timetriggered

Timetriggered describes actions initiated by a time-based condition rather than external stimuli. In computing and automation, timetriggered operations are scheduled to occur at a specific time, after a duration, or at regular intervals.

Implementation relies on timers, clocks, and schedulers. Common technologies include OS timers and cron-like schedulers, programming language libraries that provide delayed or periodic callbacks, and real-time clock sources. Depending on requirements, a timetriggered task may use a monotonic clock to avoid wall-clock changes, or a wall clock with time zone awareness for human-facing schedules. Challenges include clock drift, jitter, daylight saving transitions, and persistent state across restarts.

Applications include operating systems that use timer interrupts to schedule tasks; embedded systems that rely on hardware timers; automation and workflow engines that schedule batch jobs; data pipelines that trigger ETL tasks; and IoT devices that wake and perform actions at set times.

In contrast to event-triggered systems, timetriggered systems respond to time conditions rather than external events. Some architectures, such as time-triggered architectures, emphasize determinism and predictability by enforcing schedule-driven execution.

See also terms such as timer, scheduler, cron, time-driven architecture, and event-driven architecture.