Table of Contents
What is Computer
A computer is an electronic device that manipulates information, or “data.” It has the ability to store, retrieve, and process data.
Computer is electronic device that provide facility of inserting data, processing on data and display meaningful information.
History of Computers
- Before the 1500s, in Europe, calculations were made with an abacus Invented around 500BC, available in many cultures (China, Mesopotamia, Japan, Greece, Rome etc.).
- In 1642, Blaise Pascal (French mathematician, physicist and philosopher) invented a mechanical calculator called the Pascaline.
- In 1671, Gottfried von Leibniz (German mathematician, philosopher) extended the Pascaline to do multiplications, divisions, square roots: the Stepped Reckoned. None of these machines had memory, and they required human intervention at each step.
- In 1822 Charles Babbage (English mathematician, philosopher), sometimes called the “father of computing” built the Difference Engine.
- Machine designed to automate the computation (tabulation) of polynomial functions (which are known to be good approximations of many useful functions).
- Based on the “method of finite difference”
- Implements some storage.
- In 1833 Babbage designed the Analytical Engine, but he died before he could build it.
- It was built after his death, powered by steam.
System Concept
A system is a group of integrated parts that have the common purpose of achieving some objectives. A system has following three characteristics:
- A system has more than one element.
- All the elements of a system are logically related.
- All the elements of a system are controlled in such a way that the system goal is achieved.
Since a computer is made up of integrated components (input and output devices, storage, CPU) that work together to perform the steps called for in the program being executed, it is a system.
A computer is a device capable of accepting information or data, processing the information, and providing the results as an output.
As computer is a machine, it has no intelligence & is just hardware. Basically computer system is a combination of five elements without them it cannot work.
- Hardware – machine part.
- Software – instructions to hardware to perform a task.
- People – To operate hardware, create software.
- Procedures – It is a set of instructions.
- Data/Information -Data is a raw material, e. unevaluated facts & figures. Information is the processed data.
Computer System Characteristics and Capabilities:
- Speed: Computer is a very fast device. It can perform the task in a fraction of second which a man cannot. While talking about the speed of computer we have to use terms like millisecond(103), microsecond(106), nanosecond(109), picoseconds(1012). The speed of computer is related to the amount of data it must process.
- Accuracy: Computers give us results very accurately. Errors may occur in computer but they are mainly due to human.
- Reliability: As it is a machine it is free from monotony, tiredness, lack of concentration etc. So it can work for hours together continuously without any So it is more reliable than man.
- Versatility: A computer can perform any type of job with accuracy if necessary information & instructions are given to it (one computer can perform various job).
- Memory Capability: A human brain selects what it feels to be important & worth retaining in its And the unimportant details of information are sent back from the mind or forgotten. But this is not the case with computer. They have the total & instant recall of data & also almost unlimited storage capacity (due to secondary storage which is detachable) .Even after several years the information recalled by computer will be as accurate as on the day when stored. Also the information can be retained as long as desired by user.
- Repeatability: It can perform the same task unlimited no. of times with the same accuracy.
Limitations
- GIGO (Garbage in Garbage Out): The inputs to the computer are the data and program instructions. If any of these are wrong, output by the computer will also be If data or instruction entered is wrong, output cannot be correct.
- No I.Q.: A computer is not a magical device. It can only perform tasks that a human being The difference is that it performs these tasks without thinking.
- Computer can’t learn from experiences: They perform same mistakes repeatedly, until corrected by human beings. They are only as good as a man makes and uses them.