RealTime

Real-time refers to computing systems that must complete tasks within strict temporal constraints. In real-time computing, correctness depends on both the result and the time at which it is produced. Systems are typically classified as hard real-time when missing a deadline is a failure, or soft real-time when occasional misses are tolerable.

Real-time systems rely on determinism, bounded latency, and predictable scheduling. They commonly use real-time operating systems (RTOS) and strategies such as fixed-priority preemptive scheduling (rate monotonic) or dynamic earliest-deadline-first scheduling. Effective real-time design involves estimating worst-case execution times, minimizing jitter, handling interrupts, and ensuring safe resource access through priority inheritance and other synchronization mechanisms.

Key applications include aerospace and defense, automotive control systems, industrial automation, robotics, medical devices, telecommunications, and high-speed financial trading. Real-time data processing is also essential for multimedia, virtual reality, and game engines where latency directly affects user experience or system safety.

Challenges include meeting tight timing constraints on common hardware, achieving safety and reliability standards (for example, DO-178C, IEC 61508, or ISO 26262), and integrating real-time components with non-real-time systems. Ongoing advances include multicore real-time scheduling, virtualization with deterministic guarantees, and hardware support for time-predictable execution.