Asynchronous cross memory communication is a fancy way to describe scheduling an SRB. An SRB is a service request block that a task can schedule to request that some service take place in the same address space or another address space. Any data that the requesting task and the service share must be placed in common storage.

SRBs are one way to overlap processing. A task schedules an SRB to perform a service, then continues with its work. When the service completes, it informs the task. The timing, however, is asynchronous; the point when the SRB completes cannot be predicted.