Outline four essential approaches used when implementing mutual exclusion to manage shared resources. (4 marks)DICT MOD 1 July 2020

Mutual exclusion is a technique used to manage shared resources in a computer system, in order to ensure that only one process or thread can access the resource at a time. There are several approaches that can be used when implementing mutual exclusion, and each approach has its own advantages and disadvantages. Here are four essential approaches:

1. Lock-based synchronization: Lock-based synchronization involves the use of locks (such as semaphores or mutexes) to control access to shared resources. A process must acquire a lock before it can access the resource, and it must release the lock when it is finished using the resource. This approach is simple to implement, but it can suffer from performance issues if the locks are not used efficiently.
2. Token-based synchronization: Token-based synchronization involves the use of a special token (such as a “turnstile”) to control access to shared resources. A process must acquire the token before it can access the resource, and it must release the token when it is finished using the resource. This approach can be more efficient than lock-based synchronization, but it requires more complex mechanisms to ensure the fairness of access to the resource.
3. Message passing: Message passing involves the use of messages (such as requests and responses) to coordinate access to shared resources. A process can send a request for access to the resource to another process or to a special manager process, and it can receive a response indicating whether the request has been granted or denied. This approach can be more flexible than other approaches, but it requires more overhead to manage the communication of messages.
4. Hardware support: Some hardware platforms provide support for mutual exclusion, such as special instructions or registers that can be used to control access to shared resources. This approach can be very efficient, but it is platform-specific and may not be available on all systems.