EXAM 2 SOLUTION

 

 

 

1-     A semaphore is a variable type used in mutual exclusion or resource management method where tasks sleep waiting for that variable to be granted

P112 of the textbook shows an example of semaphores used to solve the producer-consumer problem

 

2-     A mutex is a variable that can be in one of the two states: lock or unlocked. That variable type is also used for mutual exclusion

P113 shows an implementation of a mutex in those two states

 

3-     The different techniques available for scheduling in batch systems are:

a)      FIRST-COME FIRST SERVED

b)      SHORTEST JOB FIRST

c)      THREE LEVEL SCHEDULING

 

4-     A real time system: is a system where time plays an important role. We have two categories: the Hard Real time (where an absolute deadline has to be met) and a Soft Real Time.

5-      Thread Scheduling:  show local scheduling (user space) and global scheduling (kernel space)

6-     dispatch latency : amount of time between stopping one process and starting the next one

7-     question 7 to 9 will be explained in class