Generations of Computers :
The first electronic computer was designed and built at the University of Pennsylvania based on vacuum tube technology.
Computers have been divided into five generations according to the development of technologies used to fabricate the processors, memories and I/O units.
❖ I Generation : (1945 – 55) Bulky, vacuum based and costly, used assembly language which was translated to machine level language for execution. These computers were used mainly for scientific calculations. Examples: ENIAC, EDSAC, EDVAC, UNIVAC.
❖ II Generation : (1955 – 65) Smaller than vacuum based computers, but better performance-wise, used transistors instead of vacuum tubes. High level languages such as FORTRAN and COBOL were used. Punched cards continued to be used during this period. Computers, then, were used increasingly in business, industry and commercial organizations. Examples: IBM 7030, Honeywell 400.
❖ III Generation : (1965 – 75) Small Scale Integration and Medium Scale Integration technology were implemented in CPU, I/O processors etc. Faster processors with magnetic core memories that were later replaced by RAM and ROM. This is when microprogramming was introduced as were operating system software. Database management, multi-user application, online systems like closed loop process control, airline reservation, interactive query systems, automatic industrial control, etc. emerged during this period. Examples: System 360 Mainframe from IBM, PDP-8 Mini Computer from Digital Equipment Corporation.
❖ IV Generation : (1975 – 89) Microprocessors were introduced where complete processors and large section of main memory could be implemented in a single chip. CRT screen, laser & ink jet printers, scanners etc. were developed and so were LAN and WANS. C and UNIX were used. Examples: Intel’s 8088,80286,80386,80486 .., Motorola’s 68000, 68030, 68040, Apple II, CRAY I/2/X/MP etc.
❖ V Generation : 1989 to present Computers use extensive parallel processing, multiple pipelines, multiple processors etc. Portable notebook computers introduced. They also started using object oriented languages such as JAVA. Quantum mechanism and nanotechnology available here will radically change computers for all times. Examples: IBM notebooks, Pentium PCs-Pentium 1/2/3/4/Dual core/Quad core. SUN work stations, Origin 2000, PARAM 10000, IBM SP/2.
