If different data formats are being exchanged, the interface must be able to convert serial data to parallel form and vice versa. Handshaking should be implemented by the interface using appropriate commands (like BUSY, READY, and WAIT), and the processor can communicate with an I/O device through the interface. The interface must have the necessary logic to interpret the device address generated by the processor.
Typically a CPU communicates with devices via a bus. An I/O algorithm is one designed to exploit locality and perform efficiently when exchanging data with a secondary storage device, such as a disk drive.Īn I/O interface is required whenever the I/O device is driven by a processor. The CPU and its supporting circuitry may provide memory-mapped I/O that is used in low-level computer programming, such as in the implementation of device drivers, or may provide access to I/O channels. Any transfer of information to or from the CPU/memory combo, for example by reading data from a disk drive, is considered I/O. In computer architecture, the combination of the CPU and main memory, to which the CPU can read or write directly using individual instructions, is considered the brain of a computer. A further complication is that a device traditionally considered an input device, e.g., card reader, keyboard, may accept control commands to, e.g., select stacker, display keyboard lights, while a device traditionally considered as an output device may provide status data, e.g., low toner, out of paper, paper jam. From the human user's perspective, the process of reading or seeing these representations is receiving output this type of interaction between computers and humans is studied in the field of human–computer interaction. Similarly, printers and monitors take signals that computers output as input, and they convert these signals into a representation that human users can understand. Mice and keyboards take physical movements that the human user outputs and convert them into input signals that a computer can understand the output from these devices is the computer's input. The designation of a device as either input or output depends on perspective. Devices for communication between computers, such as modems and network cards, typically perform both input and output operations. For instance, a keyboard or computer mouse is an input device for a computer, while monitors and printers are output devices. I/O devices are the items of hardware used by a human (or other system) to communicate with a computer.
The term can also be used as part of an action to "perform I/O" is to perform an input or output operation. Inputs are the signals or data received by the system and outputs are the signals or data sent from it.
In computing, input/output ( I/O, or informally io or IO) is the communication between an information processing system, such as a computer, and the outside world, possibly a human or another information processing system. JSTOR ( November 2019) ( Learn how and when to remove this template message).Unsourced material may be challenged and removed. Please help improve this article by adding citations to reliable sources. This article needs additional citations for verification.