Class Meeting #13: Review

Topics for Today

• Check on progress of gizmo assignment
• Point out complete example of periodic gizmo-driver task using POSIX system calls
• Return and point out posted solutions to homework assignment #2
• Review topics to be covered for exam

Topics for Exam

• Job and task model
  • define and apply terms (e.g., job, task, periodic task, utilization, response time, implicit deadline, relative deadline)
• WCET
  • why is it difficult to determine? what factors may cause exec. time to vary?
• "Predictability" as defined by Liu
  • define completion-time predictability
  • explain practical importance for use of WCET in scheduling analysis
  • which large classes of scheduling algorithms are predictable?
  • can you give an example that is not?
• Clock-driven scheduling:
  • define and use terms: cyclic schedule, frame, minor cycle, major cycle, hyper-period
  • construct a cyclic schedule for a periodic task set
  • explain pro's and con's of clock-driven static scheduling
• Preemptive vs. non-preemptive scheduling
  • define and apply terms "preemptive" and "non-preemptive"
  • explains pro's and con's of preemptive and non-preemptive scheduling
• Preemptive fixed-task-priority scheduling
  • define and use terms: "critical instant", "critical zone", "level-k busy interval"
  • state and apply Critical Instant Theorem for periodic tasks
  • state worst-case response-time equation
  • apply response-time equation, iteratively, to examples
• Rate-monotonic and deadline-monotonic scheduling
  • understand and apply terms: "rate monotonic", "deadline monotonic", "harmonic periods"
  • state and apply optimality results for RM/DM scheduling
    • for harmonid periods
    • for general case
  • state and apply utilization bound

Things for You to Do

• Review for first midterm exam