------------------------------------------------------
Lecture 06 - February 14, 2003
------------------------------------------------------
AGENDA:
0 Admin
1 P2 questions?
2 Homework #2
3 Ch 2.3: classical IPC problems
4 Quiz #2

------------------------------------------------------
0 - ADMIN
------------------------------------------------------
Startout Q: Why do O/S people care about the dining
  philosophers?

Today:
* HM #2
* Quiz #2

Checking of system/library calls for possible failure
* soapbox
* P1 grade issues

------------------------------------------------------
1 - P2 QUESTIONS
------------------------------------------------------
Questions?

------------------------------------------------------
2 - HOMEWORK #2
------------------------------------------------------
Review/grade homework

------------------------------------------------------
3 - CH 2.3 - CLASSICAL IPC PROBLEMS
------------------------------------------------------
THE DINING PHILOSOPHERS
* describe scenario
* discuss problem
  - it's a "competing for resources" problem
* why doesn't fig 2-17 (p. 77) work?
* couldn't we do a "down(&mutex)" and "up(&mutex)"
  around the take_fork() through put_fork() calls?
* discuss code for solution fig 2-18 p. 78
- you really have to beat on it yourself until you
  have persuaded yourself that it works. It does.

READERS AND WRITERS
* describe scenario
* discuss problem
  - it's a "mutual exclusion/race conditions" problem
* discuss possible problem w/ fig 2-19 p. 79
* discuss solution

THE SLEEPING BARBER
* Similar to reader-writer problem
* Probably won't have time to cover in class

------------------------------------------------------
4 - QUIZ #2
------------------------------------------------------
As stated.
- 10 minutes


COS 421 - Lecture Notes #6		SPRING 2003	
COS421-lect-2003-02-10.doc	Page 1	Printed 14.02.03