Computer: A computer is an electronic machine which manipulates data according to the list of instructions given and these instructions are called program.
History of Computers: There was a device in China named "Abacus" which was used by Chinese as calculator and it has been noted as being an early computer.In 1820, Charles Babbage was the first who conceptualized and designed a fully programmable computer but due to limited resources, the device was never constructed.In The 1930s and 1940s, an American mathematician Howard Aiken developed a powerful and flexible computing machine named "Mark-I" which was built by IBM.
Generations of Computers: There are five generations of modern computers.
1. First Generation Computers (1945-1955): The first generation computers were based on the vacuum tubes. The first operational electronic general-purpose computer ENIAC (Electronic Numerical Integrator and Computer) was built in 1943 by the partnership between the U.S. government and the University of Pensylvania. It consisting of 18,000 vacuum tubes, 7,000 resisters, 1,000 capacitors, 6,000 switches, and 1 million soldered joints.
2. Second Generation Computers (1955-1965): The second generation computers were based on the transistors. The first computer based on the transistors was "Transac S-2000" constructed in 1958.
3. Third Generation Computers (1965-1975): The third generation computers were based on integrated circuit technology. The integrated circuit is a single device that contains many transistors.
4. Fourth Generation Computers (1975-1995): The fourth generation computers were based on the microprocessors. Microprocessors employ millions of transistors on a single chip.
5. Fifth Generation Computers (1995 onwards): The fifth generation computers are based on microprocessors with very large scale integration of transistors also uses the concept of parallel processing.
Applications of Computers: Some of the applications of the computers are as follows.
1. Weather Forecasting.2. Scientific and Education works.3. Advertisement.4. Entertainment.5. Designing.6. Medical ect.
Types of Computers: There are three types of computers as follows.
1. Analog Computers: An analog computer is a type of computer that uses a continuously changeable value of physical phenomena like the voltage, temperature, pressure, etc. These type of computers are widely used in scientific and industrial applications.
2. Digital Computers: The latest generation computers are digital computers. These type of computers operate on binary digits zero (0) and 1. A binary digit is called "bit" and a group of "8 bits" is called "a byte".
1. Hybrid Computers: The combination of analog computers and digital computers are called hybrid computers which converts analog quantity to digital and digital quantity to analog quantity.
Structure of Computer: The structure of the computer can be divided into 4 parts.
1. Input.2. Process.3. Storage.4. Output.