Week 4
Lecture Notes
Critical Sections
Recap from last week:
UPC setup, including ssh keys and script to compile/run
Finish up demo of last two versions of UPC temperature programs
vim questions? tips/advice?
Programming assignment 2 due: next Tue, Feb 17
Ben-Ari Ch 3
slides:
PDF
begin slide 3.1, p. 50
The approaches to enter and exit critical sections were low-level and brittle
low-level because: relied on busy-waiting and checking on global variables
brittle because: many reasons!
processes relied on each other to enter their own CS!
hard-coded for a specific number of processes (i.e., 2)! what about for n?
Class Exercise
More practice with interleavings
(Adapted from Problem 2.19 from Andrews's MPD text)
mpd-2.19-interleavings.pdf
(handout)
Semaphores
Next we introduce the abstraction of semaphores to control access to CS
Ben-Ari Ch 6
slides:
PDF
begin slide 6.1, p. 111
Homework
Written HW: Ben-Ari p. 39:
Exercises 2, 3, and 4
Haven't forgotten that I owe you feedback–sorry!
Programming Assignment 2
UPC Exercises 1.1 through 1.7
Due: Tue, Feb 17, 11:59pm
Here's a link:
private