| Generations of computers |
Period |
Component/ Technology |
| First |
1940 - 1956 |
Vacuum tubes |
| Second |
1956 - 1963 |
Transistors |
| Third |
1964 - 1971 |
Integrated Circuits(IC) |
| Fourth |
1971 - Present |
Microprocessors |
| Fifth |
Present and beyond |
Artificial Intelligence |
1. First generation computers (1940 – 1956):
Vacuum tubes were used in first generation computers. The input was based on punched cards and paper tapes and output was displayed on printouts. The Electronic Numerical Integrator and Calculator(ENIAC) belongs to first generation was was the first general purpose programmable electronic computer built by J. Presper Eckert and John V. Mauchly.
It was 30 – 50 feet long, weight 30 tons, 18,000 vacuum tubes, 70,000 registers, 10,000 capacitors and required 1,50,000 watts of electricity. It requires Air Conditioner. They later developed the first commercially Successful computer, the Universal Automatic Computer(UNIVAC) in 1952.
The mathematician John Von Neumann designed a computer structure that structure is in use nowadays. Von Neumann structure consists of a central processing unit (CPU), Memory unit, Input and Output unit.
The CPU consists of arithmetic logical unit(ALU) and control unit(CU). The instructions are stored in the memory and follows the “Stored Program Concept”.
Colossus is the secret code breaking computer developed by a British engineer Tommy Flowers in 1943 to decode German messages.
2. Second generation computers (1956 -1963):
Transistors, instead of Vacuum tubes, were used in 2nd generation computers hence size became smaller, less expensive, less electricity consumption and heat emission and more powerful and faster. A team contained John Bardeen, Walter Brattain and William Shockley developed this computer at Bell Laboratories.
In this generation onwards the concept of programming language was developed and used magnetic core (primary) memory and magnetic disk(secondary) memory.
These computers used high level languages(high level language means English like statements are used) like FORTRAN (Formula translation) and COBOL(Common Business Oriented Language). The popular computers were IBM 1401 and 1620.
3. Third generation computers (1964 – 1971):
Integrated Circuits(IC’s) were used. IC’s or silicon chips were developed by Jack Kilby, an engineer in Texas Instruments. It reduced the size again and increased the speed and efficiency. The high level language BASIC(Beginners All purpose Symbolic Instruction Code) was developed during this period The popular computers were IBM 360 and 370.
Due to its simplicity and cheapness more people were used . The number of transistors on IC’s doubles approximately every two years. This law is called Moore’s Law, it is named after Gordon E Moore. It is an observation and not a physical or natural law.
4. Fourth generation computers (1971 onwards):
Microprocessors are used hence computers are called microcomputers. Microprocessor is a single chip which contains Large Scale of IC’s(LSI) like transistors, capacitors, resistors etc due to this a CPU can place on a single chip. Later LSI were replaced by Very Large Scale Integrated Circuits(VLSI). The popular computers are IBM PC and Apple II.
5. Fifth generation computers (future):
Fifth generation computers are based on Artificial Intelligence(AI). AI is the ability to act as human intelligence like speech recognition, face recognition, robotic vision and movement etc. The most common Al programming language are LISP and Prolog.
