Input and Output devices

Input devices

Some input devices are :

•Keyboards•Track point•Mouse•Barcode reader•Touch screens

keyboards

Advantages:•Most computers come with a keyboard. •People are used to using keyboards to enter data.•A skilled typist can enter data very quickly.

Disadvantages:•It is easy to make mistakes when typing in data.•If you can’t touch type, it can take time to enter data.•Keyboards are not suitable for creating diagrams.

In computing, a keyboard uses an arrangement of buttons or keys, to act as mechanical levers or electronic switches. The keyboards became the main input device for computer.

Track Point

Advantages :•It requires no extra space, since it is inbuilt within the keyboard. Thus , it is ideal were little or no space is available.

Disadvantages:•It takes a practice in order to learn how to coordinate the correct amount of pressure on the track point.

A Track Point, is a cursor control device found in IBM think pad, notebook, computers.

Mouse

A mouse controls a pointer on the monitor. It enables you to control what happens on the screen by moving the mouse on your desktop and pointing, clicking and selecting items on the screen.

Advantages :•Ideal for use with desktop computers.•Works well in conjunction with a keyboard for data entry.•Using a mouse to select items on the screen is faster than using a keyboard.

Disadvantages: •It is not easy to input text while using a mouse. •They need a flat space close to the computer.•Overuse can lead to repetitive strain injurey.

Barcode ReaderBarcode readers are like scanners which use laser beams in order to read barcodes. A barcode reader is used to read the barcode by using a visible red light.

Advantages :•The process of data entry is fast and accurate.•Barcodes can be printed by normal printing methods.•No need to write down the name of the item and its price- all are retrieved automatically.

Disadvantages:•If there is dirt or any marks on the barcode, then the barcode reader may be unable to read it.•Only numbers can be coded.

Touch ScreensA touch screen is an input device because it allows the user to use his/her finger in order to touch the preferred option.

Advantages:•No training is required.•No extra peripherals such as mouse are needed.

Disadvantages:•Not ideal to put in large amounts of data.•Not very accurate.•Only the items already on the screen can be selected.•Not robust-can soon become faulty if misused

Output devices

An example of an output Is a printer but there are different types of printers:

•Character printer : prints one character at a time.•Page printer: prints one page at a time•Line printer: prints one line at a time.

Character printer

In character printers there are different groups such as impact and non-impact. Also there are different types of each groups.

Impact non-impactdot matrix thermalDaisy wheel inkjetGolf ball

Impact printers Golf ball printer : a golf ball printer uses a rotating ball as a head. On the surface of this ball, there are letters and when this ball strikes the ribbon, the character is imprinter on the paper

Daisy wheel printer : the daisy wheel printer uses a wheel as its print head. These are character shapes formed on each spoke of the wheel. The wheel is rotated until the required character is found, and then a hammer strikes the spoke onto the ribbon against the paper

Advantages : Diasdvantages:You can change fonts you have to change wheel to change fonts.Relatively good quality slow noisy no graphics

Impact printersDot matrix printer : the dot matrix printer has a number of pins in its head. These pins are configured in such a way so as to form a shape. These pins hit the ribbon into the paper. Thus, all character are made up of a pattern of dots. The more pins the better the resolution

Advantages : disadvantages:Cheap simple graphicsEasy maintenance low qualityCan print graphics slow noisy

Non- impact printersThermal printer: thermal printers work by heating certain areas of the thermal paper. When this paper passes over the thermal print head, the paper turns black at heated areas, thus producing a printed image.

Inkjet printer : inkjet printers work by placing extremely small droplets of ink onto the paper, thus creating an image/ character

Advantages : disadvantages :Quiet good quality paper neededFast ink may be smudgedCheapGood quality

Page printer

In page printers there is only one group and that is non-impact. In the non-impact group there Is one printer and that is laser printer.

Laser printer : A laser printer is a common type of computer printer that rapidly produces high quality text and graphics on plain paper.

Advantages: disadvantages:High quality of printouts colour laser printers are expensiveFast: they print 1 page at time expensive maintenanceQuiet : no impact

Line printer A line printer has one group : impact printer . The impact printer is divided into two the drum printer and the chain printer.

Drum printer : drum printers use a rotating drum with character shaped on it. This printer also consists of a hammer set, where there Is a hammer for each character position on the line. these hammers hit the paper onto the ribbon and presses it against the drum. This type of printer is used for checking printing.

Line printer Chain printer : chain printers use a chain with character shaped on it. This chain rotates and the hammer strikes the paper onto that character as it passes. This type of printer is commonly used for payroll listing.

Advantages : disadvantages:Fast can’t print graphicsReliableCan handle large volumes of printouts

The end by

kelsey attard 3.2