Theoretical Computer Science

The word computer once meant a person who did ―computations‖ or ―Compute‖, but now it almost always refers to ―automated electronic devices‖. Computers can do much more than calculater, however. They are now used in all sorts of ways to better control or automate products and processes.
―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.

A computer has four functions:

Accepts data	Input
Processes data	Processing
Produces output	Output
Stores results	Storage

computer Input Devices List:

Keyboard
Mouse
Joy Stick
Light pen
Track Ball
Scanner
Graphic Tablet
Microphone
Magnetic Ink Card Reader(MICR)
Optical Character Reader(OCR)
Bar Code Reader
Optical Mark Reader(OMR)

computer Output Devices List:

Monitors
Graphic Plotter
Printer

Data Storage Devices.

Data storage is a unique feature of computer. Once we store data in our computer, we can re-open it, copy it or get its printout whenever we like. We can also transfer data to any other computer or memory device. Computer stores data in electronic signals. That is why, a copied data is 100% the same as the original one. We can make so many copies in a short time.