A process executes the following code

for (i = 0; i < n; i + +) fork ( ); 

The total number of child processes created is

Which of the following is/are true of the auto-increment addressing mode?
$${\rm I}.\,\,\,$$ It is useful in creating self-relocating code
$${\rm II}.\,\,\,$$ If it is included in an Instruction Set Architecture, then an additional $$ALU$$ is required for effective address calculation.
$${\rm III}.\,\,\,$$ The amount of increment depends on the size of the data item accessed

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?