GATE CS 2016 Set 2 — Question 58

MCQ+2 / -0.67MediumRace Conditions & Critical SectionProcess SynchronizationOperating System

Operating System → Process Synchronization → Race Conditions & Critical Section

Last updated 5 September 2026

Question

Consider the following two-process synchronization solution. Process 0 --------- Entry: loop while (turn == 1); (critical section) Exit: turn = 1; Process 1 ---------- Entry: loop while (turn == 0); (critical section) Exit: turn = 0; The shared variable turn is initialized to zero. Which one of the following is TRUE ?

Correct answer (C) This solution violates progress requirement. Solution This is the Strict Alternation approach. Mutual Exclusion: Satisfied. Only one process can enter the critical section depending on the value of turn . Progress: Violated. If Process 0 is not interested in entering the critical section (or crashes outside the CS), turn remains 0. Process 1 cannot enter even if the CS is free, because it waits for turn == 1 . Thus, a process outside the critical section blocks another process from entering. Bounded Waiting: Satisfied. There is a strict bound (alternation) on waiting. Turn this into a strength. Explore AI-powered practice and doubt support with Success Tracker.

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Correct answer (C) This solution violates progress requirement. Solution This is the Strict Alternation approach. Mutual Exclusion: Satisfied. Only one process can enter the critical section depending on the value of turn . Progress: Violated. If Process 0 is not interested in entering the critical section (or crashes outside the CS), turn remains 0. Process 1 cannot enter even if the CS is free, because it waits for turn == 1 . Thus, a process outside the critical section blocks another process from entering. Bounded Waiting: Satisfied. There is a strict bound (alternation) on waiting.

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