Generation of computers:
First programmable computer was invented by Konard zuse in year 1936 -1938 and was named as Z1. It is considered as first electro mechanical binary programmable computer.
Coming to the generations of computers, following inventions were responsible for development of computers:
- Invention of transistors
- Inventions of integrated circuits
- Inventions of microprocessors
Along with these inventions computers are divided to in 5 generations:
First generation of computers (1946-1955)
Thermic valve technology was used in first generation of computers. Due to use of thermic valve tubes, computers were very large in size and were also not very reliable. These computers had no operating systems and only way to interact with these computers was through machine language. It was developed by engineers of University of Pennsylvania USA in 1946. Computer was so big in size, it was having height around 5.5 meters length 25 meters and weight of 30 Tons. Computer was very slow in speed such that it used to take 3000 microseconds to just multiply two numbers.
It contained over 100000 electronic components including around 18000 vacuum tubes. Because of vacuum tubes replacing the mechanical devices, response time was that small. However major limitation of this computer was that instructions were stored as a part of its circuit. One has to change the wiring in order to change the instructions. Use of this generation computers were limited to the professionals and to the people having knowledge of electronics and logic circuit.
Second generation of computers (1955-1965)
Era of second generation computer starts with the invention of Transistors. Transistors were introduced by scientists Bardeen and Brattain in 1947. These were substitute for vacuum tubes. Problem of burning of filament of vacuum tubes were totally eliminated by this invention.Second generation computers were faster than first generation computers and they were also smaller in size. These computers offered less power consumption and less cost to market.
In second generation computers, magnetic core was used as the primary memory and magnetic disk as the secondary memory. Magnetic cores are rings with diameters of order of 0.508 mm made of magnetic material that can be magnetized in either clock wise or anti clock wise direction.
High level languages like FORTRAN and COBOL were developed during this period which made interaction of humans with computer easier and program writing was also very easy.
Third generation of computers (1965-1975)
Third generation of computers was In nineteen sixties,when transistors gave way to Integrated circuit (IC). An IC is an extremely thin water of highly purified silicon crystals. A single IC contains all elements of electronic circuit including transistors, resistors and capacitors along with the leads.
This generation of computers were very smaller in size as compared to previous generation computers due to small electronic circuits. They had operating systems for easy user experience. These computers offered multitasking to user execute two operations at the same time at very high speed. Cost of computers were also reduced drastically. These computers were affordable and suitable for commercial use. Power consumption was very less compared to previous generation computers.
Fourth generation of computer (1976-1998)
Use of microprocessor chips in mid seventies marked the advent of fourth generation of computers. Medium to very large scale integrated circuit technology packed about 100 000 transistors in a chip. Company Intel corporation in 1971 packed the complete CPU in a single chip. This was known as microprocessor. This led to production of very powerful personal computers. The main advantages of Fourth generation computers are:
- Microprocessor based technology
- Semiconductor memory
- Very small in size
- Highly reliable
- High speed
- Efficient operating system
- Low cost of production
The above features are responsible for development of very powerful personal computers for use in office and homes. Another significant development of this period is the graphic devices.During the period after 1980, efforts have been put up into the system to increase the memory, hard disk space and secondary storage.
Fifth generation of computers (1998 onwards)
During the last years, tremendous progress in the development of computers has been introduced. Efforts are consistently made to increase reliability, speed and also reduce size, cost and power consumption of computers. Recent developments under process are to develop computers with artificial intelligence , Computers are designed such that they understand human voice and interact with users in natural language. These computers are known as fifth generation of computers.