Please answer the following:

Q1. Briefly explain why interrupt service routines cannot be signalled.

Q2. Briefly explain the difference between a semaphore and a mutex.

Q3. Explain what is meant by a mutually exclusive shared resource.

Q4. Give an example of where a counting semaphore might be used.

Q5. ) A number of algorithms has been developed for avoiding or preventing deadlock and yet many systems don't make use of them. Give one reason why.