Methods are provided for detecting the processing status of data blocks. A
hash value is used at times in place of a block's data content, thereby
reducing processing of the block. Superblocks and superblock hash values
are used to manage collisions between hash values of individual blocks,
in order to reduce or eliminate the risk that blocks having different
content will be treated as though they have the same content merely
because they have the same hash value. Systems and configured storage
media are also provided.