A system and 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 moves
the messages from the descriptor rings to the receiving application(s) via pointer
manipulation. Chained DMA transfers are used to eliminate any data transfers by
the processor itself across the bus.