Monitors in Operating System

In an operating system, a Monitor is a high-level synchronization mechanism used to ensure coordination and mutual exclusion between processes. A monitor is a programming construct that controls resources and processes at the programming language level. Its purpose is to allow only one process at a time to access shared resources, thereby avoiding problems like data inconsistency and race conditions.

A monitor is designed to manage resources and processes in a structured way. It enforces mutual exclusion, meaning only one process can execute code within the monitor at a time. A monitor acts like an object, containing shared data and the procedures that operate on it, and provides a locking system to ensure coordination.

A monitor consists of three main elements:

A monitor's primary job is to enforce mutual exclusion and simplify synchronization. Only one process can be active inside the monitor at any time. When a process enters, it acquires a lock, and when it exits, the lock is released. Condition variables (`wait()` and `signal()`) are used to manage process states when they need to wait for a specific condition to be true.

Monitors can be categorized based on their implementation: Structured Monitor, Non-Structured Monitor, Condition Monitor, and Object Monitor (used in object-oriented languages like Java).