Input/Output (I/O) is a term used in computing to describe the communication between an information processing system (such as a computer) and the outside world. It is the methods of transferring or exchanging data between a computer and peripheral devices, such as a keyboard, mouse, printer, disk drive, and monitor. Input is any data or instructions sent from an external source to a computer system, while output is the data provided by the system to an external source.
I/O operations involve transferring data or commands to or from secondary storage devices or peripheral communications devices, such as keyboards and modems. Devices used to carry out I/O operations are known as peripherals, or I/O devices, and they provide the ability for the user to interact with the computer. Commonly used input devices are keyboards and mice, while common output devices are monitors and printers.
There are two main types of I/O operations: synchronous and asynchronous. In synchronous I/O, the processor waits for a response from the external device after the input has been sent, while in asynchronous I/O, the processor continues to execute instructions while the device responds. An example of synchronous I/O is when a user enters text into a word processor; an example of asynchronous I/O is when data is transferred between two different computers.
I/O is an important part of computing because it allows users to interact with a computer system and create meaningful outputs. Without it, computers would be unable to provide useful information or data, or receive instructions from the user.