Non-Preemptive and Preemptive Threads

Goal

• Understand different kinds ofl threads as well as the concept of critical section.

Reading Assignments

• MOS 2.2.3-2.3.3
• If you are interested in more reading, see Introduction to Programming with Threads (pages 1-7).

Discussion Topics

• What are the differences between a kernel thread and a user-level thread?
• Suppose two students share a house and they share the responsibility of buying milk, but their fridge is small.  So, they would like to avoid buying too much milk.  One day, 
 

Time	Student A	Student B
3:00	Look in fridge and out of milk
3:05	Leave for Wawa
3:10	Arrive at Wawa	Look in fridge and out of milk
3:15	Buy milk	Leave for Wawa
3:20	Arrive home and put milk away	Arrive at Wawa
3:25		Buy milk
3:30		Arrive home and put milk away Oh no!

 
At each step, the student can be distracted to do other things.   How would you solve this problem?