Input/output

Input/output (I/O) is the transfer of data between a computer and external sources or destinations, or between components within a computer. It includes both receiving data and producing or storing results.

I/O device: A hardware component that sends data to a computer, receives data from it, or does both. Devices such as keyboards, displays, and storage drives provide the endpoints for computer I/O.
Input device: A device that sends data or control signals to a computer. Input devices are sources of data entering a computer.
File system: A system for organizing, naming, storing, and retrieving files on storage media. File access turns application requests into storage reads and writes.
Polling: A technique in which software repeatedly checks whether a device or condition is ready. Polling is an alternative to interrupt-driven notification for detecting I/O events.
I/O-bound process: A process whose performance is limited mainly by waiting for input/output rather than computation. I/O-bound workloads spend much of their time waiting for transfers to finish.
Device driver: Software that lets an operating system communicate with and control a hardware device. Drivers translate operating-system requests into device-specific I/O operations.
Output device: A device that presents or transmits data produced by a computer. Output devices turn computer results into signals or perceptible forms.
Network socket: A software endpoint used by programs to send and receive data over a network. Sockets expose network communication as input and output operations.
Synchronous I/O: An I/O method in which a requesting operation waits for its transfer to complete. Synchronous I/O contrasts with methods that let work continue while transfers proceed.
I/O latency: The time between initiating an input/output operation and its completion. Latency often determines responsiveness, especially for small or interactive requests.

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