First Generation Computers :
• Used vacuum tube technology. (Vacuum tube is a fragile glass device that can control and amplify electronic signals.)
• Computers were very large in size and generated lot of heat.
• Speed was measured in milli-seconds.
• Developed many problems and required frequent maintenance.
• Performed at low speed, occupied large space, consumed more power and needed air conditioning.
• Example : ENIAC(Electronic Numerical Integrator and Calculator) computer developed by USA.
• EDSAC (Electronic Delayed Storage Automatic Computer) was another major development; developed at Cambridge University of England; first introduced in May, 1946.
• Advantages : Vacuum tube technology made possible the advent of electronic digital computers and these were the fastest calculating devices of that time.
• Disadvantages : Very bulky and non portable; lot of heat generated and so air-conditioning compulsory; frequent hardware failures and maintenance.
Second Generation computers:
• Developed in late 1950’s.
• Used transistors in place of vacuum tubes. Transistors were smaller, less expensive and generated less heat compared to vacuum tubes.
• Speed measured in micro-seconds.
• Magnetic tapes could be used as medium for storage of data.
• Example : UNIVAC (Universal Automatic computer) was the first commercial business computer
• Example : IBM 1401, IBM 1410
• Advantages : Flaws of first generation computers removed; smaller in size; Faster and more reliable; commercial production easier and cheaper.
• Disadvantages : Air conditioning required; Manufacturing process involved manual assembly
Third Generation computers:
• Developed in mid 1960’s. (1965-71)
• Used LSIC (Large Scale Integrated Circuits) in place of transistors. IC was small and one IC could do the job of hundreds of transistors.
• Computers became smaller and faster
• Speed measured in nano-seconds.
• Magnetic drums used as medium of storage of information.
• Led to development of software (called Operating System) for efficient use of computer.
• Example : IBM-360 series introduced in 1964`
• Advantages : Smaller in size; more reliable and portable; low maintenance cost, lesser power required.
• Disadvantages : Required highly sophisticated technology for manufacturing ICs.
Fourth Generation Computers:
• Introduced in 1970’s
• Used VLSI (Very Large Scale Integrated) Circuits containing thousands of transistors, diodes and registers.
• Roughly more than 30,000 components could be accommodated on one chip of the size of a postal stamp.
• Concept of micro-processors evolved. It is a chip of silicon known as microprocessor chip.
• Could be easily placed on small table
• Price reduced and affordable and became a common equipment in small business establishments.
• Advantages : Size reduced substantially; air conditioning not required; operations much faster; more general purpose; cheapest amongst all previous generations; desktops made available for business/personal use.
Fifth Generation and next generation computers
• Based on ULSI (Ultra large scale integration) technology.
• Will have tremendous processing power and speed.
• Support high degree of artificial intelligence (computers will be able to think and learn and act on their own to some extent)
• Interact with humans in ordinary languages
Advantages : More user-friendly; reduced size; easy to operate; economical and faster; programming much easier and simpler; emphasis shifted to networks and client server technology.
