When write happens, object has a version number incremented
To read, collect votes from replica managers with version numbers of object. Guaranteed to have at least one up to date copy if in read quorum, from which read occurs.
To write, collect votes from replica managers with version numbers of object. If write quorum with up to date copy not discovered, then copy up to date copy around to create write quorum. Then write is allowed.
Manipulating R and W give different characteristics eg R = 1 and W = number of copies gives unaminous update.
Cached copies of objects can be incorporated as weak representatives with 0 votes, but usable for reads.