Classification of Computer :ACCORDING TO TECHNOLOGY

ACCORDING TO TECHNOLOGY

• Extended Technology (XT) computers
• Advanced Technology (AT) computers
• Personal System Second (PS/2) Computers.

a) Extended Technology or XT

The extended technology computers used 8006, 8008, 8086, 8088 processors. The period of these computers was from 1975 to 1982. These processors had 4.77 MHz clock speed. The processors were all of 8-bit. These computers are outdated now by two reasons: first, they do not support the latest software and the second that they had low processing power as well as low storage capacity.

b) Advanced Technology or AT

With the advent of 80286 computer microprocessors in 1982, Advanced Technology computers were introduced. The processors were of 8-bit and 16-bit. The computers using processors like 80286, 80386, and 80486 are the examples of such computers. Advanced Technology computers' period is from 1982 to 1995. With the features of higher speed and larger memory than the XT computers, they support latest versions of available software.
AT computers may have 80286 SX or 80387 DX, 80486 SX, 80486 DX or even Pentium (80586) processors. The AT computers support Co-processor that enhances the processing speed and capability of the main processor to perform large and computations within a short period.

c) Personal System or PS/2

With the advancement of Processors having high clock speed as well as high storage capacity IBM developed the second generation of personal computers in early 1990s, which used new refined architecture making the computers faster and more powerful than AT computers. The PS/2 processors used VLSI (Very Large Scale Integration) for chip fabrication and their clock speed range from 85 MHz to 1GHz. Generally, PS/2 Computers use 3.5 inch floppy disks and OS/2 operating System. PS/2 computers are widely used in general purpose computation such as word processing, Database Arrangement, Controlling accounts etc.