Some distributed transaction processing systems replicate data at two or more sites separated geographically. A common technique for organizing replicated systems is one in which transactions that update a data item must change all replicas. Hence, one possible integrity constraint in a replicated system is that the values of all of the replicas of an item be the same. Explain howtransactions running on such a system might violate

a. Atomicity
b. Consistency
c. Isolation
d. Durability

a. A transaction updates one replica and then crashes before it can update the others,
but the update to the first replica is not rolled back.
b. A transaction updates one replica, but not others, thus violating the integrity
constraint that all replicas have the same value.
c. One transaction updates two different items, each of which is replicated; Another
transaction sees one replica before change, the other after.
d. Two replicas are updated; one site crashes and forgets the update