1942-1959 FIRST GENERATION
Computers such as ENIAC and UNIVAC represented only the first generation of computers. They used vacuum tubes programming language was machine language and punched cards as inputs, generating a lot of heat and not reliable.
1959-1965 SECOND GENERATION
The second generation of computers began about 1960 when vacuum tubes were replaced by transistors. Although the transistors performed the same function as the vacuum tubes. The second generation of computers was smaller; generated little heat, less expensive and more reliable. They were also powerful and ten times faster than the first generation of computers. One transistor replaced about 40 vacuum tubes, used magnetic tapes for secondary storage. Examples include IBM 7070,7080,ATLAS.
1965-1970 THIRD GENERATION
Third generation of computers used Integrated Circuits (IC). An integrated Circuit or a chip is a miniature electronic circuit that is etched on a piece of silicone about a quarter-inch square. Integrated Circuits were introduced in 1964. The development of IC revolutionized the computer scene. A single IC could take the place of thousands of transistors. Third generation of computers was smaller, more reliable and far more powerful than second generation of computers. Third generation of computers was also cheaper to make than previous ones, as a result more companies could afford computers. Programming languages were developed. Multi programming and time sharing systems were also introduced. Examples include IBM 360 series, ICL 1900 series.
FORTH GENERATION OF COMPUTERS
This generation of computers was characterized with the use of Large Scale Integrations. It offered greater inputs, output, storage and processing capabilities. This generation introduced the use of Laser memory (could store up to 50 billion characters in the space occupied by a postage stamp), and magnetic bubble memory. A magnetic bubble memory can store up to 1 million binary digits. More important are the advancement that have occurred with respect to the software or programs available with these computers High-level user-oriented programming language, multi programming and multiprocessing techniques and data communications were also introduced.
FIFTH GENERATION OF COMPUTERS
Fifth generation of computers is characterized by Artificial Intelligence, Voice Synthesis and Expert Systems. Artificial Intelligence is the ability of the computer to exhibitits behaviors like an intelligent person. An expert system is a specialized computer package which can perform the function of a human expert.