Errorsafety

Errorsafety is the property of a system to limit harm, maintain integrity, and continue operation in the presence of faults, mistakes, or unexpected inputs. It is an interdisciplinary concept applied in software engineering, hardware design, industrial control, and human-centered systems, and aims to reduce the likelihood and impact of errors rather than to guarantee their complete absence.

Common approaches include fault tolerance (redundancy, replication, graceful degradation), fail-safe behavior (transition to a harmless state on failure), and robust error handling (validation, exception handling, transactional rollback). In software, related concepts are exception-safety levels (no-throw, strong, basic), defensive programming, and transactional semantics (atomicity and consistency). In hardware and embedded systems, techniques include error-correcting codes, watchdog timers, and hardware redundancy. Human factors are addressed by clear user interfaces, automation that prevents dangerous inputs, and training.

Design principles that support errorsafety include defense-in-depth, least privilege, isolation of critical components, and clear failure modes. Metrics and evaluation methods include fault-injection testing, formal verification for critical subsystems, and reliability modeling. Standards such as IEC 61508 and sector-specific safety standards guide implementation in regulated domains.

Trade-offs often involve cost, complexity, performance, and usability; highly fault-tolerant designs may be more expensive and harder to maintain. Errorsafety complements, but does not replace, practices that prevent errors through good design, testing, and process control.