Asynchronous Digital Subscriber Lines provide a form of broadband Internet access.
Telephone companies provide subscribers with Micro Filter Adapters, which plug into an existing telephone line. The adaptor has two sockets – one for a phone (Phone Jack Connector) and another for a modem (RJ-11), this splits data and voice signals on the line for simultaneous Internet and phone use.
To connect a computer, an RJ -11 telephone/modem cable goes from the adaptor to a modem, which is specifically designed for ADSL access. There are three types of these modems:
Ethernet ADSL Modem: Connects to a computer through its Ethernet port with a RJ-45 cable.
USB ADSL Modem: Connection through the computer’s USB port, using a USB cable.
PCI ADSL Modems: An internal modem fixes into the computer’s PCI slot, allowing a cable to connect directly to the filter adaptor.
Another option is an ADSL router, which acts as a hub, enabling multiple users in a household to go online by connecting to it, rather than plugging into different telephone sockets. These routers have internal modems, so a separate modem is not required.
Anti-virus software packages provide protection by scanning a computer’s files, email attachments and internet downloads, seeking out and killing malicious computer programmes. If the software detects anything harmful, it will warn the user and give them the option of eliminating the threat. Packages are designed to perform regular scans, and are updated to protect against new viruses.
Cutting edge technology and stylish designs sum up the Apple brand. Unlike the majority of PCs on the market today, which operate using Microsoft Windows, The Apple Corporation manufactures personal computers (Apple Macintosh – iMacs etc), which use their own operating systems. The company also produces the highly successful personal music player, the iPod.
AVI (Audio Video Interleave)
This is one of the most common types of media file that a computer user will come across when they download and play clips from the internet. Created by Microsoft in 1992, these files combine audio and video in a compressed format and can be played on the standard Windows Media Player.
Bandwidth can be looked at in two ways:
Firstly, a high speed internet connection via an ADSL or cable line has more bandwidth, which means that information (data) can be transferred at a faster rate – ie you can download files and view websites much quicker. As well as this, an internet connection with more bandwidth has the capacity to deal with higher levels of traffic, meaning more people can be online at the same time.
Secondly, in order to prevent excessive usage, some Internet Service Providers also impose a bandwidth or download limit on its users, which basically means that users are only allowed to upload (send) or download (receive) a certain amount of data. Therefore, a frequent user who goes online to download music will use up their allotted bandwidth before someone who just views websites -the average audio file size is 4Mb compared to 50Kb for a webpage.
BIOS stands for Basic Input/output system and basically helps set up a computer every time it starts/boots up. When the computer is switched on, the BIOS program runs a process of checks, viewable on screen, and will go through how much memory the system has, the speed of the processor. It will then run checks on the computer’s hardware – Hard Disk, CD Drive, and peripherals (keyboard, mouse) to confirm what type they are and that they are attached and working, before loading the operating system.
The other function of the BIOS is to acknowledge the presence of updated hardware such as RAM or when a new piece of equipment is added to the computer.
Bluetooth is a form of wireless technology. Most people will be familiar with hands free mobile phone headsets. Bluetooth also enables PCs and laptops to connect over short-range radio frequencies to other devices such as printers, keyboards, mobile phones and digital cameras. For a computer/laptop to connect to other devices it must be enabled via a USB Bluetooth adaptor or a Bluetooth card.
When you think of broadband, you think of high-speed internet access. Connecting to the internet in this way is becoming more popular than the traditional “dial up modem” method, as it is significantly faster and also because you are always connected.
This technology is available to consumers in two ways: ADSL or Cable.
Broadband packages come in the following speeds: 512Kb, 1Mb and 2Mb. When it comes to downloading a song file or viewing web pages, a 512Kb broadband connection is ten times faster than the standard dial up connection, which is 56Kb.
The amount of data that can be stored on a computer is measured in bytes. Users will come across this unit of measurement, when they see specifications for hard disk space and memory size (RAM).
1024 bytes = 1 Kilobyte (Kb)
1024 Kilobytes = 1 Megabyte (Mb)
1024 Megabytes = 1 Gigabytes (Gb)
High speed Internet access supplied by cable TV companies, using coaxial TV wires, instead of telephone lines. When cable broadband companies first appeared, they provided subscribers with an Ethernet network card, which plugged into the computer’s PCI slot, from which an RJ-45 Ethernet cable would then connect to a set-top box.
Now companies such as Virgin Media give customers a cable modem (not to be confused with ADSL modems) and a signal splitter to connect to their broadband service. A line from the main coaxial cable point runs to the signal splitter, from here two further coaxial wires feed into the set-top box (for digital TV) and the cable modem (Internet). An RJ-45 network wire connected to the modem then plugs into the into the computer’s Ethernet card/port.
Multiple users can also connect to the Internet at the same time via a cable broadband router. However unlike ADSL routers, cable routers do not have built-in modems, so they have to be connected to a modem that is designed for use with cable broadband.
Cache refers to a computer’s short term memory banks, where frequently used data and information, in the form of web pages for example, can be accessed quickly without having to download them repeatedly. This means the computer is able to perform quicker and more efficiently.
Caches are built into the computer’s processor (L1 cache) and are also located on the motherboard close to the processor (L2 Cache).
(compact disc read only memory) CDs have become the standard way of storing data, from software programs to audio and video. They have replaced floppy discs due to their huge capacity to hold information. Since the introduction of the original read only discs, which are used mainly for the distribution of software, CDs have progressed technologically and this has seen the development of new formats in recent times, including the CD-R (compact disc-recordable) and CD-RW (compact disc-rewriteable).
CD-R disks are very popular for the reason that they allow people to download music from the Internet and create their own personalised CD collections, however they can only be recorded onto once. CD-RW discs on the other hand are reusable and can be over written more than once and so come in handy for people who need to back up their work on a regular basis.
While there was a time when CDs were only compatible with CD drives/burners, they can now be played and recorded on DVD combo drives.
The majority of music and video files downloaded from the internet come in a compressed format, because otherwise they would take up too much space. In order to play these files, media players require codecs, which are basically decoders used to unpack and initialise the playback of the audio and video data.
There are many types of codec available and each one is specifically designed to play the different formats of media files that exist today. Most of them will come as part of the Windows operating package, however there might be times when a media player cannot play a particular file, in which case it will inform the user, and then either try to automatically download the appropriate codec or direct you to where you can get it on the internet.
When a user visits a website, the site will create a data file on the PC, which remembers your preferences, in terms of how you use the site, as well as storing login information for websites that you visit on a regular basis, such as email accounts. Cookies also come into use when you shop online, so if you are purchasing multiple items, a file is made by the website to memorise what is in your shopping cart.
While there are positive aspects to cookies, they also have some negative associations, with regards to privacy issues. It is argued that companies can keep track of computer users, in terms of how they surf the web, and also by keeping a tab on the kinds of online transactions that are made. This can allow websites to target people with their advertising.
(digital video interface) Traditionally computers have hooked up to monitors via a VGA cable connector, however DVI connectors are fast becoming the new standard because of the quality of the signal delivery, which produces a better picture. Most manufacturers of flat panel LCD monitors and videographic cards are now either replacing VGA with DVI ports or have both featured on their products.
(digital versatile disk) DVD’s are very popular within the computer industry because they can store far greater amounts of data on them compared to a CD.
As with read only CDs, read only DVDs, which are originals released through film distributors – the kind users will either rent or buy, cannot be recorded on, but can be played on any DVD drive.
DVDs come in a variety of formats and this is where things can get tricky, especially when it comes to recording and copying. There are DVDs that are marked with the “-” symbol. Companies such as Sony, Hewlett-Packard and Dell support this format.
DVD-R are recordable discs – but can only be overwritten once, whereas DVD-RW discs can be recorded on again and again.
The other format available on the market today is marked with the “+” symbol, compatible with systems manufactured by Samsung, Toshiba, Apple etc. DVD+R discs can only be recorded on once compared to DVD+RW, which can be overwritten on numerous occasions.
DVD dual layer disks are also available in both competing formats. These are double sided and have twice the storage capacity.
When computer companies started to produce multi format DVD rewriters, this meant that users no longer had to choose a format, which was compatible with their system, and could use +/- disks on one DVD drive. Computers and laptops are now released with DVD combo drives – these can not only play, record and copy DVDs, but also CDs, making things much more convenient.
Ethernet refers to the process of connecting a number of computers to a local area network (LAN). In a business environment such as an office, this would allow the sharing of files and other hardware devices amongst the workforce.
Ethernet or Network cards, slot into a computer’s PCI slot and allow users to connect to a network such as the Internet via a network cable (RJ -45). For home users who subscribe to cable broadband – the network cable would go from your set-top box or cable modem and fits into the Ethernet/Network card’s port.
With computers being constantly connected to the internet through broadband, this can leave them vulnerable to attacks. This type of software acts as a security barrier, which works in conjunction with anti-virus programs to prevent hackers and spammers from infiltrating your computer and also can be used to control what kind of websites are being accessed.
This high-speed digital data transfer connection was developed by Apple and is a competitor of the USB connection. These connectors can be found on a variety of devices ranging from digital cameras to video camcorders. Sony also created their own version called iLink, however while the IEEE1394 connector standard is particularly good for the transfer of large amounts of data, it does not feature on as many products as the USB connector and is more expensive.
This card is either built in or can be fitted into a computers expansion slot and controls the quality of the display on your monitor. All graphics cards have their own level of memory, measured in bytes. Some inbuilt cards (located on the actual motherboard) borrow memory from the PCs main memory bank (RAM). By using these resources, this affects the computer’s overall performance. Other cards (which slot in via PCI or AGP slots) have their own independent level of memory. These cards process pictures much faster and produce better images and graphics, when it comes to games and other software, such as photo-editing packages.
The speed of a computer processor is measured in GHz, which literally translates into billions of cycles (hertz) per second. Modern computer systems on the market today will have processors ranging from 1 GHz to 3 GHz. Obviously the more GHz, the better your computerwill perform.
1GHz = 1000 MHz (Megahertz)
1 MHz = 1,000,000 Hz
Hard disk (HDD – Hard Disk Drive)
The purpose of a Hard Disk Drive is to store data files (music, video or work documents) and software. Coming in various sizes that can range from 40Gb to over 200Gb, this primary storage device is fitted into a computer and is labeled as Local Disk (C:) in the My Computer folder.
External hard drives connect via a USB connection to a computer or laptop, and are becoming popular with users who want to copy and backup files for safety, as well as for people who require extra capacity. This means that users are no longer restricted, once their computer’s original hard drives have run out of space. They are also very convenient for business users, who are always on the move and require flexibility.
(HyperText Markup Language) This is the basic programming language used to create web pages. When viewed, an HTML page will include a series of commands and symbols, which will dictate how a website will look, by indicating where images will be placed, what colours will be used, where to link one page to another – known as Hyper-linking. This information will then be translated by whichever web browser software is being used to present the website in its completed online format.
(HyperText Transfer Protocol) Users will be familiar with this term, because whenever you visit a website on the internet, the web address (URL) you see at the top of the page will start with ‘http’. The HyperText Transfer Protocol is basically a procedure that instructs a web browser to find the website you are looking for and then load up the page.
The development of the internet has revolutionised the way people communicate around the world. Through Internet Service Providers (ISP), users can connect via phone or cable lines to a global network, where they can send or receive news and information through email, have access to a wide range of useful resources including the ability to shop online. They can also make phone calls, chat online, download music, pictures and videos.
An intranet is a smaller version of the internet and is specifically created by businesses to allow its employees to share and view information about the company they work for. The biggest difference between the two is that, whereas the internet is a global network and gives people unlimited access to websites, an internal company intranet service will provide partial or no access to outside websites.
(Internet Protocol) Every computer that connects to the internet is given an IP Address. This is a set of unique numbers, which are split into four sections (i.e. 18.104.22.168), and are used to identify your PC when you go online. In other words, like a phone number or street address for your home, this number can verify who the user is and the location of their computer.
ISP (Internet Service Provider)
As the name suggests, these are the companies that provide internet services to consumers. There are many different ISPs available today, with companies offering a choice of dial-up and broadband connections. The market has become very competitive, especially with the entry of the cable and satellite giants, who now provide a combination of telephone, internet and TV packages to users. As a result, prices have been driven down and the technology is more widely accessible.
(Joint Photographic Experts Group) Developed by the Joint Photographic Experts Group, this is the most common type of image format used to display photo-quality pictures on websites. Compared to other image formats such as, BMP (Bitmap) and TIF (Tagged Image Format) files, JPEGs can compress pictures by 90%, meaning they will take up less space when downloaded, and will load up much faster. Despite the reduction in size, JPEG files retain the quality of the image.
LAN (Local Area Network)
The best way to describe a Local Area Network is to think of an office environment where a group of computers are connected to enable workers to share the use of printers, photocopiers, etc as well as allowing them to communicate – send and receive data and files through a company’s internal intranet and email service.
Where several Local Area Networks are connected together over a broader area through telephone lines, this is called a Wide Area Network (WAN) – the biggest of which is the internet.
The advent of wireless technology has seen the development of Wireless Local Area Networks (WLAN), which performs the same function, but use radio signals to connect computers and other devices in a network rather than cables.
(Liquid Crystal Display) LCD technology was primarily used for laptop displays, but it has gradually entered the desktop market, eclipsing the bulky CRT (cathode-ray tube) monitors of the past. TFT or (Thin Film Transistor) monitors are a popular type of LCD and distributed with most computer systems.
Characterised by their super sleek designs, the screen is made up of two layers, which sandwiches a solution of liquid crystal. The display powers up, when an electric current passes in between the two layers, producing light, which filters through the liquid crystals.
While LCD monitors are considered to be far superior compared to CRT displays in terms of providing sharp picture quality, they can easily be damaged because of fragility of the thin screen, similar to what can happen to a calculator display, if pressed or dropped.
Laptop (Notebook Computers)
When they first appeared on the market, laptops provided a convenient portable solution for business travellers, who needed important information and data at their fingertips. They are still primarily designed for those on the move but more home users are buying them as desktop replacements. Modern systems have specifications, which match their desktop counterparts, both in terms of power and multimedia accessories.
Memory cards (Expansion Cards)
The first, and still one of most commonly used memory cards on the market today, is the PCMCIA or PC card. These were initially designed to slot into laptops to increase memory, but have since developed to enable other forms of hardware to be added in this way, like modems or ethernet/network and WIFI cards.
There are now many different types of memory card, many of which function as mini portable hard drives, which allow people to store files from devices such as digital cameras and camcorders and then to transfer them to their PCs and laptops. These cards come with a variety of storage sizes and transfer speeds.
Compact Flash Cards and Smart Media Cards were introduced as alternatives to the PC Card, and are mainly used with digital cameras. Manufacturers then created smaller card formats like the Multimedia Card, which are compatible with mobile phones and MP3 players. Portable Data Storage Keys or Memory Sticks are another version and hook up to a computer through a USB connection.
PCs and laptops either have built in slots for memory cards, or people can use Memory Card Readers – a separate external device, which connects via a USB port to a computer system.
This hardware device makes it possible for a computer to connect to the internet through the telephone line. There are many different types of Modem, including an internal format, which plug directly into a computer’s motherboard via a PCI slot. They can also come inform of a separate external device and these can be attached to a PC by using its USB, Serial or Ethernet interface port.
This is the main circuit board inside a computer and basically holds everything together. The processor (CPU – Central Processing Unit) along with the memory bank (RAM) is built into the board. Components like the Hard Drive and the CD/DVD drives connect via ribbon cables to IDE (Integrated Drive Electronics) interfaces, whereas other external hardware devices such as modems, graphics and sound cards will plug into the expansion slots, of which there will be several. USB, Serial and Parallel ports are also integrated on to the motherboard.
(Moving Picture Expert Group) This commonly used media format, named after the people who created it, basically compresses video and audio files into a more manageable size, while at the same time delivering high quality pictures and sound.
Media formats are distinguished by video resolution – measured in pixels per line on a monitor and the rate at which images are displayed (FPS – frames per second). In terms of playback quality, MPEG-1 and MPEG-2 files are far better and more reliable compared to other formats such as AVI.
MPEG-1 – 30 frames per second – video resolution – 352×240
MPEG-2 – 60 frames per second – video resolution – 1280×720
AVI – 15 frames per second – video resolution – 320 x 240
(Note: The more frames per second, the smoother the playback and a higher resolution provides video standard movies)
(MPEG-1 Audio Layer 3) These digital audio files are a derivative of the MPEG format, and are compressed considerably to a size, making them faster to download and easier to transfer from computers to MP3 players. As a result MP3s have become an extremely popular format amongst music fans, as they can save high quality versions of their favourite songs from the internet to their computers, which can then be shared, played or moved to portable players.
From a computer user’s perspective, this is the most important piece of software they will own, as it helps them manage every aspect of their PC. Through this program, people can personalise their computers, from the way their main screens (desktop) will look, as well as determining how the system will respond to their commands.
The operating system is functional in the sense that it co-ordinates basic tasks – by running other software, it will also organise the computer’s resources efficiently, in terms of memory allocation, and make sure that devices such as the mouse, keyboard, hard disk, CD/DVD drives and other internal components such as graphics and sound cards, are set-up correctly.
Currently, Windows XP is the main operating system that is distributed with PCs, however the new Vista version is now on the market.
PC (Personal Computer)
PCs have come a long way since they were first appeared more than two decades ago. Back then IBM and Apple dominated the computer market, but as time went on other companies began to introduce their own cheaper versions of the personal computer. As a result, consumers now have a wide range of choice, where they can select between branded or custom built (unbranded) basic and high-spec models.
(Peripheral Component Interconnect) Developed by the Intel Corporation, these sockets, which are sometimes referred to as expansion slots, are built onto a computer’s motherboard, and allow users to insert graphics, sound and network cards in order to enhance the ability of their computer system. As well as having a number of PCI slots, Desktop computers are now incorporating PCI express slots, which will eventually replace the older sockets. The express slots were designed to improve the performance of computers, especially in terms of providing a better platform for graphics.
Processor (CPU – Central Processing Unit)
At the heart of every PC is its processor and this is the driving force behind every task that a computer will carry out. The most important asset of a processor is its speed, in other words a computer with a 2GHz CPU will perform better than one with a 500MHz processor.
There are now computers that have Dual-Core processors, which effectively means that there are two processors instead of one. This makes multi-tasking – the ability to run a number of different software at the same time much easier and faster.
The leading manufacturers in this field are Intel and AMD, with both companies producing many different types of budget and high-spec processors – though it is generally accepted that AMD make high-end CPU’s more accessible because of their lower costs.
(Random Access Memory) This is the primary memory bank of a computer and is an essential piece of hardware as it works with the CPU to make software run smoothly. The more RAM you have, the more efficient a computer will be. This especially comes into play when a user is running several different programs at the same time, because each application being used will take up a certain amount of memory, as it stores data that is being accessed.
Software applications will state a specific requirement of RAM, measured gigabytes (Gb) or megabytes (Mb), which is needed for it to work properly. Modern computers come with DDR (Double Data Rate) memory, which processes data much faster than previous types of RAM.
RAM can be upgraded by inserting sticks of memory (RAM Modules) into DIMM slots, which are located on the motherboard. For laptops, RAM can also be added via a PCMCIA Card (Personal Computer Memory Card International Association).
A Sound card is an audio input/output device that converts digital and analogue signals to produce high quality surround sound playback for music, DVDs and games.
As a result of this process, people can to listen to music and other sounds from a computer via speakers or headphones. Microphones can also be connected so that users can talk to one another through Internet phone applications and chat rooms. The cards can also be useful for those wanting to record and create music on their computer by attaching other forms of music and audio equipment.
There are many types of sound cards available, with some being built into the computer’s motherboard, but the most sophisticated ones come in the form of an expansion card, which plugs into a PCI slot, or as separate external devices.
(Uniform Resource Locator) When a person refers to a URL, they are basically talking about a web address. A URL for a website consists of:
Http:// – the Hyper-Text Transfer Protocol – which instructs a web browser to find the website you are looking for and then loads up the page.
Domain Name – this is the identity of the site you are visiting – in this case, it would be: bookshelfboyfriend.com
Path name – this is name of the particular section of the website that you are looking for – so if you want to see the terms and conditions of the Bookshelf Boyfriend website, you would go to http://www.bookshelfboyfriend.com/computing-terms/ – where “terms” would be the path name.
(Universal Serial Bus) USB connection ports provide a convenient method of adding devices to computers and laptops. The majority of electrical products on the market today make use of USB connectors, because they offer a faster and more reliable way of transferring data between printers, digital cameras and MP3 players to a computer.
By incorporating USB ports, computer manufacturers have phased out the use of previous standard connectors, such as Parallel and Serial ports. The 25 pin parallel port was mainly used to connect printers to computers, where as the serial port was used to attach a mouse and keyboard. But these methods are cumbersome compared to a USB, which features Plug and Play – this means that you can plug in a device into a USB port and the computer will automatically recognise it and make it work straight away, without you having to restart your computer.
VGA (Video Graphics Array)
VGA is a standard interface used to connect a monitor to a computer. Many monitors have an analogue DB15-pin cable, this plugs into a computer’s Graphics Card, via its VGA port. A graphics card generates a digital image and converts it into an analogue signal, which passes through the cable and displays a picture on the screen. While many graphics cards and monitors still incorporate VGA, manufacturers have also introduced the DVI (Digital Visual Interface), which is designed to send digital signals through a cable to a monitor in order to produce more clearer and better quality screen resolution for users.
Computer viruses are malicious programs, which are designed to infiltrate a computer, causing it to crash and damage and erase stored files. Viruses can infect a computer through files that are attached and sent through emails, or when a user downloads a file from a less than trustworthy website.
Viruses are rated by the amount of damage they can inflict. Anti-Virus software manufacturers usually list threats on their websites with updated bulletins, advising people how to avoid a potential new virus.
Very often people are unaware that their computer has a virus, until it is too late. Some of the worst examples include Spyware and Trojan programs, which by their very nature will sneak into your system, hide and then strike. Depending on how sophisticated they are, these types of programs will leave your system highly vulnerable, because they can allow other people (remote users) to access your computer’s Internet account, passwords and other personal details.
(Waveform Audio Format) This is an uncompressed audio file format, which has become less popular in recent times because of the development of the MP3 file format, which takes up less space in terms of storage and is easier and faster to transfer over the internet through file sharing activities.
Despite this, some people still choose to use WAV files because they retain their original quality in terms of music playback, as well as the fact that they are playable on a wider range of computer audio player applications compared with other formats.
(Wireless Fidelity) Wi-Fi technology enables a computer or laptop to connect to the internet without cables or wires. The process requires a PC or laptop to have an integrated Wi-Fi device or an external wireless network card (PCMCIA card) attached. Then with the help of wireless router, which can either be purchased or be supplied by broadband internet providers, a computer will detect the service provider’s network from anywhere in a home and connect.
As this technology gets rolled out, more and more Wi-Fi Hotspots are becoming accessible, which effectively means that when you are the move, you can surf the internet in shops, hotels and other places that support wireless services.
As well as connecting to the Internet in this way, a computer can also connect to other electronic equipment, such as printers if they are Wi-Fi enabled.
WWW (World Wide Web)
Created by Tim Berners-Lee in 1990, the World Wide Web is revolutionary resource that is made up of a massive collection of web pages, which are created using HTML, and contain text, images and multimedia in the form of audio and video. Using browser software such as Netscape or Internet Explorer, users can go online and access a wealth of information by simply clicking their mouse on hyperlinks to go from one website or webpage to another.
[image: Terence Wass]