Front Row for certain Apple computers<br />Universal Access and VoiceOver<br />KeystrokeDescriptionOption-Command-8Turn on ZoomOption-Command-+(plus)Zoom InOption-Command--(minus)Zoom OutControl-Option-Command-8Switch to White on BlackControl-F1Trun on Full Keyboard Access. When Full Keyboard Access is turned on you can use the key combinations listed below from the Finder.Control-F2Full Keyboard Access > Highlight MenuControl-F3Full Keyboard Access > Highlight DockControl-F4Full Keyboard Access > Highlight Window (active) or next window behind itControl-F5Full Keyboard Access > Highlight ToolbarControl-F6Full Keyboard Access > Highlight Utility window (paletteControl-F5 or fn-Command-F5Turn VoiceOver on or off (Mac OS X 10.4 or later)Control-Option-F8 or fn-Control-Option-F8Open VoiceOver Utility (Mac OS X 10.4 or later)Control-Option-F7 or fn-Control-Option-F7Display VoiceOver menu (Mac OS X 10.4 or later)Control-Option-; or fn-Control-Option-;Enable / Disable VoiceOver (Mac OS X 10.4 or later)<br />The Universal Access preference pane allows you to turn on Mouse Keys. When Mouse Keys is on, you can use the numeric keypad to move the mouse. If your computer doesn't have a numeric keypad, use the fn (function) key.<br />Mouse Keys<br />KeystrokeDescription8Move Up2Move Down4Move Left6Move Right1, 3, 7, and 9Move Diagonally5Press Mouse Button0Hold Mouse Button. (period on keypad)Release Mouse Button (use after pressing 0)<br />Other Commands<br />KeystrokeDescriptionOption-Command-DShow/Hide DockCommand-TabSwitch ApplicationTabHighlight next itemCommand-Up ArowMove up one directoryCommand-Down ArrowMove down one directoryPage Up or Control-Up ArrowMove up one pagePage Down or Control-Down ArrowMove down one pageOption-DragCopy to new locationOption-Command-DragMake alias in new locationCommand-DragMove to new location without copyingShift-Command-CShow Colors Palette in applicationCommand-TShow Font Palette in applicationCommand-Shift-3Take a picture of the screenCommand-Shift-4Take a picture of the selectionCommand-Shift-4, then press Control while selectingTake a picture of the screen, place in ClipboardCommand-Shift-4, then SpacebarTake a picture of the selected windowOption-Command-escForce QuitControl-EjectRestart, Sleep, Shutdown dialog boxControl-Command-EjectQuit all applications and restartOption-Command-Eject or Option-Command-PowerSleepCommand-click window toolbar button (upper right corner)Cycle through available views for the window's toolbar (dependent on the nature of the Finder or applciation window)Command-`Cycle through windows in application of Finer (if more than one window is open)Function-Delete (portables only e.g. PowerBook, iBook, MacBook, MacBook Pro)Forward Delete (delete the character to the right of your cursor<br />Below we have compiled a useful directory of PC Keyboard Shortcuts. <br />CTRL Commands<br />Keyboard ShortcutResult in Windows® XP - GeneralCTRL+ASelects all the items in the active windowCTRL+CCopies the item or items to the Clipboard and can be pasted using CTRL and VCTRL+FDisplays the Find all files dialog boxCTRL+GDisplays the Go to folder dialog boxCTRL+NDisplays the New dialog boxCTRL+ODisplays the Print dialog boxCTRL+PDisplays the Print dialog boxCTRL+SDisplays the Save dialog boxCTRL+VPastes the copied item or items from the ClipboardCTRL+XCuts the item or items selected to the ClipboardCTRL+ZUndoes the last actionCTRL+F4Closes the active document windowCTRL while dragging an itemCopy the selected itemCTRL+SHIFT with arrow keysHighlight a block of textCTRL+ESCDisplay the Start menuCTRL+F6Opens the next document window in the active application<br />ALT Commands<br />Keyboard ShortcutResult in Windows® XP - GeneralALT+ENTERView the properties for the selected itemALT+F4Close All WindowsALT+SPACEBAROpen the shortcut menu for the active windowALT+TABSwitch between the open itemsALT+ESCCycle through items in the order that they had been opened<br />F-Key Commands<br />Keyboard ShortcutResult in WIndows® XP - GeneralF1 keyGive help on the active window or selected itemF2 keyRename the selected itemF3 keySearch for a file or a folderF4 keyDisplay the Address bar list in My Computer or Windows ExplorerF5 keyUpdate the active windowF6 keyCycle through the screen elements in a window or on the desktopF10 keyActivate the menu bar in the active program<br />Windows Key Commands<br />Keyboard ShortcutResult in WIndows® XP - GeneralWindows LogoDisplay or hide the Start menuWindows Logo+BREAKDisplay the System Properties dialog boxWindows Logo+DDisplay the desktopWindows Logo+MMinimize all of the windowsWindows Logo+SHIFT+MRestore the minimized windowsWindows Logo+EOpen My ComputerWindows Logo+FSearch for a file or a folderCTRL+Windows Logo+FSearch for computersWindows Logo+F1Display Windows HelpWindows Logo+LLock the keyboardWindows Logo+ROpen the Run dialog boxWindows Logo+UOpen Utility Manager<br />General Keyboard Shortcuts - Dialogue Box<br />Keyboard ShortcutResult in WIndows® XP - Dialogue BoxTABMove forward through the optionsSHIFT+TABMove backward through the optionsCTRL+TABMove forward through the tabsCTRL+SHIFT+TABMove backward through the tabsALT+Underlined LetterPerform the corresponding command or select the corresponding optionENTERPerform the command for the active option or buttonSPACEBARSelect or clear the check box if the active option is a check boxF1 keyDisplay helpF4 keyDisplay the itmes in the active listArrow KeysSelect a button if the active option is a group of option buttonsBACKSPACEOpen a folder one level up if a folder is selected in the Save As or Open dialog box<br />Windows Explorer Shortcuts<br />Keyboard ShortcutResult in WIndows® XP - Windows ExplorerENDDisplay the bottom of the active windowHOMEDisplay the top of the active windowNUM LOCK+Asterisk Sign (*)Display all of the subfolders that are under the selected folderNUM LOCK+Plus Sign (+)Display the contents of the selected folderNUM LOCK+Minus Sign (-)Collapse the selected folderLEFT ARROWCollapse the current selection if it is expanded, or select the parent folderRIGHT ARROWDisplay the current selection if it is collapsed, or select the first subfolder<br />