QUESTION 1

Consider the following processes, their parameters (arrival time, CPU burst duration and priority):

PID | Arrival time | Burst time | Priority

-------------------------------------------------------------------------

1 0 8 4

2 3 6 3

3 6 4 5

4 10 5 2

What is the average waiting time for SRTF scheduler ?

QUESTION 2

What events necessitate critical sections to avoid race conditions inside a preemptive kernel ? ( CHOOSE ALL THAT APPLY)

interrupts

some system calls

all library calls

QUESTION 3

A system with virtual memory has 3 frames of physical RAM. What is the content of the three frames (in order from frame 0 to frame 2) after the

1, 0, 2, 3, 0, 4, 3, 2, 3, 4, 4, 1, 2, 3

string of references is executed, using the Optimal page replacement algorithm ?

A. 1, 2, 3

B. 3, 1, 2

C. 2, 1, 3

D. 3, 2, 1

a system call to create a new process