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Computer Systems There are two main functions to a computer system; The Hardware and the Software. The hardware is the name given to the part of the computer that can be touched. The hardware is the name given to all the devices that makes up the computer system. Some examples of hardware are: Input devices Central processing unit (CUP) Backing store Output devices Hardware is the term used for the parts of the computer you can touch and handle. Hardware is the name given to the devices that make up a computer system. The hardware devices are split into two groups; they are input devices and output devices. Input devices are used to get data into a system. Output devices are used to receive data from the computer. Input Devices Input devices are used to get information or data in to the computer. The ideal input device would be one that would get the information in to the computer accurately with out human intervention; it would also be quite cheap.
Each key acts as a switch, which closes when the key is pressed. Each key has a code, when a key is pressed the code is sent to the central processing unit. The CPU translates this code into an ASCII code (the code that computers use to represent characters on the computer keyboard), which is then used by the computer program. *Mouse A mouse is a device that when it is moved over the desk a cursor on the screen is moved. There is a ball underneath the mouse that rotates when the mouse is moved. Sensors pick up the movement to move the cursor over the screen. A mouse usually has two to three buttons that are used to make selections. *CD-ROM The CD-ROM makes multimedia possible because of it abilities to have a large storage capacity that is needed for photographs and video chips. CD-ROMs have many useful features, including: 1=they are quite easy to handle and durable 2=they can be used for multimedia presentations 3=600 MB of data can be held on one CD-ROM; hundreds of floppy disks would have normally been needed to store that amount of information.
They print at 300 to 600 dots per minute. This improves the quality of the image. * They are quiet when in operation, compared with a dot matrix; the only sound that a laser printer makes is the noise of the cooling fans and the paper moving. * They are equip with cooling trays, for both input and output paper, so this means when they are in operation they do not need to be supervised. *Dot-matrix Dot-matrix printer use tiny pins in regular arrangements that are fired out to hit an inked ribbon that produces a pattern of dots on the paper. Dot-matrix printers are able to print in colour and they can display both text and graphics. They are impact printers, which can print through layers of paper. This means they can produce multi-part stationary. They are the cheapest printers to buy and run. Electrical signals Electrical signals can be sent from one computer system to a main computer system, which is remote from the terminals. Electrical signals can be used to control devices such a0s burglar alarms and central heating systems.
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