COMPUTER

Computer is a programmable machine. It accept user-supplied data and instructions, store data and instructions perform mathematical and logical operations (i.e., execute the instructions), and output the result according to user specifications. There are two principal characteristics of a computer are:
It responds to a specific set of instructions in a well-defined manner.
It can execute a prerecorded list of instructions (a program).
Modern computers are electronic and digital. The actual machinery -- wires, transistors, and circuits -- is called hardware; the instructions and data are called software.
COMPUTER HARDWAREHardware is refers to the physical devices a computer system. Hence, the input, storage, processing, control and output devices are hardware.There are so many hardware manufactures. The detail of hardware devices and comparison of hardware manufactures is given below.