Graphics: Graphics are computer-generated images, such as pictures or illustrations. The range of graphics software is extensive and you have probably come across images stored in word processing software (e.g. Clipart) and images created on the computer using lines and shapes (e.g. circles, rectangle, or square).
STAGES OF DEVELOPMENT: Before you can design or write a computer program, there are many stages of development that you must go through when doing this process, these are as follow;
- Analysis of the requirement - what does the computer program need to achieve?
- Design of solution.
- Development of the program - probably broken down the into small subprograms.
- Implementation and testing of the program, including training of the eventual users of the program.
- Preparation of documentation, which will include documentation relating to the actual program and documentation for the users (i.e. a users' guide or manual).
- Ongoing maintenance and development of the program.
In this department I will mention these components groups:
- Input
- Output
- Processor
- Storage
- Ports/Cables
Input
An input device is any hardware, which is used to enter data into the computer system.
Chessingtons keyboards are the most common input devices, which are used. They use a QWERTY keyboard, which is the most common type of keyboard. The name comes from the first six letters on the keyboard. They are based on the design of the first typewriters. Each key is connected to a switch, which closes when the key is pressed. This sends a signal to the CPU based on the characters ASCII code.
There is another type of keyboard that is called a Concept keyboard (soft touch keyboard). They are faster but more limited. They are normally used in the food shops and the restaurants around Chessington. Each switch has a symbol on it representing a piece of data stored in the computer like the price. This is designed to meet the needs of the marketing department.
The second most popular piece of hardware used in the marketing department is the mouse. There are two or three buttons. When a cursor is over an icon, menu item or edge of a picture the mouse button can be clicked once or double clicked to give the computer a command. It Can also be held down to drag something over the screen. There is a ball under the mouse that moves across a flat surface. Sensors measure the movements of the balls in two directions and from this the computer can measure the distance travelled. This is used to move the cursor on the screen.
There are other types of mouse’s like a: -
Tracker ball, which works in the same way as a mouse, but the ball is moved by hand so it takes up less space. This is a fiddly method that is not that accurate or quick. The marketing department use this because it is easier to use and more common than the other types of mouse’s. Touch sensitive pad, which look like small screens. You move your finger across the pad, which moves the cursor. They use less space than a mouse but they are easily damaged and not very reliable. The employees in Chessington don’t think its suitable to use.
Little pimples work by putting your finger on them and pushing them in the direction you want the cursor to move. They are very small and not very precise/accurate.
Output
An output device is any hardware used to communicate the result of data processing carried out by the CPU (Central Processing Unit). The most common output device used in the marketing department is a VDU (Visual Display Unit) also more commonly known as a monitor. They are used when visual information is needed. The two ways in which monitors differ are size and resolution. Size is measured in inches across the diagonal of the screen. Most PCs have 17inches and laptops have 12 inches. Resolution changes by the number of pixels/dots, which make up the viewed image on the screen. The two main types of monitors are:
LCDs (Liquid Crystal Display), which are used in laptops and some desktops. This is the monitor, which the department uses most of the time when the employees are working in groups or individually.
CRTs (Cathode Ray Tubes), which are used in PCs. These are the same one’s as used in TVs and can be damaging to the eyes when in long use. The marketing department rarely use this because of the consequences and the after effect.
Another main output device is a printer. This is used to produce a permanent hard copy of the information on paper. There are three types of printers used in the marketing department:
Dot-Matrix Printers also called impact printers, which are the cheapest to buy and operate. The cashiers of shops around Chessington mainly use this in tills. The print head is a template of pins consisting of 9 or 24 arranged in a vertical line or block. Each fibre is formed using a set pattern of some of the pins. The ribbon is a long strip of material with ink on one side. The print head pins push the ribbon on the paper to create a series of dots. The advantages are that it is cheap to buy and operate. The disadvantages are that it is very slow, low resolution and very noisy.
An Ink-Jet Printer costs less than a laser printer but better quality than a Dot Matrix. This is the most common type used by many organisations. The main component is the print head. This has lots of tiny nozzles or spouts through which small jets of ink are sprayed on to the paper. The advantages are good resolution-300 to 600, which means you can print good quality documents, and often in colour. Disadvantages are its can be slow when printing in colour, often less than four pages per minute. It can be expensive to run and the cartridges cost more per page than laser printer cartridges.
Thirdly the Laser Printer that is also called the page printers because the data to be printed is sent to the printer in complete pages, one at a time. This printer is the type of printer output device that Chessintgon mainly uses. They work in the same way as photocopiers. There are four main parts, which are the electrostatic rotating drum that has a negative electrical charge. The laser reflects on to the drum a mirror image of the page to be printed. Where the page hits the drum the negative charge is removed. When the drum passes over the toner cartridge the ink is attracted to the negatively charged areas of the drum. The ink is then transferred on to the printer paper. The fuser unit heats the paper to fuse the ink onto it. The advantages of a laser printer are very high resolution like 600 dots per inch or more meaning they can print high quality documents. They are also very fast by managing to print over 10 pages per minute and also very quiet. The disadvantages though are they are still quite expensive. There are lots of complex parts inside which are expensive to repair. The marketing department can't use continuous or multi-part stationary.
How the CPU controls input and output hardware
This shows how the information from the input (hardware) devices transmits information into the Central Processing Unit (CPU). The Central Processing Unit then processes the given information, organises it and then transmits it to the output devices that display it.
Processor
Storage
The main storage of the computer stores all of the data, which is going to be processed. All of the data is entered from an input device. The data will reside in memory while it is being processed, then it will be joined by the results of the processing, which will be contained until it is to be carried out and transferred to an output device.
ROM (read only memory) holds predefined program instructions that were written onto the ROM permanently during the manufacturing. These instructions are 'non-volatile', which means the instructions are unaffected by loss of power, from the computer.
RAM (random access memory) is possible to read or write to this type of memory but the contents will be deleted when the power is turned off and the data will not been saved. RAM is also used to hold programs such as Microsoft word while they are running - they are held as files on a disk when they are not in use. RAM also holds graphics data, which is shown on the screen, on the VDU.
Ports/Cables
CABLES AND CONNECTORS:
CABLES: The different components of a computer system are connected by the cables.
CONNECTORS: Computers have connection signs to show the person where to put the wire in, e.g. if you were to look behind a tower case you can see the mouse sign to where you put in.
The Control Unit
The control unit (CU) coordinates the work of the whole computer system. It controls the hardware attached to the system by making sure that the command given to the program are activated. It controls the input and output of data, so all the signals go to the right place at the right time and also controls the flow of the data with the CPU.
The Arithmetic and Logical Unit
This is where the computer processes data by either manipulating it or acting upon it. The Arithmetic part does calculations. The Logic part makes decisions.
Immediate Access Store
The (IAS) holds any data and programs needed by the computer when they are being used. The CPU reads data and programs kept on the backing storage that is stored temporarily in the IASs memory.
The Advantages and Disadvantages of using IT
There are different times when to use ICT and when not to. For example when you want to write the same letter to more than one person, it would be ideal to use ICT to do a mail merge on Microsoft Word. If you want to keep permanent records UN damaged then ICT will be the best way.
When not to use ICT will be when you just want to make notes, quick drafts or diagrams. When you are not creating anything permanently, just deciding different ideas.
The Advantages
A computer based filing database system takes up a lot less space than a paper based filing system. Searching for records is a lot easier and quicker. More than one person at a time can access the data if it is a network connection PC. The data is saved/stays in the computers memory and it won't get lost or miss filed. There a fewer staff needed to look after the computer system. Reports can be generated very quickly often by an automated processing routine.
The Disadvantages
Setting up a computer system is very expensive. Big systems in large organisations such as the NHS cost millions of pounds.
Computer systems need to people to maintain and use them. Training costs can be high and the money is wasted if that person leaves.
Computer systems are not perfect, if there is a system failure or a power cut, then the important data may get lost or corrupted.
It can be easy to copy files and so remove confidential information from the system. The system needs to be kept secure from unauthorised users and hackers.
Data Validation and Verification
Data Validation
Data validation checks the data is the correct type. The computer can perform validation automatically while the data is being entered. There are four main data validation techniques: -
Range check - This makes sure that the data is within the specified range for example a percentage is 0% - 100%.
Presence check - This makes sure that important information has been entered for example when a person orders an item online they need to enter their name, address and credit card number or without these it wont allow it to function.
Check digit - This checks that numerical data has been entered accurately
Data type check - This will check to make sure that text has been entered where needed and not numbers for example.
Data Verification
This is different compared to validation because this is making sure the data that has been input is the same as the original data. There are two main verification techniques: -
Proof-reading - is when a person reads the data that has been entered onto the system and compares with the original, any incorrectly entered data will be edited.
Double entry - is when the data is entered by twice by two people. The computer then compares the two versions and any found errors are then corrected.
Problems with data validation are that it only checks that it is the right type and not whether it is accurate or not. Any problems with the verification program could mean other possible mistakes.
Problems with data verification are that double entry is time consuming and can be very expensive. Proof reading is also expensive and doesn't allow for computer error.
Analysis
In my project, I found the hardest thing was trying to create a booking system. That one page took me four weeks, as I had to type the HTML code, edit it and re edit it. Publisher was much easier to adapt to.
There is nothing that I would change to my project as I feel I have done mine the best possible way.
One of my problems was trying to insert a calendar on the site. When I did it I couldn't proportion it correctly. The text wasn't as visible as I would have liked unless I proportioned it to the whole page. In the end I chose to abandon the calendar. None of the layouts suited my task so I had re design/alter the way they had done it. I did a different background and colour scheme. When using HTML it was hard remembering to use the American language to write it in instead of English.
I did like the way that Publisher toolbar menus were easy to use and understand, for example inserting hyperlinks was much easier than in HTML due to the excellent Microsoft Wizard. I chose Publisher as it actually had a web site creating program unlike Microsoft Word.
I thought that this project was good and the way I did it. Next time I do my project I would write out long texts areas in Microsoft Word because it is easier to do alignment, format and spell check the text. I would still use Microsoft Publisher if it was accessible otherwise HTML. I would also try to be more creative next time for example like adding Java features.
