An operating system uses Shortest Remaining Time first $$(SRT)$$ process scheduling algorithm. Consider the arrival times and execution times for the following processes:

What is the total waiting time for process $$P2?$$

Consider three processes, all arriving at time zero, with total execution time of $$10,20,$$ and $$30$$ units, respectively. Each process spends the first $$20$$% of execution time doing $${\rm I}/O$$, the next $$70$$% of time doing computation, and the last $$10$$% of time doing $${\rm I}/O$$ again. The operating system uses a shortest remaining compute time first scheduling algorithm and scheduling a new process either when the running processes gets blocked on $${\rm I}/O$$ or when the running process finishes its compute burst. Assume that all $${\rm I}/O$$ operations can be overlapped as much as possible. For what percentage of time does the $$CPU$$ remain idle?

Consider three processes (process id $$0,1,2,$$ respectively) with compute time bursts $$2, 4,$$ and $$8$$ time units. All processes arrive at time zero. Consider the longest remaining time first $$(LRTF)$$ scheduling algorithm. In $$LRTF$$ ties are broken by giving priority to the process with the lowest process id. The average turn around time is

Consider the following code fragment:

if (fork() == 0)
{
   a = a + 5;
   printf("%d, %d \n", a, &a);
}
else
{
   a = a - 5;
   printf ("%d, %d \n", a, &a);
}

Let $$u,v$$ be the values printed by the parent process, and $$x,y$$ be the values printed by the child process. Which one of the following is TRUE?