Chapter 2

Question 1

What is a thread

Answer 1

a sequence of events

Question 2

what is a interval? A0 = (a0,a1)?

Answer 2

Time between a0 and a1

Question 3

Notation for precedence

Answer 3

A0->B0

Question 4

What is a critical section?

Answer 4

block of code that can only be executed by 1 thread at a time

Question 5

Properties of a good Lock algorithm?

Answer 5

Mutual Exclusion, Deadlock-free, Starvation-free

Question 6

What does deadlock-free mean?

Answer 6

If threads attempt to acquire the lock, at least 1 will succeed

Question 7

What does Starvation-free mean

Answer 7

every thread that attempts to acquire the lock will eventually succeed

Question 8

Basic idea of LockOne

Answer 8

set flag, check to see if other is in CS, (if yes wait, if no enter CS)

Question 9

Problem with LockOne

Answer 9

Can lead to deadlock

Question 10

Basic idea of LockTwo

Answer 10

Set self as victim, while current thread is victim wait until other thread becomes victim

Question 11

Problem with LockTwo

Answer 11

If only 1 thread runs it will stay victim forever -> never runs

Question 12

Peterson lock basic idea

Answer 12

Combine lock 1 and 2

Question 13

how many waiting rooms are there in a Filter Lock

Answer 13

n-1

Question 14

In the filter lock, is the CS closer to the top (higher level) or bottom

Answer 14

Top

Question 15

Is the Filter Lock fair?

Answer 15

No. Threads can be overtaken

Question 16

Idea of Bakery Algorithm

Answer 16

Give threads a label, Let lower labels run 1st

Question 17

Problem using labels + solution for Bakery

Answer 17

If normal labels: infinite numbers needed. Solution: Sequential Timestamps