I.P.I.A. "E. MATTEI"  -  Latina

Computers.

Computers can be classified into three general groups:

mainframes,personal computers and embedded computers.

Mainframes are the largest and fastest computers,with

the biggest storage systems.They can handle more

information and solve more complex problems than any

other type.Some mainframes are used for a single specific

task,such as processing and storing information produced

by large-scale statistical surveys.

Others perform a variety of different tasks.Time-sharing

systems enable hundreds of users to "lo on" a large

mainframe at the same time.The fastest mainframes,called

supercomputers,are used mostly by scientists and engineers

at large scientific installations for major projects,such as

the design of aircraft,yhe study of weather systems or the

analysis of molecules.

Parallel computers are supercomputers which have hundreds

of microprocessor operating at the same,each working on

a separate piece of a program.Personal computers are

used by one person at a time.The largest PCs fin on a

deskotop;other portable models are called notebook

computers (about the size of an A4 notebook) and palmtop,

or handheld,computers,which can be operated while held

in the hand.Some of these machines have only one

microprocessor;others have additional co-processors to

handle special kinds of work for example graphics or

sound co-processors.A number of separate personal

computers may be interconnected,by telephone lines or

other communications cables,to form a network.

A powerful central computer called the server stores all

the network's essential information and distributes

information to its "clients"PCs,which are also called

workstations.Enbedded computers are control.They are

usually single microprocessors in devices such as digital

cameras,telephones and ignition systems.Commercial

airliners and military planes carry embedded computers

that help to control the aircraft.Enbedded computers also

maintain the orbits of satellites and control the movements

of industrial robots and guided missiles.Special "dedicated

computers"can also be found in machines built for one

particular purpose,such as video games units.