Each process P_i,i=1.....9 is coded as follows

  Repeat
  P(mutex){
  critical section
  }
  V(mutex)
  Forever

The code for P₁₀ is identical except that it uses V(mutex) in place of P(mutex). What is the largest number of processes that can be inside the critical section at any moment?

The concurrent programming constructs fork and join are as below: Fork (label) which creates a new process executing from the specified label join (variable) which decrements the specified synchronization variable (by 1) and terminates the process if the new value is not 0. Show the precedence graph for S1, S2, S3, S4 and S5 of the concurrent program below.
N = 2
M = 2
fork L3
fork L4
S1
L1 : join N
S3
L2: join M
S5
L3:S2
goto L1
L4:S4
goto L2
next:

A solution to the Dining Philosophers Problem which avoids deadlock is

At a particular time of computation the value of a counting semaphore is 7. Then 20 P operations and 15 V operations were completed on this semaphore. The resulting value of the semaphore is: