Computer Mouse

The basic computermouse is an amazingly clever invention with a relatively simple design thatallows us to point at things on the computer and it is very productive.Think of

all the things youcan do with a mouse like selecting text for copying and pasting,drawing,andeven scrolling on the page with the newer mice with the wheel. Most of us use

the computer mousedaily without stopping to think how it works until it gets dirty and we have tolearn how to clean it. We learn to point at thing before we learn to speak,so

the mouse is a verynatural pointing device.Other computer pointing devices include lightpens,graphics tablets and touch screen,but the mouse is still our workhorse.

The computer mousewas invented in 1964 by Douglas Englehart of Stanford University.As computerscreens became popular and arrow keys were used to more around a

body of text,itbecame clear that a pointing device that allowed easier motion through the textand even selection of text would be very useful.The introduction of the

mouse,with the AppleLisa computer in 1983,really started the computer public on the road to relyingon the mouse for routine computer tasks.

How does the mousework?We have to start at the bottom,so think upside down for now. It all startswith mouse ball. As the mouse ball in the bottom of the mouse rolls over

the mouse pad,itpresses against and turns two shafts.The shafts are connected to wheels withseveral small holes in them. The wheels have a pair of small electronic light-

emitting devicescalled light emitting diodes (LED)mounted on either side.One LED sends a lightbeam to the LED on the other side.As the wheels spin and a hole rotates

by,the light beamgets through to the LED on the other side.But a moment later the light beam isblocked until the next hole is in place.The LED detects a changing pattern of

light,converts thepattern into an electronic signal,and sends the signal to the computer throughwires in a cable that goes out the mouse body.This cable is the tail that helps

give the mouse itsname.The computer interprets the signal to tell it where to position the cursoron the computer screen.

So far we have onlydiscussed the basic computer mouse that most of you probably have or have used.Oneproblem with this design is that the mouse gets dirty as the ball

rolls over thesurface and picks up the dirt. Eventually you have to clean your mouse. Thenewer optical mice avoid this problem by having no moving parts.According to theauthor,general computer users need not know how the computer mouse wasinvented.

A.Right

B.Wrong

C.Not mentioned