Reference no: EM132331152

Suppose the following two processes, foo and bar, are executed concurrently and share the semaphore variables S and R (each initialized to 1, or in other words initially unlocked). Also the integer variable x is initialized to 0:

void foo()

{   do

   {

       semWait(S);

       semWait(R);

       x++;

       semSignal(S);

       semSignal(R);

   } while (true);

}

void bar()

{   do

   {

       semWait(R);

       semWait(S);

       x--;

       semSignal(S);

       semSignal(R);

   } while (true);

}

a. If the two processes get about equal cpu time, what would you expect the final value of x to be? For example, if you know for a fact that foo() and bar() both ran exactly 100 times, what value should x have? Is it possible for it to be something other than 0 if foo() and bar() both run an equal number of times?