איך עובד ReaderWriter? (אנימציה פשוטה)

Welcome to understanding Reader-Writer synchronization, a fundamental concept in concurrent programming.At the heart of this mechanism is a shared resource that multiple processes need to access.The Reader-Writer mechanism uses three main components to manage access.First, we have a counter that keeps track of how many readers are currently accessing the resource.Two semaphores control access: one for readers and one for writers.Multiple reader processes can access the resource simultaneously when there's no active writer.Let's examine the basic rules of Reader-Writer synchronization.The resource can be in one of three states: idle, being read, or being written to.When a reader wants to access the shared resource, it first checks if there are any active writers.If no writer is active, the reader increments the reader counter and gains access.Multiple readers can access the resource simultaneously, as long as there's no active writer.When a reader finishes, it decrements the counter and exits the resource.Other readers can continue accessing the resource independently.When the last reader exits, the resource becomes available for writers.When a writer process wants to access the shared resource, it must wait for all active readers to finish.Here comes a writer process requesting access to the resource.The writer must wait until all readers complete their operations.Once all readers have finished, the writer gets exclusive access to the resource.To prevent writer starvation, new readers are blocked from entering while a writer is waiting.After the writer completes its operation, it releases the resource.Once the writer is finished, the waiting readers can access the resource.