Realtiden

Realtiden, or real-time, refers to systems and processes in which the correctness of an operation depends on both the result and the time at which it is produced. In practice, real-time systems are designed to respond to events within predefined time limits, known as deadlines. Real-time can be classified as hard real-time, where missing a deadline constitutes a system failure, or soft real-time, where late responses are undesirable but not catastrophic; some systems are described as near-real-time, delivering results with very small delays.

Key properties include determinism, predictable latency, and bounded jitter. Achieving these requires specialized hardware and software, such as real-time operating systems (RTOS), priority-based scheduling (fixed or dynamic), and careful resource management. Real-time data processing can be event-driven or time-driven and often relies on guarantees about worst-case execution time and communication delays.

Applications span embedded control (automotive, avionics, industrial automation), robotics, medical devices, telecommunications, financial trading, and multimedia streaming. In these domains, timely processing is essential for safety, performance, or user experience.

Challenges include ensuring reliable deadline guarantees, handling concurrency and resource contention, verification and certification, and balancing cost with strict timing requirements. Real-time concepts also extend to real-time databases and analytics, which provide up-to-date information with bounded delays.

The term is used across languages, including Scandinavian languages where realtid or realtiden describe the same principle of timely processing.