Once the CPU has executed the program instruction, the program may request that the information be communicated to an output device, such as a video display monitor or a flat liquid crystal display. Other output devices are printers, overhead projectors, videocassette recorders (VCRs), and speakers.
Input/Output Device, in computer science, a piece of hardware that is used for both providing information to the computer and receiving information from it. An input/output device thus transfers information in one of two directions depending on the current situation. A disk drive is an example of an input/output device. Some devices, called input devices, can be used only for input—for example, a keyboard, a mouse, a light pen, and a joystick. Other devices, called output devices, can be used only for output—for example, a printer and a monitor.
Most devices require the installation of software routines called device drivers, which allow the computer to transmit and receive information to and from the device.