Types of Computer

3. On the Basis of Model

On the basis of model computer is classified as:

XT (Extended / Extra Technology) Computer
The computers that use 8086, 8088 microprocessor are called XT computers. The time periods for this computer are from 1975 - 1982. XT computers have processing speed of 4.77 MHz and are comparatively slow in speed. These processors are of 4, 8 or 16 bits of word length.

AT (Advanced Technology) Computer
With the development of 80286 microprocessor AT computer were introduced in the field of computers. The processors are of 8, 16, 32 or 64 bits of word length. The computers using Pentium I, Pentium pro & Pentium II are the examples of AT computers. The time periods for these computers are from 1982 - 1995. These computers can run any type of soft wares including text based as well as graphical base and processor speed of these computers is up to 233 MHz.

PS/2 (Personal System / 2) Computer
IBM started manufacturing next model of computer since 1990. This model is called PS? 2 computers. Most of the computers manufactured after 1990 including laptop, belongs to this model. These computers are refinement of AT computers. These computers can run almost all software & programs.

4. On the Basis of Brand

Computer has two world wide brands:

IBM PC
The IBM Personal Computer, commonly known as the IBM PC, is the original version and progenitor of the IBM PC compatible hardware platform. IBM PC is the largest computer manufacturing company establishing USA. The computer manufactures by IBM PC or branded computer. Personal Computer (PC) is the most important type of micro computer system. The micro computer manufactures by IBM Company are called IBM PC. These computers are reliable, durable and have better quality but they are costly.

Apple/Macintosh Computer
All the computers manufacture by apple cooperation, a leading computers manufacturing computer of USA are known as apple/Macintosh computers. The Apple series of micro computers was developed by Steve Wozniak & Steve Jobs in 1976. This used 8-bit microprocessor chips. These computers use their own software and hardware. They are totally different than that of IBM computers, In terms of both hardware and software. For e.g. software developed for apple computer can't run or IBM computers and vice-versa. Similarly, floppy disk formatting in IBM computer can't be recognized by apple Macintosh computer and vice-versa. It is popularly used in desktop publishing (DTP) houses as they provide better quality of graphic output.