In a real computer system, neither the resources available nor the demands of processes for resources are consistent over long periods (months). Resources break or are replaced, new processes come and go, new resources are bought and added to the system. If deadlock is controlled by the banker's algorithm, which of the following changes can be made safely (without introducing the possibility of deadlock), and under what circumstances?

a. Increase Available (new resources added)

b. Decrease Available (resource permanently removed from system)

c. Increase Max for one process (the process needs or wants more resources than allowed).

d. Decrease Max for one process (the process decides it does not need that many resources)

e. Increase the number of processes f. Decrease the number of processes

Answer & Explanation:

a. Increase Available (new resources added) : This will not cause any issue and changes will executed safely provided its already in the safe state.

b. Decrease Available (resource permanently removed from the system) : The system will assumed there was a certain number of resources available and removing it permanently could lead to issue and deadlock.

c. Increase Max for one process (the process needs more resources

than allowed, it may want more) : This could have an effect on

the system and introduce the possibility of deadlock.

d. Decrease Max for one process (the process decides it does not need

that many resources) : This could safely be changed without any

issue or deadlock.

e. Increase the number of processes: This could be allowed assuming

that resources were allocated to the new processes such that the system does not leave it safe state.

f. Decrease the number of processes: This could safely be changed without any issue.