Scheduling Quiz
 
1) Which will typically be given a higher priority, a low priority real time task or a high priority non-real-time task?

2) How long does a context switch typically take?
          A few machine instructions
          A few hundred machine instructions
          A few milliseconds
          A few seconds
 
3) Mike says Euclid uses round robin without preemption. He's wrong (he's always wrong). But how can you prove he's wrong. Hint:  You can write some code and run it.


 
 
 
 
4) For the processes below, what process is running at time slice 5 for soonest deadline next with preemption?  
          ProcID  ArrivalTime     Time Needed     Deadline           Priority

          1         2               1                 before 3            1 (highest)
          2         1               10                before 999          3
          3         2               5                 before 9            2
          4         5               4                 before 10           4 (lowest)

 
5) For the processes above, using a strict priority scheduler without preemption, who is running at time 8?
 

 

6) I have a bunch of processes that need 3,2,1,6,5,and 4 timeslices.  What order of the processes would minimize total wait time?

 

 

7) In process scheduling, what is aging?  (10 words or less)

 
 
 
8) What problem does aging solve? (10 words or less)
 
 
 
 
9) (Yes/No) Is starvation possible for priority scheduling with preemption schedulers?

 

 

10) Which would make more sense and be more useful?  If a task uses all of it's time slice
  It is given a higher priority and is more likely to get more CPU
  It is given a lower priority and is more likely to get less CPU

 

11)List an application that is obviously hard real time and soft real time.
 Hard: _______________________________________________
 Soft: _______________________________________________


 

12) Who is the silliest person in the world?

 

13) (spawn/fork+exec) What is likely faster, spawn or fork followed by exec?

 

14) A process gets context switched out of the CPU, and later context switched back on the CPU.  How can it tell this has happened?  (10 word max)