Abstract: A mechanism prioritizes cross interrogate requests between multiple requestors in a multi-processor system where the delay due to cable length interconnecting requestors results in requests not being received within one machine cycle. Local and remote cross interrogate (XI) requests are latched up in storage control element (SCE) temporary registers before being prioritized. The local request is staged in a local delay register. The local request is selected from the local delay register by synchronization control logic, instead of the temporary register, when the remote request is issued one cycle earlier than the local request, or when both local and remote requests are issued at the same time, but the remote requests is from a master SCE. The staging of the local requests can be extended to multiple cycles, corresponding to the length of the cables between SCEs.

Abstract: This disclosure describes an efficient method of moving data from one location in memory to another without caching the data. This includes data transfers from one main storage location to another, transfers between main and expanded storage, and transfers from one expanded storage location to another.