A shared variable A , initialized to 0, is operated on by 4 processes w,x,y,z. Processes w and x increment A by 1 while processes y and z decrement it by 2. Each process before reading performs a wait on a semaphore S and signal on S after store or writing.

Ex: Process W () {

wait(S);

Read A to a local var;

increment local var by 1;

Store value from local var to A.

signal(S);

}

Same code for process x. For y,z, the increment is changed to decrement by 2.

i. Find what would be the MAX value of A after all the 4 processes complete execution Fully, if Semaphore S were to be initialized with 1. Explain your answer with the ordering of the processes.

ii. What would be the MAX value of A after all 4 processes complete fully, if Semaphore S were to be initialized with value 2. Explain your answer with the ordering of the processes.