I/O Devices of Computer System

Input-Output Devices

            A computer system can be useful, only when it is able to communicate with its external environment (its users). As shown in Figure1, the input-output devices (abbreviated I/O devices) provide the means of communication between the computer and the outer world. They are also known as peripheral devices, because they surround the CPU and the memory of a computer system. Input devices are used to enter data from the outside world into primary storage, and output devices supply the results of processed data from the primary storage to the users. A wide variety of I/O devices, are now available. For a particular application one type may be more desirable than another. There are some devices, which are used for both input and output functions. The goal of this discussion is to familiarize you with the various types of I/O devices available for computer systems.

  It is important to note even the fastest of the I/O devices is very slow, when computer to the speed of primary storage and CPU. The main reason for this is that the speed of I/O devices in most cases depends upon mechanical movement, and potential for improvement of such devices is limited. It has been difficult to produce I/O devices, which can match the processor and memory speeds, and there is a constant demand for faster and faster I/O devices.