A computer system consists of hardware and software.

A computer system consists of hardware and software.

A computer system consists of hardware and software. Hardwareis the

equipment, which makes up the computer system. Hardware consists of:

- Input devices such as keyboard, mouse, joystick

- The Central Processing Unit (CPU)

- Output devices such as a printer, monitor, graph plotter

- Backing storage devices such as disc drive, hard drive

- Media such as discs, tapes, paper etc

There is hardware that I used is:

· Mouse

· Keyboard

· Printer

· Monitor

A tracker ball mouse

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A tracker ball mouse is an input device and similar to a mouse but the

ball is set into a cup on the top of the unit. A finger or, on larger

tracker balls the palm of the hand, is used to roll the ball in any

direction. The ball controls the movement of the pointer on the

screen. Buttons on the tracker ball work in the same way as mouse

butons to activate processes on the screen. My alternative of using a

mouse with a tracker ball would be a mouse without a tracker ball.

Benefit:

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* A tracker ball does not require a large flat surface.

Drawbacks:

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* Most people find them a bit fiddly

* Not accurate

* Not quiet

ALTERNATIVE: Mouse without a tracker ball

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The pointer on the monitor screen mirrors the movement of the mouse by

the user's hand. Under the mouse is a ball, which rolls as the mouse

is moved. This movement of he ball causes two shafts to rotate inside

the mouse; one shaft records the movement in the north-south direction

and the other shaft records the east-west movement. When the screen

pointer is over a0n icon or menu selection, the mouse button can be

clicked, double clicked or dragged to activate a process. Some mice

have a small wheel as well as the buttons. The function of the wheel

depends on the software being used on the computer; in a document, it

can allow the user to scroll up and down; in a desktop publishing

package, it might enable the user to zoom in and out of the page. Over

a period of time, the performance of the mouse can deteriorate as the

ball and shafts collect dust and dirt. Some modern mice use a light

beam and detector to register movements instead off the mouse ball.

Many mice now use infrared or wireless links to the computer, which

removes the need to have a connecting cable.

Benefit:

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* It is easy and convenient to use

* It is inexpensive

* Most modern software includes an option to use it.

* It selects a position on the screen more quickly than is possible