EchtzeitSchedulingAlgorithmen

Echtzeit Scheduling, often referenced as Echtzeit Scheduling in German literature, is the branch of computer science and embedded systems that studies methods for meeting timing constraints of tasks. In real-time systems, each task has a deadline and sometimes a worst‑case execution time; the scheduler must ensure that tasks complete within their deadlines under given resource limits. Real‑time scheduling distinguishes hard, firm, and soft deadlines, with hard deadlines requiring strict guarantees.

Tasks are modeled as periodic, sporadic, or aperiodic. Scheduling may be preemptive or non‑preemptive, and it can run on a single processor or multiple processors. Widely used uniprocessor policies include Rate Monotonic Scheduling (RMS), which assigns higher priority to more frequent tasks, and Earliest Deadline First (EDF), which executes the task with the nearest deadline. On multiprocessors, approaches include partitioned scheduling and global scheduling, sometimes with EDF extensions.

Schedulability analysis provides mathematical tests to determine whether deadlines can be met for a given task set, often using utilization bounds, worst-case response-time analysis, or simulation. Real‑time systems must also address synchronization and resource sharing, using protocols such as priority inheritance or priority ceiling to avoid priority inversion, and must account for communication, interrupts, and overhead.

Applications span embedded control systems, automotive and aerospace, robotics, industrial automation, and real-time data processing. Real‑time scheduling is implemented in specialized operating systems and in POSIX real-time extensions (SCHED_FIFO, SCHED_RR, SCHED_DEADLINE). The field intersects with safety standards and quality requirements in critical domains, such as ISO 26262 for automotive safety and IEC 61508 for functional safety.