inputandoutput

Input and output, commonly abbreviated as I/O, describes the transfer of data between a computer system and external sources or destinations. I/O encompasses data entry, storage, transmission, and display, and it is a central concern in hardware design, operating systems, and application software.

Input devices include keyboards, mice, touchscreens, sensors, scanners, cameras, and audio capture. Software input often means reading from files, network sockets, user interfaces, or inter-process communication channels. Output devices include displays, printers, speakers, actuators, and network transmitters; software output includes writing to files, sending data over networks, or rendering results to a user interface.

I/O is managed through interfaces and drivers. The operating system schedules I/O requests, may buffer data, and uses interrupts or direct memory access to transfer data without CPU intervention. Common hardware interfaces include USB, SATA, PCIe, Ethernet, and display ports.

I/O performance is characterized by throughput (amount of data per time), latency (delay), and IOPS. I/O models include blocking and non-blocking, synchronous and asynchronous, as well as polling versus interrupt-driven I/O. Buffering, caching, and DMA help optimize performance.

In software, standard input/output streams provide a uniform abstraction for reading and writing data, typically through libraries and language runtimes. Data formats, encoding, and error handling influence I/O reliability and efficiency.