1. Mutual Exclusion A History

2. Agenda Model Registers History

3. Model Shared Memory Registers Try, Critical, Exit, Non-Critical

4. Registers Assuming atomic registers is not satisfactory. Register Heirarchy Safe Regular Atomic

5. Waiting Requirements Mutual Exclusion DeadLock Freedom Lockout Freedom First-Come-First-Serve R-bounded Waiting

6. Fault Tolerance Requirements Shutdown safe Abortion safe Unannounced death Malfunctioning (Byzantine behavior) Fail safe Self Stabilizing

7. Upper Bounds 1 bit 3 bit N bit N! bit

8. Fast Path Algorithms Lamport’s Fast Mutual Exclusion 7 memory accesses with no contention “Splitter” method Take quick route if possible

9. Local Spin Algorithms Busy waiting looking at local variables only Remote variables more costly Time complexity based on remote accesses

10. Adaptive Algorithms Time complexity is a function of # of contenders Pinnacle of our project Local Spinning Adaptive Algorithms