Patent ID: 7822908
Filing Date: 2010-10-26
Classification: G06F

Abstract:
1. A communication system configured to conform to SAS standard and causing communication between one or more hosts and a storage device comprising: a multi-port bridge device including two or more SAS ports through which the multi-port bridge device communicates to hosts and a SATA port through which the multi-port bridge device communicates with a storage device through the SATA port, each said SAS ports having associated therewith an address for identifying an associated port, the multi-port bridge device operative to generate addresses unique to each SAS port and operative to communicate the port addresses, through a SAS frame to the storage device, wherein identification of SAS ports is achievable even when the storage device is inoperational, the multi-port bridge device further including a command attribute table operative to store tags, a tag being associated with a command from the hosts for identifying the storage device, the multi-port bridge device further including a command issue state machine coupled to the command buffer and a drive queue table coupled to the command issue state machine, the multi-port bridge device operative to use ‘tags’ to address the storage device, the tags being initially generated by the one or more hosts and provided to the multi-port bridge device through the two or more SAS ports, the drive queue table operative to store a plurality of tags some of which are ‘valid’ tags used for addressing the storage device, the state machine operative to re-map the stored tags so as to avoid the situation where hosts have sent the same tag, the state machine operative to search the drive queue table for the first entry where a tag is available therein and uses the found entry for addressing the storage device.