Hardware and Software Requirements For an IT system
ACCESS TO HE IN COMPUTING
Unit Title: IT Systems
Hardware and Software Requirements For an IT system
For this assignment we have to produce a report on the types of hardware and software requirements, and their purposes, for an IT system. In the context of this essay I have decided that bullet point form along with brief descriptions and graphics is the best way to present this assignment.
6 STAGE MODEL
Shown above is the six-stage model, showing the processes undertaken by a computer system. Below is what each of my pictures represents:
* Mouse: Input Device
* The Tower: Central Processing Unit
* Monitor: Output Device
* Floppy Disk: Backing Store
* Head: Main Memory
* Telephone: Communications Devices e.g. Internet
Input Devices and Techniques
'Input devices are the means whereby computers can accept data or instructions'
(Heathcott P M, 2000, p 159)
* Keyboard: The keyboard is the most commonly used of all input devices. It can be used for a various number of tasks, form entering programs, to typing documents using a word processor, or entering a persons personal details etc.
* Mouse: The mouse and its variants such as the trackball is well known with all PC users.
* Scanner: A scanner can be used to scan graphical images and photographs, and software can then be used to edit or touch up the images. Scanners can also be used to read typed or hand-writtten documents and this can then be interpreted by using OCR software, which can then export it to a word processor or data file. Scanners can also be used to input large volumes of data on pre-printed forms such as credit card payments, where the customers account number and amount paid are printed at the bottom of the payment slip.
* Web Cam: This transfers images onto the screen. In can be used via the internet for video conferencing or you can even pre-record messages and send them via E-mail.
* Bar Code Reader: Bar codes appear on almost everything we buy, whether it is a new CD or a tin of bins. The pattern of thick thin lines represents the 13 - digit number underneath the bar code. There are four main pieces of information on a bar code.
The first few two or three digits represent in which country the product was registered. The next five digits represent the manufacturer's code. The second group of five numbers represents the product and package size. The last digit is a check digit, which is calculated from the other digits in the code and ensures that the barcode is keyed in or read correctly. A very similar process to that used in the ASCII code where the spare digit is used as the parity.
A Product Bar Code
* Light Pen: A light pen is a device which incorporates a light sensor so that when it is held close to a screen over a character or part of a graphic, the object is detected and can be moved to create or modify graphics.
* Microphone: An input devise for sound recording.
* OMR (Optical Mark Recognition): An Optical Mark Reader can detect marks made in present positions on a form. The most common example of this is the lottery. It is also widely used for marking, multiple choice exams and market research questionnaires.
* OCR (Optical Character Recognition): Light is emitted, bounced back and then received. This is how the OCR reads its characters. The light emitted is in different resolutions depending on the character. OCR is used widely in services such as gas and electricity etc.
* MICR (Magnetic Ink Character Recognition): All banks use MICR for processing cheques. Along the bottom of a cheque the banks sort code, customer account number and cheque number are encoded in special characters in magnetic ink. The amount of the cheque is encoded in magnetic ink when it is handed in at the bank. The cheques can then be processed by MICR devices that read, sort and store the data on disk. MICR has several advantages for processing cheques:
. It is hard to forge the characters
2. The characters can be read even if the cheque is crumpled, dirty or smudged
3. The characters are readable by humans, unlike bar codes
The disadvantage of MICR though is the expense. This is why you don't find many other examples of it being used.
* Swipe Cards: Swipe cards are operated by using a magnetic strip. They are used in credit cards, debit cards, railway tickets, phone cards and many others. The magnetic strip can be encoded with upto 220 characters of data and ...
This is a preview of the whole essay
. It is hard to forge the characters
2. The characters can be read even if the cheque is crumpled, dirty or smudged
3. The characters are readable by humans, unlike bar codes
The disadvantage of MICR though is the expense. This is why you don't find many other examples of it being used.
* Swipe Cards: Swipe cards are operated by using a magnetic strip. They are used in credit cards, debit cards, railway tickets, phone cards and many others. The magnetic strip can be encoded with upto 220 characters of data and other 83% of adults in Britain own at least one card. Unfortunately because there are only 220 characters of data this makes the cards very easy to copy, which is why the strips will eventually, disappear and be replaced by a chip, which is almost impossible to fake. Something slightly similar to the smart card.
* Smart Cards: Smart cards are of a similar appearance to that of the swipe cards, but instead of using the magnetic strip they contain a small 1-millimeter square microprocessor which is stored in the centre of the card. This is then protected by a small gold electrical contact the card can still read information through this.
Unlike the swipe card the smart cards can hold millions of characters of data. In the future banks hope to replace all the swipe cards with a 'Super card' which will also be able to be used to pay for smaller goods such as milk and newspapers without the need to carry cash. This card will almost be unbreakable. In Belgium they already have a similar system working to this it is called the 'Proton Card', which incorporates the use of both magnetic strip and a microprocessor chip for bank withdrawals and payments of small goods.
The Smart Card
* Touch Sensitive Screens: A touch sensitive screen allows the user to touch an area of the screen rather than having to type the data on a keyboard. They are widely used in tourist centres, where tourists can look up various local facilities and entertainment's, in fast food stores such as McDonald's for entering customer orders, in manufacturing, and also bars.
* Digitisers: A digitiser can draw quality illustrations. It has a flat rectangular slab onto which a stylus (anything that terminates in a point) is placed.
Output Devices and Techniques
'The ultimate aim of the computer is to produce useful information, the information that is produced by the computer is in binary digits, we therefore need devices to translate these into a form we can use'
(Corbitt T, 1990, p 11)
* VDU: (Visual Display Unit) The VDU is similar in appearance to the television receiver, an alternative name is the monitor. VDUs have better resolution than TVs and therefore are better for graphical work. It has its own fixed amount of RAM (Random Access Memory) associated with it to store the image being displayed on the screen. So the more RAM it has the better the resolution displayed on the screen. The number of pixels used to represent a full-screen image determines the resolution. Example:
If 1 bit represents each pixel then two colours can be displayed, so to display 256 colours you would need 8 bits (1byte)
It is usually possible to adjust both the resolution and the number colours - if you select a high resolution you won't be able to have as many colours because of the memory available on the VDU
Printers
The results of processing are usually required in printed form. Printers come in all shapes and sizes, there are two main categories of printers:
* Impact Printers which transfer the image on to the paper by applying pressure against a ribbon onto the paper, this transfers ink form the ribbon to the paper forming the image
* Non-impact Printers which produce the image on the paper without any contact.
Impact Printers
* Dot-matrix: The characters on this are formed by dots. The print head contains a number of needles, the more there are of these the better the quality of print. A head with nine needles would take seven horizontal movements to print a character, this printer would be said to have a seven-by-nine-character matrix. In the latest type near letter quality is produced by double printing. The line of type is printed, the head moves back to the beginning of the line, moves down fractionally and then prints the line a second time. This doubles the time taken to print a document. To overcome this more expensive models use twice the number of needles and near letter quality can be achieved with one pass of the head. The dot-matrix can also print out graphics and pictures of a basic quality.
Dot-matrix printers, which can print in colour, are available, these use a ribbon which contains red, green and blue. Coloured output is obtained by repeated printing, repositioning of the paper, print head and ribbon. The dot-matrix can print between 30 and 200 characters per second (cps).
* Daisy-wheel printers: The print head consists of flexible arms extending from a centre hub, the characters are at the tips of the arms. When printing the hub revolves bringing the required character next to the ribbon. Some daisy-wheel printers are bi-directional and the print head can turn in either direction so that quickest possible print time is achieved. The print can be changed so that different font styles can be used. Daisy wheel printers are unable to print graphics unlike the dot-matrix. It is capable of speed ranges 12 to 55 cps.
Non-impact printers
* Thermal printers: These use specially treated paper, which is affected by heat generated by the print head as it passes across the paper. The main advantages are that they are silent and fast, printing 30-120 cps. Disadvantages are that the paper is expensive and that the printed image degrades in time.
* Ink-jet printer: With this type of printer the characters are formed on the paper by spraying it with a stream of ink dots. They are fast, printing 150-270 cps and almost soundless, the quality of print is very good.
A Canon Bubble Jet Printer BJC7000
* Plotters: Plotters are used to produce drawings, diagrams and other types of graphical output. There are two varieties in use, the flatbed plotter which is used where accuracy is important and the drum plotter which is used for business applications. The flatbed type is fixed while the pen moves over the top of the device while the axis moves up and down, whilst the drum variety uses continuous stationery. In both types the pens, under the program control, are moved to the down position, the movement of the pens is then controlled to draw the image. There are from one to six pens, which can be used to output different colours.
There is also the less commonly known graph plotter. This is most commonly seen in use for lie detector tests.
* COM: (Computer Output on Microfilm) The problem of storing information on paper can be considerable in a large business. One way to solve this is to have output from the computer photographed as microscopic images directly onto microfilm. Two methods of storage are used, one put the information onto a roll of 16mm film while the other uses microfiche. Microfiche can store upto 100 pages of A4 on a single piece, to see it you must have a microfiche reader. The most recent examples of this being used is in libraries and in garages for checking car parts.
Data can be stored onto microfilm directly from the computer or off line using magnetic tape as an intermediary store.
* Voice output: The output of the computer can be given in spoken form by using voice synthesisers to transform words stored in the computer into human speech, this is great for disabled people who cannot speak as it allows them to communicate. The user can hear through a loudspeaker.
Secondary device techniques
A permanent, non-volatile form of storage is required by all computer systems to save software and data files. Magnetic tape, magnetic disks, CD-ROM (Compact Disk Read Only Memory), and microfilm are all examples of what is known as secondary storage.
* Floppy disk: The standard 3 1/2" floppy disk is a thin, flexible plastic disk coated in metal oxide, enclosed in a rigid plastic casing for protection. A standard high density disk has a storage space of 1.44 Megabytes.
* Hard Disks: The hard disk used with conventional PCs consists of one or more disk platters, which are permanently sealed inside a casing. Hard disks have a capacity of between 2Gb and 10Gb, though external hard drives can be plugged into the computer to provide extra storage space. For large-scale applications storing huge amounts of data, more hard disks would be used. The disks can be fixed or removable, although the fixed disks are more reliable and have more storage capacity.
Data is stored on the concentric tracks, which are divided into sectors. Data is then stored in one of the sectors so that it minimises the movement of the read-write heads, thereby minimising access time.
* CD-ROM: CD-ROMs can store around 680Mb of data, which is the equivalent of hundreds of floppy disks. CD-ROMs do not transfer data as quickly as the hard disk drive. As the name suggests the disks are read-only memory. Unlike a magnetic disk they are created by burning tiny holes into the surface of the disk, a laser beam is then reflected off the surface of the disk, detecting the presence or absence of pits, which represent the binary digits.
* Worm disks (Write Once, Read Many): These look very similar to the CD-ROM in appearance but are gold rather than silver in colour. These disks can be used to write your own material and are ideal for archiving or storing images or data, which will not be changed. They are popular in the pirate industry because a £5 blank disk can store upto £20 000 worth of software and sell for £50 - £80. They are used by less reputable PC company's which install the software onto the PC so they can charge the consumer more for the package. However because of the competition in the pirate industry at present many of these carry viruses which can cause chaos on the hard drive.
* Magneto-optical disks: Magneto-optical disks integrate optical and laser technology to enable read and write storage. A 5 1/2" disk can store up to 1 Gb. These disks may in future replace current magnetic disks, but at present the technology is still developing and the disks are too expensive, slow and unreliable to be in widespread use.
* Magnetic tape: Magnetic tape was developed in the 1950s and very quickly became the primary means of storing data. The data is stored on magnetic tape in the form of dots of magnetism. It is used widely for archiving past transactions or other data that may be needed again, for example, old news readings that have been collected over a number of years.
* Jaz Drive: Two Gigabytes is a tape drive and a mass storage device mainly used for backing up large files or batches of files i.e. end of day transaction backup for banks or businesses
Software requirements and techniques
Software is the name given to the programs that direct the operation of the computer. It can be divided into two main groups, system software and applications software. System software is the programs required to run the computer system and applications software is the programs required to carry out a particular application such as stock control
Systems software
This is the software that the microcomputer system needs to run. In this group there are three divisions: operating systems, utilities and compilers/interpreters/assemblers.
Operating systems: An operating system is a set of programs that allows the user to perform tasks without having to know how they are done. For example, a user can give a command to save a file on disk without having to know where the file will be stored or how it will be retrieved again.
Applications programs are usually written to work with a particular operating system e.g. Excel will only work with Windows and not with Apple Mac, which has a different operating system.
Utility programs: Utility programs perform common tasks that every computer user will need at one stage or another. They carry out such jobs as formatting and copying disks, deleting files from disks, sorting information into a required order, and to help with the testing of programs that have been written.
Compilers, interpreters and assemblers: These are programs that translate the programming language that is used into a form that the computer can understand. Compilers work by translating the whole of the program from what is known as the source program into the object program which will be in a form that the computer can understand. Interpreters are programs that translate and execute source programs one statement at a time. An assembler is a program supplied by the computer manufacturer that will translate a program that was written in assembly language (low-level programming language) into machine code.
Applications software: In large organisations that have a mainframe or minicomputer we would find that programmers were employed whose job it would be to write the programs for the applications that the organisation wished to have run on the computer, such as payroll, stock control or hospital appointments. The software may be designed specifically for one particular company and written especially for them using a programming language or software such as database management system. Alternatively, the software may be purchased 'off the shelf'.
General purpose software: Most general purpose software is sold as a package, including a CD containing the software. Below is the most common packages that you would find on the market to date:
. Applications: spreadsheets, database, word processing, Desk Top Publishing
2. Presentation: CD based presentations (Power Point, Director)
3. Internet Publishing: web page development software (Front Page, Dreamweaver, Flash)
4. Programming Software: BASIC, Visual Basic, C++, Java, Pascal, HTML
5. Creation and Editing: Photo Shop, Paint Shop Pro, Premier, Coral Draw
6. Utility: Anti-virus, tidy and compression, Doctors. The newer computer systems will have these utilities on them already.
Software such as word processing, spreadsheet and databases is sometimes refereed to as generic software. This means that many of the packages can be made to do many different tasks, and is not specifically for one type of application. The other types of application software such as stock control and payroll as mentioned before are special purpose because they have been designed to complete one particular task.
Conclusion:
I found this assignment very interesting and now feel I have a much sounder understanding off computer hardware and software. I would have liked to incorporate more images into the assignment as reference to each of the products described, but was unable to find all of the
images that I required, and also had problems trying to transfer them from the internet. Apart from this I feel quite satisfied with the overall assignment and hope that I have entered all the data needed and presented it in a clear fashion.
Bibliography
Corbitt T, (1990), Information Technology And Its Applications. Avon, United Kingdom: Bath Press
Heathcott P M, (2000), 'A' Level Computing. Ipswich, United Kingdom: Payne-Gallway Publishers Ltd
References
Corbitt T, (1990), Information Technology And Its Applications. Avon, United Kingdom: Bath Press
Heathcott P M, (2000), 'A' Level Computing. Ipswich, United Kingdom: Payne-Gallway Publishers Ltd
Michael Firmstone Tutor: Del Turney 14/11/01
