Five generation of computer

The first electronic computer was designed and built at the University of Pennsylvania. It was based on vacuum tube technology that was in use in military radar equipment. Vacuum tubes were used to perform logic operation and store data.

Based on the development of the technologies used to fabricate the processors, memories and I/O units of computers has been divided into four generations.

1) 1st generation (1945-55)
2) 2nd generation(1955-65)
3) 3rd generation (1965-75)
4) 4th generation (1975 to present)

The First generation – In those days assembly language was used to prepare programs, and was later translated into machine language for execution. Basic arithmetic operations were performed using vacuum tube technology. Mercury delay line memory was used at first, and the I/O functions were performed by devices similar to typewriters.

The Second generation - The basic technology change in 2nd generation was the use of transistors replacing the vacuum tube. Magnetic core memories and magnetic tape storage devices were also used.

Higher level languages like Fortran made the preparation of application programs much easier. Also Compilers were used to translate high level language program into assembly language program. Separate I/O processors were developed to operate in parallel with the central processor.

The Third generation - In 3rd generation computers, Integrated circuit technology was used, which resulted in lower-cost and faster processor and memory elements. Other developments like microprogramming, parallelism and pipelining came into existence. Cache memory and Virtual memory were also developed.

The Fourth generation – In the early 1970s, VLSI (Very large Scale Integration) technology was developed. It allowed tens of thousands of transistors to be placed on a single chip. So the complete processor was fabricated on a single chip.

New concepts such as concurrency, pipelining, caches and virtual memories evolved to produce high performance computing systems. Portable notebook computers, desktop personal computers and workstations are the contributions of the fourth generation.

The Fifth generation - These are the computer systems of future, featuring artificial intelligence, massively parallel execution and extensively distributed computers.