Depending on the device used, system architecture, processing mode and language used in the computers are categorized in the following five generation. The development of different types of memory devices has given a sequence of development of computers from mainframe to mirocomputers. In the development of computers there is lot of change from 1946 to 1990. This time is divided in different generations by scientists in a conference in 1962.
First Generation (1946 to 1954):
Introduction of the UNIVAC I in 1951 marked the beginning of the first generation. They began to work on the Universal Automatic Computer (UNIVAC) in 1946; so we can considered the duration of first Generation starts from 1946. The computers using vacuum tubes as a memory unit are known as first-generation computers. The vacuum tube consumes a lot of power. The Vacuum tube was developed by Lee DeForest In 1908.
Features:
1. They used valves or vacumm tubes as their main electronic component.
2. They were large in size, slow in processing and had less storge capacity.
3. They consumed lots of electricity and produced lots of heat.
4. Their were not so accurate and reliable.
5. They used machine level language for programming.
6. They were very expensive.
7. Their computing capabilities were limited.
Example: ENIAC, UNIVAC, IBM 650 etc.
Second Generaton (1955 to 1964):
The invention of Semi-conductor transistor had made big revolution in the field of computer. The transistor replaced the Vacuum tube. The second-geration computers used transistor as a memroy unit. A transistor could do the work of 1000 vacuum tubes. Second generation computers are smaller in size. They are more reliable and faster than the first generation computers. Assembly language was used for programming in second-generation computers.
Features:
1. Transistors were used instead of Vacuum Tube.
2. Processing speed is faster than first Generation Computers (Micro Second)
3. Smaller in size (51 square feet).
4. The input and output devices were faster.
Example: IBM 1400 and 7000 Series, Control Data 3600 etc.
Third Generation (1965 to 1947):
By the development of a small consisting of the capacity of the 300 transistors called Integrated Chip (IC). The computers, using ICs are of the third Generatiions . Thy were smaller in size and had higher efficiency in speed and memory capacity. Very soon ICs were replaced by LSI (large Scale Integration), which consisted about 100 components. An IC containing about 100 components is called LSI.
Features:
1. They used Integrated Circuit (IC) chips in place of the transistors.
2. Semi conductor memory devices were used.
3. The size was greatly reduced, the speed of processing was high, they were more accurate and reliable.
4. Large Scale Integration (LSI) and Very Large Scale Integration (VLSI) were also developed.
5. The mini computers were introduced in this generation.
6. They used high level language for programming.
Exmaple: IBM 360, IBM 370 etc.
Fourth Generation (1975 to 1990):
An IC containing about 100 components is called LSI ( Large Scale Integration) and teh one, which has more than 1000 such components, is called as VLSI (Very Large Scale Integration). The computers designed using VLSI, as a memory unit is known as fourth Generation computers. The first microprocessor 8008 was developed by American Compahy (Intel Corporation) in 1971 and in 1974; another more powerful microprocessor 8080 was developed. The microprocessor 8080 was used in early XT computers. Microprocessor based computers fall in fourth generation computer group. VLSI is also called as microprocessor.
features:
1. They used Microprocessor (VLSI) as their main switching element.
2. They are also called as micro computers or personal computers.
3. Their size varies from desktip to laptop or palmtop.
4. They have very high speed of processing; they are 100% accurate, reliable, diligent
and versatile.
5. They have very large storage capacity.
Example: IBM PC, Apple-Macintosh etc.
Fifth Generation (1990-Present and Future):
The fifth-generation computers are under development stage. These computers are being made using microprocessor and will use USLI (Ultra-large-scale integration) chips (BIO-Chips) in the future. Such computers will use intelligent programmingand improved human-machine interfaces. It is estimated that these computers of fifth generation will have an Artificial Intelligence (AI) with a little thinking capacity and they will understand the natural languages like English, Japanese etc.
Features:
1. They are the future computers which will use parallel processor or genetically
engineered bio-chips as their main switching element.
2. They will have Artificial Intelligence (AI) and will be able to understand natural
language.
3. They will have extremely high efficiency and reliability.
