(19) United States
(12) Patent Application Publication (io) Pub. No.: US 2004/0177126 Al
Maine (43) Pub. Date: Sep. 9,2004
(54) BROADCAST BRIDGE APPARATUS FOR
TRANSFERRING DATA TO REDUNDANT
MEMORY SUBSYSTEMS IN A STORAGE
(75) Inventor: Gene Maine, Longmont, CO (US)
HUFFMAN LAW GROUP, PC.
1832 N. CASCADE AVE.
COLORADO SPRINGS, CO 80907-7449 (US)
(73) Assignee: Chaparral Network Storage, Inc.,
Longmont, CO (US)
(21) Appl. No.: 10/368,688
(22) Filed: Feb. 18, 2003
Publication Classification (51) Int. CI.7 G06F 15/16; G06F 13/36
A bus bridge apparatus for performing broadcasted writes to redundant memory subsystems in a network storage controller is disclosed. The bus bridge includes a PCI-X target that receives a write command on a first PCI-X bus on one side of the bridge. The target is coupled to two PCI-X masters coupled to primary and secondary memory subsystems by respective PCI-X buses on the other side of the bridge. A first FIFO buffers the write command data between the target and the first master, and a second FIFO buffers a copy of the data between the target and the second master. The first and second masters concurrently retransmit the write command on their respective PCI-X buses to the primary and secondary memory subsystems. However, the second master only retransmits if broadcasting is enabled and the write command address is in a broadcast address range known by the bus bridge.