"(A)Responses need not occur in the same order as requests - (B)But request order establishes the total order for the system"
Under A, in what way is B guaranteed?
narainsk
Suppose P1 requests X and then P2 requests Y. If X!=Y, we can send P2 a response before sending P1 a response. This is possible because the request order does not impose any restrictions on the response order.
Suppose P1 writes X and then P2 requests X. We need to handle P1's write before P2's read. This is because the request order imposes restrictions on the response order.
"(A)Responses need not occur in the same order as requests - (B)But request order establishes the total order for the system"
Under A, in what way is B guaranteed?
Suppose P1 requests X and then P2 requests Y. If X!=Y, we can send P2 a response before sending P1 a response. This is possible because the request order does not impose any restrictions on the response order.
Suppose P1 writes X and then P2 requests X. We need to handle P1's write before P2's read. This is because the request order imposes restrictions on the response order.
Thus, we can guarantee B in spite of A.