Abstract: A data storage system wherein a host computer is coupled to a bank of disk drives through a system interface. The interface includes a system memory comprising a pair of system memory sections. Each one of the system memory sections has a plurality of addressable locations for storing data written into such one of the memory sections at the addressable locations. A pair of system busses is provided, each one of the pair of system busses being coupled to a corresponding one of the pair of system memory sections. A plurality of directors is coupled to the system memory through the system bus. The directors are configured to control data transfer between the host computer and the bank of disk drives as such data passes through the system memory.