This protected section is the critical section or critical region. It cannot be executed by more than one process at a time. Typically, the critical section accesses a shared resource, such as a data structure, a peripheral device, or a network connection, that would not operate correctly in the context of multiple concurrent accesses. Need for critical sections. Different codes or processes.
Introduction of Process Synchronization - GeeksforGeeks.
Process Synchronization means sharing system resources by processes in a such a way that, Concurrent access to shared data is handled thereby minimizing the chance of inconsistent data. Maintaining data consistency demands mechanisms to ensure synchronized execution of cooperating processes. Process Synchronization was introduced to handle problems that arose while multiple process executions.Progress - If no process is executing in its critical section and there exist some processes that wish to enter their critical section, then the selection of the processes that will enter the critical section next cannot be postponed indefinitely 3. Bounded Waiting - A bound must exist on the number of times that other processes are allowed to enter their critical sections after a process has.Remainder Section Rest of the code AFTER the critical section. PROCESS SYNCHRONIZATION Critical Sections. 6: Process Synchronization 8 The critical section must ENFORCE ALL THREE of the following rules: Mutual Exclusion: No more than one process can execute in its critical section at one time. Progress: If no one is in the critical section and someone wants in, then those processes not in.
I was reading Critical Section Problem from Operating System Concepts by Peter B. Galvin. According to it. 1) Progress is: If no process is executing in its critical section and some processes wish to enter their critical sections, then only those processes that are not executing in their remainder section can participate in deciding which will enter its critical section next, and this.Then turn is set to j to allow the other process to enter their critical section if process j so desires. The while loop is a busy loop ( notice the semicolon at the end ), which makes process i wait as long as process j has the turn and wants to enter the critical section. Process i lowers the flag( i ) in the exit section, allowing process j to continue if it has been waiting. Figure 5.2.
