- The evolution was started with the first counting device i.e ABACUS
- Charles Babbage - the father of computers, made an engine called Analytical Engine, which has central processor, storage memory and input and out devices.
- MARK - I was made by Professor Aiken, which was the first electro-mechanical computer.
- Von Neumann gave the concept of "stored program computer" that can store the data and instructions at the same time and same place in the memory.
- The first generation computers (1949 - 1955) used thermionic valves for their operations and used machine language to give instructions. Punch cards were used for input and output the data.
- The second generation computers (1956 - 1965) used transistors for operations and high level language to give instructions. Magnetic tapes and disks were used to store data as secondary storage.
- The third generation computer (1966 - 1975) used integrated circuits for operations, which is also known as IC.
- The fourth generation computers (1976 - till now) are using VLSI circuits for operations and Microprocessor are used for programming and manipulations. VLSI - Very large scale integrated circuits.
- The fifth generation computers will be based on Artificial Intelligence.
- The computers are classified in analog, digital and hybrid categories:
1. Digital computers convert data into binary numbers and then process it.
2. Analog computers work with physical characteristics.
3. Hybrid computers work with both digital and analog computers.
- Digital computers are especial purpose computers depend on microprocessor.
- Digital computers are divided into micro, mini, mainframe and super computers.
1. Micro-computers has only single chip component called microprocessor.
2. Mini-computer has large memory and its a multi-user system.
3. Mainframe has been designed to handle large volume of data and information.
4. Super-computer is the most powerful of all computers, designed to work fast.