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!)
- 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)