Computer System: A computer is a machine that can be programmed to accept data, process data into useful information and store it for later use. A computer consists of hardware and software. The machine is known as hardware. The programs are called software. The processing of input to output is directed by the software but performed by the hardware.
A computer system requires different computer to perform the functions of input, processing, output and storage. These components are as follows:
1. Input Devices
The data that is given to the computer is called input. Input devices are used to input data and instructions into the computer. These devices send this data to the processing unit. Most commonly used input devices are keyboard and mouse.
2. Processing Device
The processor is used to process data. It is also called central processing unit (CPU). It is the brain of the computer. It consists of electronic circuit. CPU interprets and executes program instructions. All computers must have a central processing unit.
Main memory is used to store the input data before processing. It also stores processed data after processing until the data is sent to the output device. The main memory is closely connected to CPU but it is separate from it.
3. Output Devices
The data processed into useful information is called output. Output devices are used to display the result of processing. The most common output devices are monitor and printer.
4. Storage Devices
Storage usually refers to the secondary storage. The main memory stores data and programs temporarily. The secondary storage is required to store data, information and programs permanently. The most common storage devices are floppy disk, hard disk drive and CD- ROM etc.