Overview
ISO/IEC TS 24718:2025 - Information technology - Programming languages - Guidance for the use of the Ada Ravenscar Profile in high integrity systems - provides focused guidance on using the Ada Ravenscar profile to build concurrent Ada software suitable for verification up to the highest integrity levels. The technical specification explains the motivations behind Ravenscar, maps Ada constructs to a deterministic scheduling model, defines the Ravenscar restrictions (including the pragma Profile (Ravenscar)), and supplies worked examples and verification guidance for implementers, developers and certifiers.
Key topics
- Ravenscar profile definition and rationale - a clear description of the language-level restrictions that enable analyzable, deterministic concurrency.
- Scheduling theory and mappings - how tasks, priorities and dispatching map to real-time scheduling models used for analysis.
- Static existence and synchronization models - static task creation, protected objects, entries, and deterministic communication.
- Deterministic memory and execution models - restrictions that eliminate dynamic allocation and unpredictable behaviors at run time.
- Run-time semantics and errors - rules for locking, queuing, task dispatch, and additional run-time error conditions introduced by Ravenscar.
- Verification techniques - static analysis, scheduling analysis (rate monotonic and response-time methods), formal analysis and certification-oriented checks (e.g., Max_Entry_Queue_Length, priority-ceiling considerations, potentially-blocking operations in protected actions).
- Practical examples - cyclic tasks, event-triggered tasks, protected objects, interrupt handlers, coordination patterns, and an extended annotated application example.
Applications and who should use it
ISO/IEC TS 24718:2025 is targeted at:
- Application programmers developing safety-critical Ada systems
- Run-time system implementers and compiler vendors who must support Ravenscar semantics
- Project or company guideline authors creating development rules for high-integrity systems
- Academics and verification engineers studying analyzable concurrency models
Practical uses include safety-critical, real-time embedded systems where deterministic behavior and rigorous verification are required - for example avionics, automotive, medical devices and industrial control systems. Using the Ravenscar profile simplifies static analysis, enables sound scheduling analysis, and supports evidence-based certification.
Related standards
- Ada language standard (ISO/IEC 8652) - Ravenscar is a profile within the Ada language ecosystem.
- Scheduling and verification literature - the specification aligns Ravenscar semantics with real-time scheduling theory and common verification practices.
For engineers building verifiable, deterministic concurrent Ada applications, ISO/IEC TS 24718:2025 is the definitive guidance on applying the Ravenscar profile effectively.