1.What is computer?
-Computer is an electronic device that is designed to work with Information.The term ‘computer is derived from the Latin term ‘computare’, this means to calculate.Computer can not do anything without a Program.it represents the decimal numbers through a string of binary digits. Computer is an advanced electronic device that takes raw data as input from the user and processes these data under the control of set of instructions (called program) and gives the result (output) and saves output for the future use. It can process both numerical and non-numerical (arithmetic and logical) calculations.
2.Four functions of computer
-The four basic functions of a computer are input, processing, output and storage. Input is the information which is entered into the computer. Processing is performing operations on or manipulating data. Output is the result of the data processing. Storage refers to devices that can retain the data when the computer is deactivated.
-A system of interconnected computers that share a central storage system and various peripheral devices such as a printers, scanners, or routers. Each computer connected to the system can operate independently, but has the ability to communicate with other external devices and computers.
4.Classifications of computer according to 3 devices
– (1) Micro computers: These computers use a microprocessor chip and this chip is used instead of CPU means that this microprocessor chip works as a CPU. These computers are also called personal computers. Two major types of these computers are laptop or Desktop computers. Only one user uses these computers at time that’s why they are also known as personal computers. (2) Mini Computers: These are powerful computer. These computers come into existence in 1960s at that time mainframe computer was very costly. Mini computers were available in cheap prices, so users start using it.
(3) Mainframe Computer: It as a very powerful and large computer. You can get idea of its power as it can handle processing of many users at a time. Terminals are used to connect a user to this computer and users submit there task through mainframe. Terminal is a device which has keyboard and a screen. By using terminal users put inputs into the computer and get the output through screen. (4) Super Computers: As the name “super computer” specifies that these are most powerful computers even than mainframe. Actually, when we optimize a mainframe computer then we get super computer.
5. History of computer
– The word ‘computer’ originally implied a person, who, under instructions from a mathematician, performed mechanical calculations. Mechanical calculating devices such as the abacus were often put to use to aid this process. At the end of the Middle Ages, mathematics and engineering in Europe received a considerable boost, thus leading to the invention of numerous mechanical calculating devices. The technology for clockwork was developed by the early 17th century. The period between the early 19th century and early 20th century saw the development of a number of technologies which would be vital for the development of the digital computer later on. Some examples are the punched card and the valve. Charles Babbage was the first person to design a fully programmable computer as early as 1837.
However, he was unable to actually construct his computer due to a variety of reasons. Analog computers were increasingly used in the first half of the 20th century for a number of scientific computing needs. However, they became obsolete after the development of the digital computer. The first digital computer was the Atanasoff Berry Computer . It used a binary system of arithmetic, parallel processing, a separation of memory and computing functions and regenerative memory. Binary math and electronic circuits – both of which are used in today’s computers – were first used in the Atanasoff Berry Computer. In the 1930’s and 1940’s, newer and more efficient computers were continuously developed. Gradually, they came to possess the key features which are present in modern day computers – digital electronics and flexibility of programming.
Among the more important machines to be developed during this time, the American ENIAC was prominent. It was a general purpose machine, but had an inflexible architecture. Later a far superior technique known as the stored program architecture was developed. It is the foundation from which all modern computers are derived. Throughout the 1950’s, computer design [http://www.online-computers.info] was primarily valve driven. This was later replaced by transistor-driven design in the 1960’s. Transistor-based computers were smaller, faster and cheaper, and hence commercially viable. Integrated circuit technology, adopted in the 1970’s enabled computer production costs to hit a new low, so that even individuals could afford them. That was the birth of the personal computer, as it is known today.
6.Examples of Input,Output Devices:
*Manual- Abacus,Slide rule,Leibiniz’z Calculator,Napier’s bones,Pascal calculator,Babbage’s Analytical engine *Electronic-Unversal automatic computer,Electronic delayed storage automatic calculator,Electronic discrete variable automatic computer,Electronic numerical integrator and calculator,Atanossof-Berry computer *Electromechanical-Automatic sequence controlled calculator,Jacquard’s Loom, Hollerith’s punched-card machine