Abstract: Methods and structure for masking of logical unit numbers (LUNs) within a switching device coupled with one or more storage enclosures. Each storage enclosure defines one or more logical volumes each identified by a LUN within the storage enclosures. The switching device gathers LUN definition information regarding each LUN defined by each storage enclosure coupled with the switching device. LUN access permission information may be provided by an administrative node/user defining a level of access permitted or denied for each host system for each LUN for each storage enclosure. The switching device then intercepts a REPORT LUNS command from any host directed to a storage enclosure and responds with only those LUNs to which the requesting host system has permitted access. Further, any other SCSI command intercepted at the switching device directed to a LUN to which the host system does not have access is modified to identify an invalid LUN.

Abstract: In one embodiment of the disclosure, a hard-disk drive (HDD) controller for an HDD system is selectively configurable to operate with a first type of host system having a first logical block size and a second type of host system having a second logical block size, different from the first logical block size. Another embodiment of the disclosure is a method implemented by the HDD system.

Abstract: Methods and structure for enabling Fast Context Switching (FCS) among a plurality of FCS enhanced Serial Attached SCSI (SAS) expanders of a SAS domain. The FCS enhanced SAS expander is further adapted to detect completion of utilization of the first connection that utilizes an upstream PHY and a downstream PHY of the expander. The expander is further adapted, responsive to detecting completion, to determine whether a second connection between the initiator device and a second target device could be established utilizing the existing coupling between the upstream PHY and the downstream PHY. The expander de-couples the upstream PHY from the downstream PHY within the expander in response to determining that the second connection does not utilize the existing coupling and maintains the existing coupling in response to determining that the second connection utilizes the coupling between the upstream PHY and the downstream PHY.

Abstract: Methods and structure for migrating a logical volume with a Serial Attached SCSI (SAS) expander are provided. The expander comprises a plurality of physical links with associated transceivers (PHYs). The expander further comprises a control unit operable to select a logical volume, and to initiate migration of data from the selected logical volume to a backup logical volume. Further, the expander includes a Serial SCSI Protocol (SSP) target of the expander operable to intercept commands directed to the selected logical volume responsive to the control unit initiating the migration, and an SSP initiator of the expander that is operable to generate commands directed to the backup logical volume based on the intercepted commands, and to provide the intercepted commands to the selected logical volume.

Abstract: Methods and structure for enabling Fast Context Switching (FCS) among a plurality of FCS enhanced Serial Attached SCSI (SAS) expanders of a SAS domain. The FCS enhanced SAS expander is further adapted to detect completion of utilization of the first connection that utilizes an upstream PHY and a downstream PHY of the expander. The expander is further adapted, responsive to detecting completion, to determine whether a second connection between the initiator device and a second target device could be established utilizing the existing coupling between the upstream PHY and the downstream PHY. The expander de-couples the upstream PHY from the downstream PHY within the expander in response to determining that the second connection does not utilize the existing coupling and maintains the existing coupling in response to determining that the second connection utilizes the coupling between the upstream PHY and the downstream PHY.

Abstract: Methods and structure for migrating a logical volume with a Serial Attached SCSI (SAS) expander are provided. The expander comprises a plurality of physical links with associated transceivers (PHYs). The expander further comprises a control unit operable to select a logical volume, and to initiate migration of data from the selected logical volume to a backup logical volume. Further, the expander includes a Serial SCSI Protocol (SSP) target of the expander operable to intercept commands directed to the selected logical volume responsive to the control unit initiating the migration, and an SSP initiator of the expander that is operable to generate commands directed to the backup logical volume based on the intercepted commands, and to provide the intercepted commands to the selected logical volume.

Abstract: Methods and structure for masking of logical unit numbers (LUNs) within a switching device coupled with one or more storage enclosures. Each storage enclosure defines one or more logical volumes each identified by a LUN within the storage enclosures. The switching device gathers LUN definition information regarding each LUN defined by each storage enclosure coupled with the switching device. LUN access permission information may be provided by an administrative node/user defining a level of access permitted or denied for each host system for each LUN for each storage enclosure. The switching device then intercepts a REPORT LUNS command from any host directed to a storage enclosure and responds with only those LUNs to which the requesting host system has permitted access. Further, any other SCSI command intercepted at the switching device directed to a LUN to which the host system does not have access is modified to identify an invalid LUN.