realtimesystemen

RealtimeSystemen are computer and embedded systems designed to guarantee timely behavior by meeting predefined deadlines for tasks. In these systems, the correctness of a computation depends not only on the produced result but also on delivering it within a specified time window. Delays beyond the deadline can lead to system failure, safety hazards, or degraded performance.

Key characteristics include determinism, predictability, and bounded response times. Designers perform schedulability analysis to ensure that, under worst-case execution times and resource contention, all tasks can meet their deadlines. This often involves careful management of interrupts, synchronization, and parallelism.

Real-time systems are commonly classified as hard real-time or soft real-time. In hard real-time systems, missing a deadline is unacceptable and may constitute a failure. In soft real-time systems, deadlines are important but occasional misses may be tolerated without catastrophic consequences. Mixed forms also exist in practice.

Architectures rely on real-time operating systems (RTOS), priority-based scheduling, and isolation of critical tasks. Common algorithms include Rate Monotonic Scheduling (RMS) and Earliest Deadline First (EDF). Techniques such as WCET (worst-case execution time) estimation, mutexes with priority inheritance, and time-based resource budgeting are used to ensure bounded timing.

Applications span automotive control, avionics, industrial automation, robotics, telecommunications, and medical devices. Standards and safety frameworks often play a central role, with examples including ISO 26262, DO-178C, and IEC 61508. The development process emphasizes timing requirements, verification, and formal timing analysis alongside functional correctness.