realtimecapable

Realtimecapable is an attribute used to describe software, hardware, or systems that can operate under predefined time constraints for sensing, processing, and responding to events. It denotes the ability to produce timely outputs in response to inputs, rather than merely correct results. Realtimecapable systems are commonly distinguished by the presence of predictable timing behavior and, depending on the application, by hard, firm, or soft deadlines.

Key properties include deterministic latency, bounded worst-case execution time (WCET), low jitter, and reliable scheduling. Achieving real-time capabilities often requires a real-time operating system or a kernel that supports preemptive scheduling, priority inheritance, and interrupt handling with bounded interrupt latency. Memory management, including fixed-size pools and avoidance of unbounded pauses, is also critical.

Design strategies include using fixed-priority or earliest-deadline-first scheduling, CPU pinning, and lock-free data structures to minimize contention. Time synchronization with precise clocks (for example, IEEE 1588 Precision Time Protocol) and careful I/O handling help preserve determinism. In software, avoiding garbage collection pauses and controller loop design with tight timing budgets are common practices.

Applications span embedded controllers in industrial automation and robotics, automotive and avionics systems, medical devices, financial trading platforms, and real-time multimedia or collaboration tools. The term is often used descriptively rather than as a formal standard, and the level of real-time guarantees is typically defined in system requirements documents.

Evaluation involves defining deadlines, measuring latency and jitter, analyzing WCET, and testing under worst-case conditions. Real-time capability can increase complexity, cost, and power requirements, and may impose certification or safety obligations in regulated industries.

See also: real-time operating system, deterministic system, latency, scheduling, WCET, ISO 26262, DO-178C.