5 Generations of Computers

 Generation of Computer

First Generation (1946-1954): In 1946 the digital computer using electronic valves (Vacuum tubes) are known as first generation computers. The first 'computer' to use electronic valves i.e. vacuum tubes. The high cost of vacuum tubes prevented their use for main memory. They stored information in the form of propagating sound waves.

Limitations of First Generation Computer

• They used valves or vacuum tubes as their main electronic component.
• They consumed lots of electricity and produced lots of heat.
• Their computing capabilities were limited.
• They were not so accurate and reliable.
• They used machine level language for programming.

First generation

Second Generation (1955-1964): The second-generation computer used transistors for CPU components and ferrite cores for main memory&magnetic disks for secondary memory. They high-level languages such as FORTRAN (1956) & COBOL (1960-1961). Input Output (I/O) processor was included to control I/O operations.

Manufacturing cost was also very low. Thus the size of the computer got reduced considerably.

Features

• Transistors were used instead of Vacuum Tube.
• Processing speed is faster than First Generation Computers (Micro Second)
• Smaller in Size (51 square feet) 
• The input and output devices were faster.

Third Generation (1964-1977): By the development of a small chip consisting of the capacity of the 300 transistors. These Integrated Circuits (IC)s are popularly known as Chips.

A single IC has many transistors, registers and capacitors built on a single thin slice of silicon. So it is quite obvious that the size of the computer got further reduced. Some of the computers developed  during this period were IBM-360, ICL-1900, and VAX-750. Higher level language such as BASIC (Beginners All purpose Symbolic Instruction Code) was developed during this period.

Features

• They used Integrated Circuit (IC) chips in place of the transistors.
• Semi conductor memory devices devices were used.
• Large Scale Integration (LSI) and Very Large Scale Integration (VLSI) were also developed.
• The mini computers were introduced in this generation.
• They used high level language for programming.

Third generation

Fourth Generation (1978-present): An IC containing about 100 components is called LSI (Large Scale Integration) and the one, which has more than 1000 such components, is called as VLSI (Very Large Scale Integration).

It used large scale Integrated Circuits(LSIC) built on a single silicon chip called microprocessors. Due to the development of microprocessor it is possible to place computer's centralprocessing unit (CPU) on single chip. These computers are called microcomputers.

Features

• They used Microprocessor (VLSI) as their main switching element.
• They are also called as micro computers or personal computers.
• They have very high speed of processing; they are 100% accurate, reliable, diligent and versatile.
• They have very large storage capacity.

Fourth generation

Fifth Generation (PRESENT AND FUTURE): 5th generation computers use ULSI (Ultra-Large Scale Integration) chips. Millions of transistors are placed in a single IC in ULSI chips.

64 bit microprocessors have been developed during this period.. Memory chips and flash memory up to 1 GB,hard disks up to 600 GB & optical disks up to 50 GB have been developed.

• Games Playing: Programming computers to play games such as chess and checkers 
• Expert Systems: Programming computers to make decisions in real-life situations (for example, some expert systems help doctors diagnose diseases based on symptoms)
• Neural Networks: Systems that simulate intelligence by attempting to reproduce the types of physical connections that occur in animal brains 
• Robotics: Programming computers to see and hear and react to other sensory stimuli 

Fifth generation