The four primary functions of hardware are to accept input, process data and provide output and storage. Different types of hardware are available to handle each of these jobs, though some hardware can perform more than one function.
Devices like the keyboard and mouse are input devices that allow the user to enter data into the computer. Once the data is entered, the central processing unit is responsible for turning the data into something useful to the user. Output is then generated for viewing by devices like printers or monitors. If the output is to be stored for later use, a storage device, such as a hard drive or CD, must be used.