a portable computer or other type of processing device the general purpose programmable computer typically comprises a central processing unit a storage or memory unit that can record and read information and programs using machine readable storage media a communication terminal such as a wired communication device or a wireless communication device an output device such as a display terminal and an input device such as a keyboard the display terminal can be a touch screen display in which case it can function as both a display device and an input device different and or additional input devices can be present such as a pointing device such as a mouse or a joystick and different or additional output devices can be present such as an enunciator for example a speaker a second display or a printer the computer can run any one of a variety of operating systems such as for example any one of several versions of windows or of macos or of unix or of linux computational results obtained in the operation of the general purpose computer can be stored for later use and or can be displayed to a user at the very least each microprocessor based general purpose computer has registers that store the results of each computational step within the.