Instructions: these are modified versus prior instructions

Responses due by 1:00 PM Thursday
Send the the course staff email, using the staff email alias (available on the home page)
Requirement: include your response in the email itself, not as an attachment. Use plain text.
Answer the question below.
Pose an additional question about the paper that articulates what you found most confusing, least specified, etc.

Question. See Figure 6. Why does the cache coherence protocol generate a Broadcast message when the state of a cache line transitions from 'S' to 'M'? In other words, why can't the cache coherence protocol use a Direct Probe (DP) or Direct Invalidate (DI) message in this case?