mutual exclusion - TarisMajor/5143-OpSystems GitHub Wiki

Mutual Exclusion is a fundamental concept in concurrent programming and operating system design, ensuring that when one process or thread is executing a critical section of code, no other process or thread can enter that critical section. This prevents race conditions and ensures data integrity when multiple processes or threads access shared resources.

1. Exclusive Access: Only one process or thread can execute within the critical section at any given time, ensuring exclusive access to shared resources.
2. Synchronization Mechanisms: Mechanisms such as locks, semaphores, and monitors are used to implement mutual exclusion, preventing concurrent access to the critical section.
3. Atomic Operations: The operations within a critical section are performed atomically, meaning they are completed without interruption, ensuring consistent access to shared resources.

1. Data Integrity: Ensures that shared resources are accessed and modified in a consistent and controlled manner, preventing data corruption and inconsistencies.
2. Concurrency Control: Essential for managing concurrent execution of processes and threads, ensuring that they do not interfere with each other.
3. System Stability: Proper use of mutual exclusion contributes to the overall stability and reliability of the system by preventing race conditions and deadlocks.

1. Mutex (Mutual Exclusion Object): A mutex is a synchronization primitive that ensures mutual exclusion by allowing only one process or thread to acquire the lock and enter the critical section at a time. Other processes or threads must wait until the lock is released.
2. Semaphore: A semaphore is a synchronization primitive that can control access to a resource by multiple processes or threads. A binary semaphore (also known as a mutex) can provide mutual exclusion, while a counting semaphore can manage multiple simultaneous accesses.
3. Monitor: A monitor is a high-level synchronization construct that combines mutual exclusion and condition variables. It allows processes or threads to wait for certain conditions to be met before entering the critical section.

1. Mutual Exclusion: At least one resource must be held in a non-shareable mode, ensuring that only one process or thread can access the critical section at a time.
2. Progress: If no process or thread is in its critical section, and there are processes or threads that wish to enter, one of them should be allowed to enter without unnecessary delay.
3. Bounded Waiting: There must be a limit on the number of times other processes or threads can enter their critical sections after a process has made a request to enter its critical section and before the requesting process is granted access.

1. Peterson's Algorithm: A classical solution for two-process synchronization that uses two shared variables to ensure mutual exclusion and progress.
2. Test-and-Set Lock (TSL): A hardware-based solution that uses an atomic test-and-set instruction to implement mutual exclusion.
3. Lamport's Bakery Algorithm: A general solution for multiple processes that uses a numbering scheme to ensure that each process is granted access to the critical section in the order of their request.

• Operating System Concepts by Abraham Silberschatz, Peter B. Galvin, and Greg Gagne
• Mutual Exclusion - GeeksforGeeks
• Modern Operating Systems by Andrew S. Tanenbaum
• Wikipedia - Mutual Exclusion
• ChatGPT