Historical development of computers can be traced back to the time human beings were struggling to invent non – electronic tools to simplify arithmetic such as Abacus and Napier bones It is a Chinese counting instrument which dates back to 3000 BC. It has bead-like parts that move along rods. Each bead above the middle bar stands for five units. Each bead below stands for one unit. Napiers bones was developed by John Napier, a scotitsh mathematician in the 17th century. It helps in multiplication and division It was designed by an English mathematician, Charles Babbage in 1832. The engine is recognized as the first real computer and Babbage as the father of computing. These computers are classified into five generations depending on the technology used to develop them. These computers were huge, expensive and often broke down. They were slow compared to today's computers their internal storage capacity was limited. Cards were used to enter data into the computer. They used vacuum tubes or thermionic valves to control internal operations. They were used for payroll processing and billing e.g. IBM 650, Electronic Numeric Integrator and Calculator (ENIAC) and Electronic Discrete Variable Automatic Computer (EDVAC) Vacuum tube technology made possible the advent of electronic digital computer. These computers were the fastest calculating devices at their time. They were too bulky They were unreliable as they broke down easily Had limited memory They generated a lot of heat Consumed a lot of power They used transistors for internal operations and magnetic card as a primary storage medium. They had increased storage capacity compared to first generation. They had great reduction in size and heat generation, increased processing speed and reliability compared to first generation. Examples IBM 1401, Honeywell 200, CDC 1604 etc Were smaller in size compared to first generation They generated less heat They were less prone to hardware failure Required air conditioning to cool them down . Required frequent maintenance Commercial production was difficult and costly These computers used integrated circuits, Integrated circuits consist of thousands of small transistors etched on a semiconductor called silicon chip. They had increased storage capacity, They were smaller in size They emitted less heat Easier to program, use and maintain compared to their predecessors. Examples IBM, System 360, Burroughs B5500 etc They were smaller in size. Were more reliable as they were not breaking down often. They emitted less heat. Maintenance cost was low because hardware failures were rare. They required less power Highly sophisticated technology required for the manufacture of integrated circuit They were costly These computers use large scale integrated circuit (LSIC) and very large scale integrated circuits (VLSIC) in their processor. They have large storage capacity and work at a high speed. Examples are IBM 4300, Burroughs B7700 They are smaller in size because of high component density Generate negligible heat Much faster in computation They are not prone to hardware failure They are portable because of their small size Highly sophisticated technology required for manufacturer of LSI chips. This generation is characterized by the merging of telecommunication with computer technology. Scientists are working on this generation to bring machines with genuine I.Q, the ability to reason logically and with real knowledge of the world. The anticipated computer will have the following characteristics i. It is expected to do parallel processing ii. It's expected to make use of artificial intelligence iii. Superior hardware and software iv. Very small in size v. Connectivity to the internet.