Why is disabling interrupts a pessimistic approach to ensure concurrency control?
Disabling interrupts before entering a critical region ensures that no interrupt service routines can intervene. It also ensures that clock interrupts will be disabled which means that the CPU cannot be switched to another process. Thus the process need have no fear of any other process interfering with its critical region. Thus, disabling interrupts is a brute-force approach to avoid concurrency-related problems.This approach is pessimistic because it assumes that every interrupt will give control to a process which will want to interfere with the earlier process’ critical region. In reality this is not the case.
