VEST Tool Base Libraries SW OS Middleware Aspects Domain Code HW Infrastructures Product Library Composition Dependency Checks Analysis Configuration Tool Browse Compose Check Analysis Tools Factual Inter-component Aspects General Real- Time Reliability Map to Process Map to HW Dependency Checks Dependency Checks

Perspective/Design Tools Requirements Design/Design Analysis Synthesis/(Components with Analysis) VEST

VEST Underlying Models - Tailored to Bold Stroke Concurrency – Event Channels Scheduling - TAO real-time scheduling service Persistence

Functional code Real-time Fault-tolerance VEST Design schedulers dispatchers real-time aspects fault-tolerant aspects MW lib OS lib App lib HW lib Supplier1 Supplier2 Supplier3 Event Channel Consumer1 Consumer2 E1 E2 E3 ES1 persistent data dispatcher scheduler priority queue Filter/correlation Event Channel supplier threadsdispatcher threads periodic-save thread CPU1CPU2EEPROM Avionics code Middleware OS HW Libraries Select from library Mapping ORB

Task Model and Events N supplier threads {ST i } and events {EV i }: –ST i and EV i has a specified rate ST j M dispatcher threads {DT j } and event-set priority queues {Q j } –One dispatcher thread for each priority queue Filtering Correlation Scheduler push(ev) consumer Event Channel Supplier/POA threads dispatcher threads priority queues Events

RT Schedulability Analysis Integrated schedulability analysis for Bold Stroke –Event suppliers/consumers –Event channels –Persistent service –ORB core Support tailoring Bold Stroke for timing requirements –Select/configure scheduling algorithm –Select/configure dispatching mechanism –Support for inter-processor events Expand scheduling analysis to new situations

Real-Time Scheduling Analysis TimeWiz (RMA) EDF (Stankovic, et. al. Text) Spring Scheduling model TAO RT Sch. Service resources events precedence overheads

RT Scheduling Analysis Ideas EDF with precedence and resources –utilization bounds Hierarchical scheduling with guarantees –critical and essential tasks –based on results in Regehr’s thesis Statistical guarantees –feedback control real-time scheduling

Aspects Defining/understanding language independent aspects –Vanderbilt -> constraints –UVA cross cutting dependency checks –EX: Buffer sizing how to change components –EX: Replication of critical data

Next slide is just for your information You do have something on experiments – I’m sure Doug will ask about that so you may think about it in more depth, e.g., like I have on the next slide (but that is not very deep either)

Longer Term Plans Experiment 1 –modify persistence requirements (example: save rates, redundancy, security levels) –levels of scheduling requirements critical and essential tasks Experiment 2 –add new capability (example: automatic replication, finer grain locking) –levels of scheduling requirements statistical guarantees