Signaldriven

Signaldriven is a term used to describe systems or components that are driven by asynchronous signals representing external events. In computing, the concept denotes a design where actions are triggered in response to signals rather than through continuous polling. The approach is common in event-driven and reactive architectures and is used to improve responsiveness when events occur irregularly and to reduce unnecessary resource usage.

In POSIX-compatible environments, signal-driven I/O is a specific form of signal-driven programming in which a process receives a signal (such as SIGIO) when input becomes available or the output device is ready. The process then handles I/O asynchronously rather than repeatedly polling. Implementations require careful signal-handler design, since handlers run asynchronously and must preserve data integrity and reentrancy. This model contrasts with polling and, depending on the system, with hard interrupt-driven I/O, which is handled at a lower level.

Beyond traditional computing, the idea of signaldriven behavior appears in sensor networks, control systems, and other domains where subsystems should react to external cues. Advantages include lower CPU usage for idle periods and lower latency for sporadic events; disadvantages include programming complexity and potential nondeterminism due to asynchronous execution. The term is sometimes used informally and its precise meaning can vary by domain.