Computer
Mainframe Computer
Although these are not as powerful as supercomputers, but certainly they are quite expensive nonetheless, and many large firms & government organizations uses these to run their business operations.
Minicomputer
Desktop computers, laptops, personal digital assistant (PDA), tablets & smartphones are all types of _________. The _________ are widely used & the fastest growing computers. These computers are the cheapest among the other three types of computers. The __________ are specially designed for general usage like entertainment, education and work purposes. Well known manufacturers of _________ are Dell, Apple, Samsung, Sony & Toshiba.
Charles Babbage
Father of computer
abacus
First Computer used by Romans
Fourth Generation Computers (1975-Present)
Started with the invention of Microprocessor. The Microprocessor contains thousands of ICs. Ted Hoff produced the first microprocessor in 1971 for Intel. It was known as Intel 4004. The technology of integrated circuits improved rapidly. The LSI (Large Scale Integration) circuit and VLSI (Very Large Scale Integration) circuit was designed. It greatly reduced the size of computer. The size of modern Microprocessors is usually one square inch. It can contain millions of electronic circuits. The examples of fourth generation computers are Apple Macintosh & IBM PC.
First Generation of Computers (1942-1955)
The beginning of commercial computer age is from UNIVAC (Universal Automatic Computer). It was developed by two scientists Mauchly and Echert at the Census Department of United States in 1947. The first generation computers were used during 1942-1955. They were based on vacuum tubes. Examples of first generation computers are ENIVAC and UNIVAC-1.
Supercomputers
The most powerful computers in terms of performance and data processing are the _________. These are specialized and task specific computers used by large organizations. These computers are used for research and exploration purposes, like NASA uses these for launching space shuttles, controlling them and for space exploration purpose.
Minicomputer
Used by small businesses & firms. These are also called as "Midrange Computers". These are small machines and can be accommodated on a disk with not as processing and data storage capabilities as super-computers & Mainframes. These computers are not designed for a single user. Individual departments of a large company or organizations use these for specific purposes. For example, a production department can use these for monitoring certain production process.
Third Generation Computers (1964-1975)
Used the integrated circuits (IC). Jack Kilby developed the concept of integrated circuit in 1958. It was an important invention in the computer field. The first IC was invented and used in 1961. The size of an IC is about ¼ square inch. A single IC chip may contain thousands of transistors. The computer became smaller in size, faster, more reliable and less expensive. The examples of third generation computers are IBM 370, IBM System/360, UNIVAC 1108 and UNIVAC AC 9000 etc.
Second Generation Computers (1955-1964)
Used transistors. The scientists at Bell laboratories developed transistor in 1947. These scientists include John Barden, William Brattain and William Shockley. The size of the computers was decreased by replacing vacuum tubes with transistors. The examples of second generation computers are IBM 7094 series, IBM 1400 series and CDC 164 etc.