GENERATIONS OF COMPUTERS
Using size and features as the bases, computers are classified into various generations. These generations of computers are discussed below:
1. FIRST GENERATION: The first generation computers were bulky in size. They were able to execute hundreds of instructions per second and were expensive as well. They used vacuum tubes as their main components. Machine language is a first generation language, for example EDVAC, UNIVAC etc.
2. SECOND GENERATION: The second-generation computers were smaller in size as compared to the first generation computers. These were capable of executing thousands of instructions per second, with a transistor as its main component. Assembly language is the second generation language in which programs were written using mnemonic codes, for example, PDP (Programmed data processor), PDP1 etc.
3. THIRD GENERATION: The third generation computers were more advanced and used integrated circuits. These computers contained thousands of components per circuit. They were cheaper than second-generation computers. The languages used in this generation were BASIC, COBOL etc. for example, IBM 307 Series, PDP II etc.
4. FOURTH GENERATION: The fourth generation computers used complex circuits like the large-scale integrated circuits called microprocessors or chips, which surprisingly cost less than the third generation computers. These computers were able to execute millions of instructions per second. The languages used in this generation are C++, SQL etc. for example, CRAY 2, IBM 3090/600 Series.
5. FIFTH GENERATION: These computers work on artificial languages (AI) like LISP, PROLOG etc. They use super/ultra large-scale integrated circuits, which is also called parallel processing method. They execute billions of instructions per second, for example, Laptops, Palmtops, PDA (Personal Digital Assistant) etc.