Process Synchronization Two process Solution (Algo-2) Deadlock Concept, Flag concept.
Process Synchronization Two process Solution (Algo-2) Deadlock Concept , Flag concept.
Contents [hide]
- 1 Process Synchronization – Two Process Solution (Algo-2) | Deadlock & Flag Concept
- 2 Introduction to Process Synchronization
- 3 Two-Process Solution (Algorithm-2)
- 4 Algorithm-2 (Flag Concept Based Approach)
- 5 Assumptions:
- 6 Algorithm (Using Flags)
- 7 Explanation:
- 8 Deadlock Concept
- 9 Can Deadlock Occur in This Algorithm?
- 10 Avoiding Deadlock: Peterson’s Solution
- 11 Why is Peterson’s Solution Deadlock-Free?
- 12 Conclusion
- 13 Process Synchronization Two process Solution (Algo-2) Deadlock Concept, Flag concept.
- 14 Chapter 6: Synchronization
Process Synchronization – Two Process Solution (Algo-2) | Deadlock & Flag Concept
Introduction to Process Synchronization
Process Synchronization is a mechanism to ensure that multiple processes can execute in a way that avoids inconsistencies and conflicts when accessing shared resources. One of the key challenges in synchronization is deadlock.
Two-Process Solution (Algorithm-2)
The Two-Process Solution for synchronization ensures mutual exclusion, progress, and bounded waiting. It typically uses flags and turn variables.
Algorithm-2 (Flag Concept Based Approach)
This method relies on two flags to indicate whether a process wants to enter the critical section.
Assumptions:
- There are two processes, P1 and P2.
- Each process sets its flag to indicate entry to the critical section.
- The process checks the other process’s flag before entering.
Algorithm (Using Flags)
Explanation:
- Each process sets its flag (
flag[i] = true
) before entering the Critical Section (CS). - It checks whether the other process’s flag is true. If yes, it waits.
- If the other process is not in the CS (
flag[j] = false
), it enters the CS. - After execution, the process resets its flag (
flag[i] = false
) and enters the Remainder Section.
Deadlock Concept
A deadlock occurs when two or more processes wait indefinitely for resources held by each other.
Can Deadlock Occur in This Algorithm?
Yes! This algorithm can lead to deadlock in the following situation:
- Both P1 and P2 set their flags at the same time (
flag[0] = true
,flag[1] = true
). - Both enter their respective while loops (
while (flag[1]);
andwhile (flag[0]);
). - Now, both are waiting for each other to release the flag, leading to a deadlock.
Avoiding Deadlock: Peterson’s Solution
Peterson’s Algorithm improves the Two-Process Solution by introducing a turn variable along with flags.
Why is Peterson’s Solution Deadlock-Free?
- If both processes want to enter, the turn variable ensures only one gets priority.
- This prevents both from waiting indefinitely on each other.
Conclusion
- Algorithm-2 (Flag Concept) can cause deadlock if both processes set their flags simultaneously.
- Peterson’s Algorithm eliminates deadlock using a turn variable.
- Process Synchronization is essential in operating systems, multi-threading, and concurrent computing.
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