Information Technology Coursework Essay Example for Free

Information Technology Coursework examineInput The KeyboardThe keyboard is essentially based on the standard QWERTY keyboard employ by typists. The principal(prenominal) differences ar the additions do by calculating machine manuf get alongurers. The eldest thing to notice is that the keyboard has three main sections. The first section is the main QWERTY keyboard, which has three extra keys. The most important of these extra keys is normally marked ENTER or RETURN. The commemorate key is on the right side of the keyboard and is used to evidence the figurer that you bring on finished type deliver and wish either to move to a fresh empty line or that you want the calculating machine to carry out the typed instruction. The former(a) two additional keys atomic number 18 the ALT and the CONTROL keys (CTRL). These act in the akin way as the shift key on the typewriter and so allow normal keys to have a number of different effects.The second part of the keyboard is the F UNCTION keys. There ar always at least ten and sometimes twelve of these labelled F1 to F10 or F12, which atomic number 18 grouped together on the left of the keyboard or along the top of it. They are used by weapons platforms kindred word processors or spreadsheets to give instructions to the calculating machine. They do not normally produce an effect on the screen merely foundation do in some programs.The third part of the keyboard is the numeric key pad. This is situated on the right of the keyboard and serves two functions. Firstly, to move the arrow and secondly to type numbers into the calculating machine. The keys on the keypad usually contain the numbers 0 to 9, the decimal point and the mathematical symbols. The key marked NUMLOCK is used to tell the computer if the pad is used to enter numbers (NUMLOCK ON) or to move the cursor (NUMLOCK OFF).Input The abstractA mouse is a gubbins, which fuel provide an alternative to the keyboard. The mouse itself has a secon dary evening gown in its base which, when pulled across a smooth surface, moves a special cursor across the screen. This cursor can be used to draw or point and is especially effective in providing an easygoing to use interface for those who have difficulty with keyboards etc.Processing The Central Processing unit within the microcomputer is a tiny silicon chip called the Central Processing Unit or central processing unit this can be regarded as the brain of the entire strategy. With the help of the computers internal memory it executes the instructions in a program by dressing simple logical operations at very full(prenominal) speeds typically an instruction will be performed in millionths of a second.The chip containing the Central Processing Unit or CPU is the place where the computer does its thinking. The CPU processes training by fetching a program instruction stored in the computers memory, executing the instruction and proceeding to the next step in the program. The CPU contains (1) a program counter that tells the CPU where it is in the program. (2) an instruction register that stores the current program instruction. (3) a arrest unit that decodes the circumscribe of the instruction register. (4) entropy registers that store the small units of development the CPU is currently processing. (5) a memory address register that holds the address or memory location of the breeding in its data registers. (6) an Arithmetic and Logic Unit (ALU) that actually performs each small step in the program, and (7) a shape or flags register that reports on the work of the ALU. The size or power of a CPU is immovable by the length of its registers 8-bit processors work on information in 8-bit groups 16-bit processors have registers that hold 16 bits and are twice as fast. 32-bit processors provide even more computing speed, and so on.Internal Memory mob and ROMBecause the central processing unit only works on small pieces of information at a time, the computer needs a way to store information while it is not be processed. Two kinds of silicon chips serve as the computers internal memory. Random Access Memory or ride chips store information temporarily, and the computer can write, read, and erase information on them. RAM chips are erased either time the computer is turned off, so Read Only Memory or ROM chips act as the computers permanent memory they store the instructions the CPU needs when you first turn it on. external Memory Disks and Disk DrivesExternal memory devices like floppy magnetic discs, hard disks, and CD-ROMs store programs and data when the computer is turned off. When a disk is inserted into a disk drive, the computer can read information from it or write new information onto it. Only certain types of CD-ROM can have information written onto them.Output The PrinterPrinters receive electrical codes from the computer and because print the corresponding letter or number on paper. The result is called hard co py. Plotters and some printing machines can even reproduce computer art on paper.Types of PrinterInk Jet PrintersInk jet printers work as their name suggests, by squirting jets of ink onto the paper done tiny nozzles. Ink-jets provide good quality output (on clean 600 dots per inch) at reasonable speed and at relatively low cost.Laser PrintersA laser printer is essentially a photocopier attached to the computer as an output device. Laser printers are capable of noble quality output ( approximately 720 dots per inch), at high speed. They can be bought from as little as around 100.Output Monitors (Visual Display Units)Monitors (V.D.U.s) are the most frequently used output device. The display is transmitted from the computer to the surface of a cathode ray tube, which is rather like a television screen. Slim, flat screen monitors are also available. The display consists of very small phosphorescent dots combined in different patterns to form words, numbers, and pictures. Monitors part in their resolution (clarity), more dots on the screen means a higher resolution exclusively obviously costs more. The range of resolutions are CGA, EGA and the highest resolution VGA.Software Computer ProgramsA program is plain a set of instructions, which the programmer wishes the computer to obey. The computer blindly obeys any instruction which it is disposed it occupy no abilities to determine whether an instruction (so long as it is framed correctly) is the correct instruction for any given situation. Programs tell the computer how to turn the input you provide into the output you want. A program is therefore a detailed set of instructions for performing a particular task. Because you cannot actually reach out programs they have convey known as software package this contrasts with the hardware of a computer system monitors, chips, printers etc. which you can touchSoftware contracts many forms the computer system itself is co-ordinated by a special resident program called an in operation(p)(a) system (you can read more about this program below), programs to carry out specific tasks for the drug user are termed application programs. Stock control, word processing, payroll and accounting functions are typical areas, which are serviced by application programs.Input/output Media Mass StorageFloppy DisksA floppy disk is 3 1/2 inches square. Inside its protective case or sleeve, each floppy disc is a circle of flexible plastic whose surface is coered with magnetic oxide. When you use a disc for the first time, you must use a special program called an operating system to format the disks surface by creating circular tracks divided into pie-shaped spheres. A hole punched near the hub of the disk lets the computer know where the first sector is. A track on each disk stores a directory that tells the computer where to view what information. This means that it can go directly to the correct part of the disk instead of wading through all of it s contents to find the information it wants. A typical floppy disk can store around cc pages of typewritten text, depending on how tightly the information is packed. If pictures are stored on disk, they take up a lot of room. sustenance of Floppy DisksInformation is stored on floppy disk by means of magnetism. The information stored on a disk can be lost if the magnetic surface of the disk is damaged. When handling a disk you must be careful not to bend it or touch the exposed portions. Moisture, extreme temperatures, and exposure to magnetic fields or equipment can also ruin disks. You should keep back-up copies of all important disks to insure that your data will not be lost if a disk is damaged. You can guard against the gap of accidentally writing over and erasing important data and programs by moving the small write-protect notch on the side of the disk. When this notch is closed, a sensor inside the drive prevents the head from writing onto the disk.Hard Disks all told moder n PCs have hard disks, which can store vast amounts of information this varies depending upon their size. Although they operate on the same basic principles as floppies, hard disks spin many times more quickly allowing the read/write head to pass only fr proceedings of an inch over the disks surface. Hard disks are hermetically sealed in special chambers to prevent dust particles from ruining the disks surface.Disk Drives Read/Write HeadsTo use a disk, you place it into a disk drive so that the circular hole in the centre of the disk fits into a cone in the drive. This cone spins the disk allowing all of its sectors to come under a windowpane cut into the sleeve. As the disk spins around, a read / write head moves back and forth over the exposed portion of the disk. The head works like the head on a tape recorder. It reads information on the disk by translating its magnetic fields into electrical signals that are sent to the computer information is written onto the disk when the he ad converts the electrical signals from the computer into magnetic fields on the disks surface.Operating SystemsA computer is really a system of interconnected parts a keyboard or input device internal memory (RAM and ROM) a processor disks and disk drives output devices like a monitor and a printer and, of course, software. A special kind of program called an operating system controls the flow of information amongst these different components. One of its most important jobs is to enable your hardware to understand the instructions of your software. When you buy a computer, you must be sure that its design or architecture is compatible with the operating system for which the software you want is written. The operating system manages the files on your disks and offers utilities such as formatting blank disks, listing the directory of files on a disk, as well as copying, renaming, and deleting files. Sometimes operating systems are permanently installed, but if the operating system i s pre-packaged on a disk, its contents must either be loaded separately into the computer or written onto all(prenominal) disk used, during the formatting process. Windows 95 and Windows 98 are the most mutual operating systems used today.Modems and NetworksWith the help of a modem, your computer can link up and communicate with other computers all over the world. The modem translates the computers language of ons and offs into tones of different frequencies, which are then transmitted across telephone lines. At the receiving end the process is reversed a modem converts tone variations back into the computers digital code. Computer networks are systems of computers relate together in this way they are used to send and receive electronic mail, and to allow small personal computers access to the vast data libraries of freehandedr computers, via the Internet.COMPUTER APPLICATIONSApplication PackagesThese are programs that actually perform the tasks that the user wishes to be done. The tasks are usually so complicated that several programs are required and these are collectively called a suite of programs. Typical examples of applications are Stock Control, Databases, Order Processing, Word Processing, Airline betrothal Systems, Spreadsheets, Viewdata Systems and Point of Sale Systems. Each package will now be discussed in turn, to give a general explanation of what they are, when they are used and for what purpose.Stock ControlA have a bun in the oven control system keeps track of all the stock currently held by the company. The computer is informed through the till when each event is sold. It is then an easy matter to deduct the number sold from the current stock level to give a new stock level. If this level is below a re-order level which again is held by the computer, then the computer can automatically print a re-order letter to the supplier.The number of each item to be supplied is stored and when the supplier delivers, the number of items delivered is added to the amount in stock. Therefore the company, in theory, should never, through its own efforts, make it out of any item of stock and should at all times know how much stock it has, in the warehouse, in storage at a retail outlet and on the shelves. Losses through theft are easily calculated through a manual shelf count, and corrective action to reduce losses can be implemented quickly.DatabaseA database is a store of information make up of records. A record contains information relating to one person or one company and is make up of individual pieces of information called fields. For example, you may create your records having the following fields company name, address, telephone number, point of reference limit, amount owed, payment due etc.When all the information has been entered the database may then be used by searching for particular information, called cross-referencing (e.g. to find out at the end of the month who the company owes cash to and how much, in order to settle their accounts). New information can be fed in and the database is changed (updated) to embarrass the new data, so that it is always up to date. Large databases are best used with static information (remains the same), with new records being added to the end. An example of this type is a Library with records on all the books in stock.The computer operated by the DVLA in Swansea (Driving Vehicle Licensing Authority) might be an example of a large database. Information relating to every motor vehicle in the U.K. is stored on computer and can be sorted or searched to find out, for example, who owns a particular car.Word ProcessingIn word processing a computer behaves like a much enhanced form of typewriter. Facilities are provided for entering, manipulating, storing and retrieving blocks of text. This means that standard letters and lists of names and addresses can be generated separately and then letters to everyone on the list can be printed without retyping the document. The processor retrieves the letter and the first name and address, prints the letter, retrieves the next name and address, changes the information in the letter, prints the next letter and so on.real time SystemsAn example of a real-time system is Airline Booking. This is a system which updates the data immediately it changes. exclusively the concludings in all the booking offices are connected via a telephone line to a large computer in the head office of the company. This is so that information can be accessed immediately and be changed on confirmation of a booking immediately. For example, if you wanted to book a flight, you would feed details into the terminal about the flight, and back would come a message saying perhaps that only two lay remain on that flight. If you then take these fucks by sending that information back, confirmation would take place and then no-one anywhere in the world would be able to book a seat on that particular flight (even if they tried to book on ly ten seconds after you).SpreadsheetA spreadsheet is a special application package, which allows the user to set up tables of information and add up rows and columns which make up the table. They are used mainly for displaying cash forecasts of companies, in the form of a table where all the figures are interconnected. Each intersection of a row and a column is called a cell. The cells are filled with figures and then changes can be made and the spreadsheet calculates all the related cells, alters and reprints them. Figures can be changed and the overall effect on the complete table can be seen immediately.