Abstract: A scheduling method and apparatus for use by a processor that controls storage devices of a data storage system is presented. The method allocates processing time between I/O operations and background operations for predetermined time slots based on an indicator of processor workload.

Abstract: Systems and methods are provided for executing a vendor specific command in a storage area network including a plurality of data storage volumes and at least one host. In one embodiment, a system includes an intelligent multi-protocol switch (IMPS) and a storage and switch controller that is coupled to the IMPS. The IMPS receives a command from the at least one host. The command includes a command byte field storing a vendor specific service action. The storage and switch controller receives the command from the IMPS. A processor included in the storage and switch controller interprets the vendor specific service action and executes the command.

Abstract: A scheduling method and apparatus for use by a processor that controls storage devices of a data storage system is presented. The method allocates processing time between I/O operations and background operations for predetermined time slots based on an indicator of processor workload.

Abstract: An expandable memory system and a method for operating a memory system having a variable number of memory banks are described. The memory system can utilize a variable number of separately replaceable memory banks which can be implemented with memory element, such as dynamic random access memory chips, which are of differing speeds and or sizes. The memory system implements an interleaving of memory addresses among the memory banks as a function of the number of banks actually present so that successive memory accesses are not unnecessarily delayed by the recovery times of the memory elements. The memory system includes a programmable address decoder having a writable memory which provides bank address signals. Each of the banks includes a respective delay line for providing an output signal a respective presettable time after address signals are received by that bank for signalling to the host that data is ready to be transferred.