GATE CS 2008 Q66 — System Calls

To find the total number of child processes created, let us track the total number of active processes after each iteration of the loop.

Initially, before the loop begins, there is only $1$ process (the original parent process).

• Iteration 1 ($i = 0$): The $1$ existing process calls fork(), doubling the number of processes to $2^1 = 2$.
• Iteration 2 ($i = 1$): Both of these $2$ processes call fork(), doubling the total to $2^2 = 4$.
• Iteration $k$: Each of the $2^{k-1}$ processes calls fork(), resulting in $2^k$ processes.

After the loop finishes executing all $n$ iterations, the total number of processes running is:

Since the execution started with $1$ original parent process, the number of newly created child processes is:

Thus, the correct option is B.