Generations of Computer - Complete Notes

Generations of Computer - Complete Notes

Introduction of Computer Generation-
The term “Computer Generation” is related to the evolution, change and adaption of new computing technology. Over the past decades the computer has gone through five generations of development. Among these generations, each of the first three lasted for approximately 10 years and the fourth generation covered the life span of 15 years. This is the era of fifth generation of computer. During this entire period, the sharp changes in the hardware and software technologies of computer have occurred.  

First Generation of Computer-

• It was introduced in the year of 1945 and lasted till 1954.
• This generation of computer used vacuum tubes and relay memories which are interconnected by the insulated wires.
• It was built with a single Central Processing System (CPU) that performed serial fixed-point arithmetic using the program counter, accumulator and branch instructions. 
• Disadvantages- 

1. It was very large in size and due to the high price it could be afforded by large organizations. 
2. It produced lots of heat and consumed large amount of electricity. 
3. It was non-portable also.

• Software and Applications- Machine/Assembly Level Languages, Programmed I/O using CPU.
• Representative Systems- ENIAC (Electronic Numerical Integrator And Calculator), IBM 701, UNIVAC, EDVAC.

Second Generation of Computer-

• It was introduced in the year of 1955 and lasted till 1964.
• In this generation of computer, the discrete transistors, diodes and magnetic Ferrite cores, which are interconnected by printed circuits, are used.
• Index registers, floating point arithmetic, multiplexed memory and I/O processors were introduced with it.
• Advantages – It was more reliable, faster and smaller than First Generation of Computer. 
• Disadvantage- It was very costly.
• Software and Applications- High Level Languages (HLL) used with compilers, batch processing monitors, and subroutine libraries.
• Representative Systems- IBM 7090, CDC 1604, Univac LARC.

Third Generation of Computer-

• It was introduced in the year of 1965 and lasted till 1974.
• The computer of third generation used the integrated circuits for both logic and memory in medium and small scale integration and multilayered printed circuits.
• Pipe-lining and Cache memory were introduced to minimize the speed gap between CPU and main memory.
• Advantages-

1. It was more reliable, faster and smaller than the First and Second Generation of Computer.
2. The maintenance cost was less and less heat was generated.

• Disadvantages- It was very costly.
• Software and Applications- Multi-programmed and Time Sharing OS, Multi user applications.
• Representative Systems- IBM 360/370, CDC 6600, PDP (Personal Data Processor)-8.

Fourth Generation of Computer-

• It was introduced in the year of 1975 and lasted till 1990.
• It used Large Scale Integration (LSI) or Very Large Scale Integration (VLSI).
• Pipeline Processing was introduced.
• Core memory was replaced by the Semiconductor Memory.
• Advantages-

1. It became easily available and very cheap.
2. It was faster and more reliable.
3. Concept of Internet was introduced.

• Software and Applications- Multiprocessing OS, special languages, compilers and environments for parallel processing.
• Representative Systems- IBM 3090, VAX 9000, BBN TC2000.

Fifth Generation of Computer-

• It was introduced in the year of 1991 and has been continuing since then.
• VLSI technology was converted into the Ultra Large Scale Integration Technology.
• Microprocessor chips were introduced.
• Artificial Intelligence (AI) s/w was developed. 
• Advantages-

1. It has user friendly interfaces along with the multimedia features.
2. It is the powerful computer available at a cheap rate.

• Software and Applications- Massively Parallel Processing.
• Representative Systems- Intel Paragon, Cray/MPP, Fujitsu VPP500.