1. Are there any situations with the MESI cache coherence protocol in which a cache line is present in the local cache but for which a bus transaction is nevertheless needed? If so, explain.
2. Suppose that there are n CPUs on a common bus. The probability that any CPU tries to use the bus in a given cycle is p. What is the chance that
a. The bus is idle (0 requests).
b. Exactly one request is made.
c. More than one request is made.