Compaq Computer Corporation, Inc.

John E Dimitroff

David L Grant

Robert S Gready

Eugene E Freeman

Raymond A Ritter

Zuohui Zhang

A cascaded removable media data storage system includes a first level enhanced removable media data storage system controller connected to a host or server computer network. Connected in parallel to the enhanced first level removable media data storage system controller are at least two enhanced second level removable media data storage system controllers. Each enhanced second level removable media data storage system controllers is connected to a mirrored group of removable media data storage units.

Cascaded removable media data storage system

A computer system and method using a standardized shareability scheme for establishing a shared level for each of a plurality of storage units located in the computer system. The computer system includes a plurality of hosts and controllers coupled to a peer network (storage area network). Each storage unit is coupled to one of the controllers and includes at least one parametric from a group of parametrics used in classifying the shared level of a particular storage unit. The hosts using the standardized shared levels are able to identify a shareability characteristic of each storage unit.

Computer system and method for establishing a standardized shared level for each storage unit

A network provides a method of virtualizing SCSI semantics onto a non-SCSI transport medium. The network includes a plurality of hosts or initiators, a SCSI bus coupled to a plurality of SCSI devices, and a bridge having a non-SCSI front end coupled to the non-SCSI transport medium and a SCSI back end coupled to the SCSI bus. The bridge provides firmware for performing various techniques for virtualizing certain SCSI semantics to ensure support (proper operation) of the plurality of SCSI devices. Examples of SCSI semantics for virtualizing SCSI-2 semantics onto a Fibre Channel interconnect medium (a non-SCSI-2 transport medium) include reserve/release support, unit attention support, the non-tagged command processing support for the initiators. Reserve/release support is virtualized by implementing virtual command responses to the RESERVE and RELEASE SCSI-2 command using a table for storing Fibre Channel world wide names (WWN) and the arbitrated loop address (ALPA) for the plurality of initiators. Virtual unit attention support is achieved by maintaining alist of initiators and status flags to determine when a unit attention condition needs to be sent to a particular initiator. When a combination of tagged and untagged commands is detected which would violate the rules for mixing such commands on the back-end SCSI bus, any command(s) that would result in the rule violation will be held within the bridge until the currently outstanding conflicting commands have completed.

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Houston, TX, United States of America

John E Dimitroff