Abstract: The present invention discloses technology that extends single-ported storage devices by providing multiple access paths and power control in data storage subsystems. In an embodiment, the system provides circuitry associated with single ported storage devices to connect the data and control signals of the storage devices to two redundant storage controllers and to control the storage device power.

Abstract: The present invention relates to systems and methods for providing multiple access paths to a single ported storage device used in data storage subsystems. In an embodiment, the system provides circuitry associated with single ported storage devices, including a coupling circuit for signals which include the data and control paths to and from redundant storage device controllers. In this embodiment, the additional control in the form of discrete signal lines or through additional commands is used to manage routing of the signals to and from a redundant data storage controller. Further, each redundant data storage controller preferably has its' own primary set of storage devices. If one of the controllers fails, the redundant controller can switch its' control to the failed controller's storage devices thus maintaining user access to the data contained on those storage devices.