Four main tasks of OS

• Process Management

        Process creation
        Process execution control
        Interaction of the process with signal events
        Process monitoring
        CPU allocation
        Process termination

• Interprocess Communication

        Synchronization and coordination
        Deadlock and Livelock detection
        Process Protection
        Data Exchange Mechanisms

• Memory Management

        Services for file creation, deletion, reposition and protection

• Input/Output Management

        Handles requests and release subroutines for a variety of peripherals and read, write and reposition 
        programs