Week 9

Assignment: Dining Java Philosophers

Assign 4, due Wed, Apr 3, 11:59pm
- or do you need an extension?
- questions?

Monitors

Ben-Ari slides: PDF
- slide 7.6 (p. 165)
My monitor notes: PDF

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!)

Channels

CSP and Go!
Hoare's 1978 CSP paper: https://spinroot.com/courses/summer/Papers/hoare_1978.pdf
- Go implementation of examples from paper: https://godoc.org/github.com/thomas11/csp
Rob Pike's Google I/O 2012 - Go Concurrency Patterns: https://youtu.be/f6kdp27TYZs
Peter Welch's slides introducing CSP and occam-pi (but we will use Go this semester!)
- Occam-pi Lecture Notes
- Next time: Objects Considered Harmful (slide 27 of motivation.pdf slides)
Demo and codewalk of csp-dining-philosophers.go
- Go language features highlighted:
  - channels
  - select
- Design basis for solution in Go: go routines (processes)
  - room (communicates with philosophers over channels)
    - for philosophers to enter/leave – at most 4 at a time to prevent deadlocking, 5th philosopher blocks
  - forks (communicate with philosophers over channels)
  - philosophers (communicate with forks over channels)