A system/method of enhanced backplane messaging among a plurality of
computer boards communicating over a common bus uses a set of
pre-allocated buffers on each computer board to receive messages from
other computer boards. Each sending computer board is represented on each
remote computer board by a descriptor ring with pointers to pre-allocated
buffers on that remote computer board. When a sending computer board has a
message to deliver to a remote computer board, the sending computer board
uses its DMA controller to transfer the message into the pre-allocated
buffers on the remote computer board. The sending computer board also
sends a mailbox interrupt to the remote computer board. The remote
computer board interrupt handler searches its descriptor rings and
manipulates a series of pointers to move messages from the descriptor
rings to the intended receiving application(s). Pointer manipulation is
also used to replenish the descriptor ring(s) with empty buffer(s).
