In cancelling the cast out portion of a combined operation including a data
access related to the cast out, the combined response logic explicitly
directs a horizontal storage device at the same level as the storage
device initiating the combined operation to allocate and store either the
cast out or target data. A horizontal storage device having available
space--i.e., an invalid or modified data element in a congruence class for
the victim--stores either the target or the cast out data for subsequent
access by an intervention. Cancellation of the cast out thus defers any
latency associated with writing the cast out victim to system memory while
maximizing utilization of available storage with acceptable tradeoffs in
data access latency.