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SAAM and ATAM analysis of AOCS. CS294-10 Fall 2000 Jason I. Hong. SAAM Stakeholders. Companies that want to use AOCS Developers Ground Control ESA. SAAM Scenarios. Component needs more than standard allocated time to execute? Potential deadlock if components need locks on resources?
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SAAM and ATAM analysis of AOCS CS294-10 Fall 2000 Jason I. Hong
SAAM Stakeholders • Companies that want to use AOCS • Developers • Ground Control • ESA
SAAM Scenarios • Component needs more than standard allocated time to execute? • Potential deadlock if components need locks on resources? • Ground control outage?
SAAM Scenarios 1. Component needs more than standard allocated time to execute? • Ex. Task needs lots of processing that cannot be split up • Change Scheduler to give everyone more time (larger uniform time slices) • Or change Tasks to declare timing information (non-uniform time slices)
SAAM Scenarios 2. Potential deadlock if components need locks on resources? • Ex. Need to make sure no one else writes data until done • Can tasks maintain state across time slices? • If so, may need locks to avoid race conditions • Locks may introduce possible deadlock • Affects Tasks, no general resource manager?
SAAM Scenarios 3. Ground control outage? • Ex. Faulty ground control • Potential buffer overflow if needs ACK? • Potential lost data if it doesn't need ACK? • Objects write themselves to telemetry, affects these objects
ATAM Quality Attributes • Reliability • Reusability • Efficient
ATAM Analysis • Reliability • Failure detection • Failure recovery • Redundancy • Not clear how redundancy is handled • Look at why satellites failed historically • See how AOCS can help • Are they app-specific problems or general problems that should be in frameworks?
ATAM Analysis • Reusability • Extensible for new sensors • Extensible for new s/w components • Available tools
ATAM Analysis • Efficient • Hard real-time deadlines • Low overhead • What happens with more resources?