SAAM and ATAM analysis of AOCS

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SAAM and ATAM analysis of AOCS

• CS294-10 Fall 2000
• Jason I. Hong

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SAAM Stakeholders

• Companies that want to use AOCS
• Developers
• Ground Control
• ESA

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SAAM Scenarios

1. Component needs more than standard allocated time
   to execute?
2. Potential deadlock if components need locks on
   resources?
3. Ground control outage?

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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)

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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?

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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

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ATAM Quality Attributes

• Reliability
• Reusability
• Efficient

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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?

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ATAM Analysis

• Reusability
• Extensible for new sensors
• Extensible for new s/w components
• Available tools

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ATAM Analysis

• Efficient
• Hard real-time deadlines
• Low overhead
• What happens with more resources?