1.1.1.2 : Describe the Brief Evolution of Computer

In the evolution of computers there are five generations of computer:

• First Generation (1941 – 1956) is characterised by the use of vacuum tubes. These computers were very large, slow and expensive . They used machine language for computing and could solve just one problem at a time. Examples: Mark I, ENIAC and UNIVAC. 
• Second Generation (1956 – 1963) is characterised by the use of transistors. The use of transistors results in  smaller and cheaper computers and  made computers more  energy efficient. Computers belonging to this generation used punched cards for input. Examples: IBM 305 RAMAC, IBM 1401 and IBM 1602.
• Third Generation (1964 – 1970) is characterised by the use of integrated circuits (IC). IC consists of small transistors placed on silicon chips, called semi conductors. This increased the speed and efficiency of computers. Magnetic storage (magnetic tape and floppy disk) was also used as the storage medium. Examples: IBM System/360 and DEC PDP-8. 
• Fourth Generation (1970 – present) is characterised by the use of Large-Scale Integrated Circuits (LSI) placed onto a silicon chip made up a microprocessor. LSI has developed into Very Large-Scaled Integrated Circuits (VLSI) and Ultra Large-Scaled Integrated Circuits (ULSI). Introduction of microprocessors was the trademark of the fourth generation computers. Examples: HP 2640, Xerox Alto and Apple II.
• Fifth Generation (present & beyond) is based on artificial intelligence (AI). AI is the branch of computer science concerned with making computers behave like humans. AI has several applications such as speech recognition, natural language, expert system, nanotechnology and robotics. AI tasks can be better served by parallel processing. Examples: IBM Deep Blue, Honda Asimo and Sony Aibo.