Computer is an electronic device which is made up of different types of devices. These devices are made up of electronic circuits. These devices are input devices, output devices & storage devices. These devices are called Hardware. Hardware is nothing without Software. The set of instructions given to the devices to perform a particular task is called Software. Step by step instructions written to the computer system is called program. E.g. C, C++, JAVA, etc. are some of the programming languages. Now what comes next is the steps performed by the computer system. The steps include :-

• Input
• Storage
• Processing
• Output

Raw data given to the computer system is an input. This function is performed by an Input Devices. E.g. of input devices are keyboard, mouse, joystick, floppy disk, hard disk, CD-Rom, etc. Raw data are stored in the memory unit. There are two types of memory Primary Memory & Secondary Memory. Hence their storage ability differs. This is the most vital part of the system. E.g. of storage unit is RAM, ROM, etc. Processing is performed when the work of storage unit is done. But, the work of storage unit is performed even when the processing is done. The process by which raw data are converted into meaningfull information is called processing. E.g. of processing unit is CPU. Central Processing Unit(CPU) is the nervous system of the computer which consists of both the storage unit, memory unit & processing. Atlast the output unit works. The meaningfull information given by the computer system after processing raw data is called an output. Hence the device which gives us output is called an Output device. E.g. of output devices are Visual Display Unit(VDU) / moniter, printer, plotter, etc.

Here are some important terms to remember:-

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