Method and apparatus for extending commands in a cached disk array

DETAILED DESCRIPTION In accordance with the present invention, a storage system is provided which includes a storage controller coupled to a bus and further coupled to a storage device.
The storage controller responsive to requests for accessing data stored on said storage device.
In addition, the storage system includes a memory and a host controller coupled to the bus.
The host controller includes a request queue which is used to store requests received from a host computer for access to data stored on the storage device.
The controller may receive many different requests from many different processes running on the host computer.
The processes may have associated therewith sections of storage space on the storage device.
The requests for data may thus cause an access to physically disparate locations on the storage device.
To prevent an inordinate amount of seeking, the controller examines the queue and bundles requests to physically local locations into a single request.
The bundled requests are then transmitted to the storage controller as a single request.
With such an arrangement, increased storage system performance is achieved since the amount of seeking by the storage device is minimized.
Additionally, the overhead associated with transmitting multiple command to the storage controller is reduced to the overhead associated with transmitting a single command to the storage controller.