GATE CS Mastery
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GATE CS 2012 · Operating Systems

Question 8

MCQPrinted as CS Q.81 markWrong answer: −1/3Easy (estimate)

Question

A process executes the code

fork();
fork();
fork();

The total number of child processes created is

Choose one option
Official answer and solution
Official answer
C
From
Official GATE 2012 answer key

Solution

Determine the total number of processes created by n successive fork calls and subtract the initial parent process.

Each call to fork() duplicates all existing processes:

  • Initially, there is 1 parent process.
  • After the first fork(), the number of processes doubles to 21=22^1 = 2.
  • After the second fork(), the number of processes doubles to 22=42^2 = 4.
  • After the third fork(), the number of processes doubles to 23=82^3 = 8.

Among these 8 total processes, 1 is the original parent process, and the remaining are newly created child processes:

Total child processes=23−1=8−1=7\text{Total child processes} = 2^3 - 1 = 8 - 1 = 7

Thus, 7 child processes are created, which matches option (C).

Final answer

C

The answer is the one in the official GATE answer key. The solution is this site's own explanation.

Source

Paper
GATE 2012 Computer Science and Information Technology (CS)
Question
8 of 65, printed as CS Q.8
Section
Computer Science and Information Technology

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