1. CS 3013 & CS 502 Summer 2006 Week 1 Review and Class Discussion 1 Review (last week) Three important terms Abstraction Concurrency Resource Critical Sections Conflicting updates to a set of variables by concurrent computations Locking mechanism – Peterson’s solution Locking mechanism – TestAndSet

2. CS 3013 & CS 502 Summer 2006 Week 1 Review and Class Discussion 2 Review (continued) Semaphores Abstraction: integer counter and two operations –wait_s –post_s Interrupts A manifestation of concurrency in most computing systems Responses to concurrent activity among devices and with outside world

3. CS 3013 & CS 502 Summer 2006 Week 1 Review and Class Discussion 3 Review (continued) Process (generic concept) Fundamental abstraction of concurrent execution in all OS’s Definition:– … Operations:– start, dispatch, interrupt, suspend, block, unblock, terminate, … Unix and Windows Processes Heavyweight concept Program, data, virtual memory, files, other resources

4. CS 3013 & CS 502 Summer 2006 Week 1 Review and Class Discussion 4 Homework Assignment Can Peterson’s solution be extended to more than two concurrent processes? Class discussion

5. CS 3013 & CS 502 Summer 2006 Week 1 Review and Class Discussion 5 Next topic – Scheduling