courses:cs377-202651:week7

Monitors

Marc's Lecture Notes: PDF
Ben-Ari Ch 7
- begin slide 146
Dr. Seuss on Deadlock:
- The Zax
Semaphores vs. Monitors

Semaphore	Monitor
`wait` may or may not block	`waitC` always blocks
`signal` always has an effect	`signalC` has no effect if queue is empty
`signal` unblocks an arbitrary blocked process	`signalC` unblocks the process at the head of the queue
a process unblocked by signal can resume execution immediately	a process unblocked by signalC must wait for the signaling process to leave monitor

Class participation with monitors:

The One-Lane Bridge problem:

Cars coming from the north and south arrive at a 
one-lane bridge. Cars heading in the same direction 
can cross the bridge at the same time, but cars 
heading in opposite directions cannot.

can we find a way to be safe, fair, and efficient?
PDF (with thanks to Charlie Hughes!)

Java case study (starter code for Assign 4)
- starter code for Assign 4 (for after the break)
- this version deadlocks!
- you will use two different approaches to fix:
  - synchronized methods
  - synchronized code blocks

Dining UPC Philosophers PDF
- Note: version 3 is required (sorry for any confusion!)
  - it can definitely be implemented with busy waiting
  - the challenge is whether it can be implemented without busy waiting!
Assigned: Thu, Feb 19
Due: Tue, Mar 3, 11:59pm (Tue before Spring break)

Week 7

From Semaphores to Monitors

Monitors in Java

Midterm Programming Assignment