Explain the component parts of a computer system - Include both hardware, software and the types of printer available.
ANNIE MACKENZIE
HE ACCESS TO BUSINESS STUDIES & COMPUTING
USING BUSINESS INFORMATION TECHNOLOGY
ASSIGNMENT NO.1A
TASK ONE - Explain the component parts of a computer system. Include both hardware, software and the types of printer available.
A computer is a machine that processes information and is made up of different components. A computer system can be divided into hardware and software.
Hardware
Hardware is the name for all the parts of a computer system that can be touched, for example the mouse or keyboard. Basically these devices can be split into:
* Central Processing Unit (CPU)
* Input devices
* Output devices
* Backing store (Memory)
The central processing unit
The CPU is the brain of the computer. It is responsible for processing the data and turning it into information that we can understand. There are three main elements of the CPU:
* The control unit which co-ordinates the input and output devices.
* The arithmetic and logic unit, which performs all the calculations and makes all of the logic decisions.
* The immediate access store, which provides immediate memory for holding data and programs.
Input devices
An input device receives data and sends it to the central processing unit. The input device converts the data into binary form that the computer processor can understand and accept.
Keyboard - This is probably the most widely used and simplest of input devices. On the typical keyboard the layout of the keys is based on the 'QWERTY' layout the same as on a standard typewriter but with extra keys that are required to enable control signs to be sent to the computer.
Mouse - This is a mouse shaped object designed to fit under a hand while it is moved about over a desk. It has a metal or rubber ball protruding from its base that together with the internal mechanism detects movements and converts them to electronic signals. The mouse is also provided with buttons to press. These are pressed to produce an action when the user has moved the cursor to the right place.
Microphone - Using a microphone human speech is coded into a sequence of electrical signals. The computer then searches a vocabulary of stored sound signals for the sound that has been input, so that it can cope with it as if it had been typed. Highly sophisticated voice recognition software is required for this form of data input.
Scanner - When a light source is passed over a document/image the shape of the characters/image is determined and they are converted into binary code that the computer can understand. Typed documents may be scanned into a computer, and by using Optical Character Recognition software (OCR) this scanned image can then be translated into a working file that can be tidied up and amended.
Digital Cameras - Photographs and video footage can be downloaded/transferred from your digital camera to your computer where they can then be edited and printed using a photography program.
Output devices
An output device is responsible for the transfer of information from the computer to the user.
Visual Display Unit (Monitor) - This is the commonest form of computer output device and can be used for text or graphics. However, there are many different types of monitor, which can be classified by the following:
* Ability to display colours. (Monochrome - two colours, Grey-scale - shades of grey and Colour - 16 to over 1 million different colours)
* Size, which is measured diagonally in inches with the average monitor size being 14 inches.
* Resolution, which indicates the number of pixels or 'picture elements' on the screen. The more pixels a screen has the clearer the picture will appear.
Speakers - Most computers have speakers to enable you to listen to as well as view media on your computer. Speakers can come in different sizes and at different prices depending on the quality of sound you require.
Printers - Computer output can be permanent by printing it on paper. This is called a printout or hardcopy. There are many different types of printer.
* Laser Printers - A laser printer prints a whole page at a time therefore, they are usually expensive but high quality and fast. They work by feeding paper from the tray into the machine and feeding an electrostatic charge across the surface. The laser beam then quickly traces the computers output (text or graphics) as a pattern of tiny dots, which removes the electrostatic charge from the points the laser falls upon. The paper is then sprayed across the surface with a fine layer of ink, which sticks to the points with no charge but is washed off the rest. Laser printers come in black and white as well as colour and give a very high quality print, which is suitable for producing business letters and reports as well as graphics. I would say the disadvantages of this type of printer are its size and also the price. Laser printers are the most superior in terms of print quality, speed and resolution.
* Dot Matrix Printers - These are reasonably priced simple printers. Each character is formed by a pattern of closely spaced dots. The dots are produced by fine needles, which are arranged in a matrix. By choosing needles so that they stand out from the rest the computer can make the shape of a letter, which is then transferred to the paper via an ink ribbon. Dot matrix computers operate at a speed of about 200 characters per second. Although these printers are relatively fast, they do not produce high quality prints, so should therefore be used when ...
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* Dot Matrix Printers - These are reasonably priced simple printers. Each character is formed by a pattern of closely spaced dots. The dots are produced by fine needles, which are arranged in a matrix. By choosing needles so that they stand out from the rest the computer can make the shape of a letter, which is then transferred to the paper via an ink ribbon. Dot matrix computers operate at a speed of about 200 characters per second. Although these printers are relatively fast, they do not produce high quality prints, so should therefore be used when a large amount of printing is required but the quality is not too important a factor. Another important factor to consider if you were planning on buying a dot matrix printer is the amount of noise they make, as they are considerably noisy.
* Ink Jet Printers - Similar to dot matrix printers, the shapes of characters are made up of lots of tiny dots. The dots are made by very fine ink jets that are directed at the paper. The quality of the print is higher than that of dot matrix printers but not a good as laser printers, as the resolution is not as high. Therefore, they are priced somewhere in-between the two. These printers are also a lot quieter than dot matrix printers as there is no impact between the printer and the paper. Ink jet printers come in colour as well as black and white and are consequently the printers that are most suitable for use within the home.
Backing Store (Memory)
The power of a computer is related to its ability to store and retrieve information. The more memory a computer has, the more information it can process. Computers can store data in chips inside the main processor (memory) or on other media such as hard drives and floppy disks. There are two types of memory:
ROM (read only memory) - ROM is held on a chip inside the processor and is used to hold data that cannot be changed by the user. Programs are stored on the ROM chips when a computer is built. As the data is permanently stored on ROM it remains stored even when the computer is switched off.
RAM (random access memory) - RAM is held on a chip but is temporary data. This means that when the computer is switched off it disappears. RAM is used to hold both data and programs during processing.
Hard disks drive - The hard disk is usually stored inside the computer although they can also be removable. They are used to store the operating system, applications software and data files. Hard disks are able to store far more data than floppy disks and access is also much faster. Hard disks can be many sizes from 1 Gb up to 100 Gb(s).
Floppy Disk - Floppy disks come in two sizes, 3.5 inch (known as a diskette) and 5.25 inch. Although the smaller floppy disk is in a hard case the disk inside is floppy. Both disks store binary data as a magnetic pattern on the disks surface. A typical 3.5 inch disk holds 1.44 MB of data. Before data can be stored on a disk it must be formatted. This creates a magnetic map of the disk surface so that data can be either read from the disk or written onto the disk quickly. Because of their high speed to access stored data, floppy disks are probably the most common way of storing data.
Software
Software is the name for all of the programs that are needed to run the hardware. Without software the hardware would be useless. A software package is a program or set of programs together with a full set of documentation. Software programs are usually one of two types: Systems programs or applications.
Systems programs - A systems program is one of the programs that controls the computer system or provides facilities. Computer manufacturers often supply systems software when you purchase your computer. Utility programs and the operating system are both examples of systems programs.
Operating systems - A computer is a complex assembly of different components. These components include processing and memory chips, input and output devices and backing stores. All these components have different functions and run at different speeds. The operating system is responsible for the co-ordination of all the components so that the computer as a whole works efficiently. It also provides the communication between the computer and the user enabling the computer to be used in the most efficient way possible. The operating system also allocates memory space to programs and shares processor time among them.
Applications packages - An applications package is a complete program, or set of programs, to carry out a task such as stock control or wage calculations. Applications packages can be bespoke (made to order) or off the shelf (ready made).
Bespoke - Bespoke application packages are custom made or designed for an individual or company such as an information system for a large insurance company. Bespoke packages are widely used in the business world because they provide an efficient way of working as they can be tailored to specific goals and requirements. However, this type of applications package is very expensive and requires professional programmers to create it and possibly support staff to be on hand in case of any problems.
Off the shelf - Off the shelf application packages are those that can be bought and are ready to use as soon as they have been installed on your computer. They are relatively cheap to purchase compared to bespoke packages and can be customised to meet requirements. There is a wide range of off the shelf packages available and they can be used to carry out a huge number of tasks.
Review of MusicMatch Jukebox
MusicMatch Jukebox is a software package, which enables you to listen to and record MP3's. The basic package can be downloaded from the Internet for free and the plus package can be purchased for around £15. MusicMatch is frequently updating its software and updates can be downloaded free of charge.
When you first install MusicMatch it gives you the option of searching through your hard drive and putting all of the MP3's into the music library. This I found to be a useful feature that other MP3 packages do not usually have. You can also classify all of your music as each MP3 can be given a tag, which includes the artists name, song title, album and genre. MusicMatch will even connect to the Internet to look up the tags for you. This facility enables you choose a particular genre and let the computer select the music for you. MusicMatch also makes the recording of MP3's very easy and also relatively fast.
However, I have discovered that MusicMatch isn't without problems one of which is the annoying fact that it always try's to connect to the Internet and it is slightly confusing to use. It has no real music download (from the Internet) facility therefore the only time I use the Internet with this package is for listening to the radio. Finally, there is also no audio equaliser, which I think would be a nice addition to the package.
Review of Windows Media Player
Windows media player can be used for playing, recording and organising multimedia on your computer. It can be used to listen/record MP3's, watch films and listen to the radio on the Internet. It can support many different file formats including: Real Audio, Real Video, MPEG 1, MPEG 2, MPEG 3 (MP3).
Windows Media Player is extremely easy to use as it has the same format as other Microsoft programs, such as MS Word where you go to the File menu and then to Open. Similar to MusicMatch it is capable of searching your hard drive for media files and adding them to your library but unlike MusicMatch it also has a 10-band audio equaliser which I find gives it a much better sound quality.
Windows Media Player usually comes installed on your computer if you have a Microsoft Operating System. If you do not, or you have an older version it can be downloaded for free from the Internet. Windows Media Player also has visual displays that can be played on your screen whilst you are listening to music.
I think that the downside of this package is that you are not able to easily play particular genres or 'moods' of music. Instead you have to compile play lists, which is time consuming. Also, you can only connect to a limited number of radio stations which I think has something to do with it only supporting Microsoft format files.
TASK 2 - What is a computer network? Explain the term LAN & WAN
Computers that are connected over a network make the exchange of information easier and faster. The most basic type of network would be two computers linked together by a cable and communicating with each other.
Local Area Network (LAN) - A local area network is a number of computers connected to each other by a cable in a single location. Local area networks are often used in businesses to allow communication and information sharing between staff and also different departments. The computers can also share resources, such as applications software, printers and fax machines allowing a business to make more efficient use of their hardware and software.
This diagram shows a simple local area network:
There are three roles for computers within a local area network. These roles are determined by the networks configuration and are:
* Clients which use the network
* Peers, which use and provide network resources
* Servers which provide network resources
There are many ways that networks can be configured. The types of computer, the way they are linked and the network technology decide this.
Some networks have a computer that is responsible for dividing the processing tasks, providing security and administration to the network. This computer is called the server and is usually more powerful than the other computers in the network.
A mainframe network consists of a many pc terminals linked to a master computer called the mainframe, where all the processing and most information is stored. Each dumb terminal (as they're called) acts as a window to the mainframe computer. This network configuration might be used in large businesses such as banks or finance companies where there are many users accessing the same database.
A file server network is made up of PC's as well as a server computer. The server is usually responsible for the applications, and information storage whereas the PC's carry out most of the processing.
In a client/server network the computers use the application software from the server computer but the processing of tasks is shared between the client and the server.
In peer-to-peer networking each computer has the same level of access and no one, is handling more of the processing than the others. The computers share applications by accessing each other's hard disks and also share things like printers.
A local area networks physical layout will vary according to the network technology, hardware configuration and surrounding environment. The physical layout of the network is called the topology. There are three main types of topology shown in the following diagram:
Local area network can be linked to each other via telecommunications networks so that they become a wide area network. This enables different branches of the same business to communicate and exchange information swiftly and efficiently.
Wide Area Networks (WAN) - A wide area network links computers in different locations and is usually a connecting link between local area networks. Wide area networks are used in businesses such as banks that need to pass information around the country, between different branches and also the head quarters. WAN's can communicate over telephone lines and also less frequently with satellite links, packet radio or microwave receivers. However, these options are very expensive and are only used where there are no telephone lines available.
This diagram shows a simple wide area network:
TASK 3 - Identify the security measures that need to be implemented to protect computers and the data stored on them.
Security involves more than just protecting a computer from theft. Computers and the data stored on them must be protected from intentional and accidental damage. The following are examples of computer security problems:
* Accidental Loss - Accidental loss can occur quite easily when for example, users delete files to create more space without really knowing what they have deleted. Also, a file can be overwritten if another file of the same name is saved over it. To overcome these problem computers can be set by the administrator to allow limited access to important files such as program files. This is called 'read' only access.
* Unauthorized Access - Certain information held on a computer may be confidential such as trade secrets, financial information and personnel files. Access to this information needs to be limited to only those users that have the authority to view the files. This can be achieved by putting passwords in place to allow the appropriate users to the files/programs they require. If computer users within a company are given login details and each user has a password this will also prevent access to sensitive data from thieves or people attempting to destroy information.
* Theft - Computers are obviously valuable items and therefore need to be protected from theft at all times. To deter against theft computer hardware can be marked so that should it be stolen, it is easily identifiable. However, it is unlikely you would get your computer back if it was stolen so prevention is the most important factor to consider. Computers should be kept in a lockable room ideally with closed circuit television cameras wherever possible.
* Viruses - Nowadays the Internet is widely used both in the business world and at home, which makes us at risk of picking up viruses. It is important to protect a computer from possible viruses that can destroy data and program files held. Anti virus software can be installed on your computer to check all new files for possible viruses before any damage is caused. If you come across an infected file it should be deleted.
* Fire/Natural Disaster - We never know when the unexpected will happen. Therefore it is important to make sure that if something does happen, we are prepared. Data and Programs are very valuable to companies and many would be unable to function without them. To prevent against unexpected loss of data it must be backed up (copied) and then placed somewhere safe such as a safe. Some businesses choose to back up their files every day, which is usually done at the close of business for that day.
TASK 4 - What is the Data Protection Act? Who and what does it protect? What are the principles of the act and what are the possible exemptions?
The Data Protection Act came into force in 1984 and applies to the whole of the European Union. The objective of this important piece of legislation is to enforce a level of control on personal information being held on a computer database.
The Data Protection Act (DPA) aims to protect everybody and applies to those holding sensitive information on computer for any purpose. The Act is enforced by the Data Protection Registrar (DPR) and all computer users must register any sensitive information regarding individuals with the DPR. The DPA is hugely important due to the wide use of computers within today's society. Should personal data get into the 'wrong hands', be changed or held incorrectly, this could have catastrophic consequences for the individual involved.
The Data Protection Act covers what can be called 'sensitive data' such as details of political opinions, religious beliefs, race, ethnic origin, union membership, physical or mental health and criminal records. This information is obviously of a very private nature to individuals and it is important that although there is a need for some of this data to be held there is also a need to maintain a level of personal freedom and privacy. For example,
There are 8 principles that make up the Data Protection Act which are as follows:
* Fairly and lawfully processed - This means that any data and personal information being held must be acquired honestly and from legitimate sources.
* Processed for limited purposes - The information held should only be for the use of fulfilling the requirement stated upon registering the data with the Data Protection Registrar.
* Adequate, relevant and not excessive - This means the data should not exceed the purpose for which it was originally required.
* Accurate - The data held should be correct and up to date.
* Not kept longer than necessary - Data should only be kept for the amount of time that it is required. When data is no longer needed for a specified purpose it should be destroyed/deleted.
* Processed in accordance with the data subject's rights - This means that the data should only be used in a way that is not an infringement of the rights of the individual involved. The data holder is also bound to supply copies of data to the individual upon their request.
* Secure - This means computers holding sensitive data must be held in a safe location with appropriate security measures in place to ensure it is not harmed or stolen.
* Not transferred to countries without adequate protection This means that data must not be passed to countries that do not follow the rules regarding personal data laid out within the Data Protection Act.
There are also some exemptions to the Data Protection Act where computer users do not have to register the data being held with the Data Protection Registrar:
* Recreational use - This means that data held on a home computer regarding personal, family and household affairs does not need to be registered with the DPR. This would include the individual's own sensitive data such as details of medical health or past convictions.
* Preparation of text documents - This exemption means that computer users are allowed to keep data, which will enable them to prepare documents. This would include data held on your home computer that you intended to write in a letter to the individual.
* Accounts/Wages/Purchases/Sales - This means that data held on a computer for the purpose of preparing accounts such as sales and purchase ledgers, salary and pensions does not need to be registered. This includes information passed by an individual to their accountant for the preparation of their accounts.
* Distribution of articles - This means that computer users are permitted to hold data on their computers without registering it if it enables them to forward correspondence to the individual. This would include a list of friend's names and addresses that you intended to send Christmas cards to.
* Sports/Recreational club (not limited company) This exemption enables these types of establishment to hold individuals data without it being registered with the DPA. This will include membership details and possibly your bank details for the payment of the membership.
There are also instances where the Data Protection Agency will release an individuals data but only if it is in the interest of preventing crime, prosecuting offenders, assessing tax or relating to health or social work. The DPA also has access to amend incorrect data, delete data that is no longer permitted to be held and access to pass data to the individual subject upon their request.
BIBLIOGRAPHY
Books
Roger Carter - Information Technology - 2nd edition 1996 - publisher Made Simple Books
James Chellis, Charles Perkins, Matthew Strebe - Networking Essentials Study Guide - 2nd edition 1998 - publisher SYBEX network press
Timothy Cleary - Business Information Technology - 1st edition 1998 - publisher Pearson Education Ltd
Websites
www.pcwebopedia.com
www.dataprotection.gov.uk
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