According to act 2002 the Information Technology (IT), "Computer means any electronic,optical, magnetic,or other high speed data processing device or system which performs arithmetical, logical and memory functions by manipulation of electronic, magnetic or optical impulses, and includes all inputs, output, processing, storage, computer software or communication facilities which are connected or related to the computer in a computer system or computer network." A computer is an electronic device, which accepts input, processes it according to a set of instructions provided and generates the desired output. It operates on data. It can store, process and retrieve data as and when desired. Read more about computer generations A computer system is a combination of the following different elements: • Hardware: All physical devices that the computer is made of. • Software: Instructions that tell the hardware what and how to perform. • Data/Information: Data is facts collected and given as input to the computer and information is processed data, i.e, data is processed into useful information.