Computer Science 322
Operating Systems

• Announcements
  • CPU simulator deadlines
  • Shell and CPU simulator resubmits
  • Friday's schedule: I will be in Kendade 307 10-12 and 1:30-3 to help as you wrap up your lab assignment
  • Did anyone notice that next week is spring break?
• Lecture assignment recap
• Exam coming up after break
  • it is a 48 hour, 5 minute take home: Wednesday 3:55 PM through Friday at 4:00 PM
  • take as much time as you wish, but expect to spend no more than about 3 hours
  • you may consult your own notes, the SG&G text, your graded and ungraded labs and lecture assignments, class examples in the shared area, any of my online lecture notes, and the assigned supplemental readings
  • you may write your answers on paper, but I would prefer typeset responses (electronic submission OK, just return signed exam paper later)
  • topics up to the end of class today are fair game
  • old exam: see handout
  • set up a time for some review early in the week after break
• A look at some shell implementation details
• Wrapup: hardware support for process synchronization
  • using atomic swap instruction
• Semaphores
  • abstract synchronization primitive
  • wait/signal semantics
  • using to solve the critical section problem
  • implementation idea
  • POSIX semaphores
  • pthreads mutexes
  • using as a general synchronization tool

Other than the optional lab resubmissions, you're off the hook over the break once your CPU simulator studies are in.