Computer

COMPUTERS

Computer is an electronic device which accepts data as input, performs processing on the data, and gives the desired output. A computer may be analog or digital computer.

1. Speed, accuracy, diligence, storage capability and versatility are the main characteristics of computer.
2. The computing devices have evolved from simple mechanical machines, like ABACUS, Napier’s bones, Slide Rule, Pascal’s Adding and Subtraction Machine, Leibniz’s Multiplication and Dividing Machine, Jacquard Punched Card System, Babbage’s Analytical Engine and Hollerith’s Tabulating Machine, to the first electronic computer.
3. Charles Babbage is called the father of computer.
4. The evolution of computers to their present state is divided into five generations of computers, based on the hardware and software they use, their physical appearance and their computing characteristics.
5. First generation computers were vacuum tubes based machines. These were large in size, expensive to operate and instructions were written in machine language. Their computation time was in milliseconds.
6. Second generation computers were transistor based machines. They used the stored program concept. Programs were written in assembly language. They were smaller in size, less expensive and required less maintenance than the first generation computers. The computation time was in microseconds.
7. Third generation computers were characterized by the use of IC. They consumed less power and required low maintenance compared to their predecessors. High-level languages were used for programming. The computation time was in nanoseconds. These computers were produced commercially.
8. Fourth generation computers used microprocessors which were designed using the LSI and VLSI technology. The computers became small, portable, reliable and cheap. The computation time is in picoseconds. They became available both to the home user and for commercial use.
9. Fifth generation computers are capable of learning and self organization. These computers use SLSI chips and have large memory requirements. They use parallel processing and are based on AI. The fifth generation computers are still being developed.
10. Computers are broadly classified as microcomputers, minicomputers, mainframe computers, and supercomputers, based on their sizes and types.
11. Microcomputers are small, low-cost stand-alone machines. Microcomputers include desktop computers, notebook computers or laptop, netbooks, tablet computer, handheld computer and smart phones.
12. Minicomputers are high processing speed machines having more storage capacity than the microcomputers. Minicomputers can support 4-200 users simultaneously.
13. Mainframe computers are multi-user, multi-programming and high performance computers. They have very high speed, very large storage capacity and can handle large workloads. Mainframe computers are generally used in centralized databases.
14. Supercomputers are the most expensive machines, having high processing speed capable of performing trillions of calculations per second. The speed of a supercomputer is measured in FLOPS. Supercomputers find applications in computing-intensive tasks.
15. Computer is an electronic device based on the input-process-output concept. Input/Output Unit, CPU and Memory unit are the three main components of computer.
16. Input/Output Unit consists of the Input unit which accepts data from the user and the Output unit that provides the processed data. CPU processes the input data, and, controls, coordinates and supervises the operations of the computer. CPU consists of ALU, CU and Registers. The memory unit stores programs, data and output, temporarily, during the processing. Additionally, storage unit or secondary memory is used for the storing of programs, data and output permanently.
17. Computers are used in various areas of our life. Education, entertainment, sports, advertising, medicine, science and engineering, government, office and home are some of theapplication areas of the computers.