Patent ID: 8862794

Claim:
A serial attached small computer system interface (SAS) input/output (I/O) control system comprising: one or more SAS agents; a plurality of physical or logical devices; one or more SAS expanders connecting the physical devices to the one or more SAS agents and mediating I/O communications between the plurality of physical or logical devices and the one or more SAS agent; each SAS expander including a plurality of Phys, wherein each Phy is associated with a particular physical device; each SAS expander comprising a plurality of configurable I/O control register bits, wherein each configurable I/O control register bit is associated with a particular physical or logical device of the plurality of physical or logical devices, wherein each configurable I/O control register bit is controllable by one or more particular SAS agents of the one or more SAS agents; wherein each SAS expander is further configured to enable SAS OPEN requests for the particular logical or physical device when the associated configurable I/O control register bit is set to a first value, and each SAS expander is further configured to disable SAS OPEN requests that are configured to leave a SAS link when the associated configurable I/O control register bit is set to a second value; wherein each SAS expander is further configured to operate the plurality of configurable I/O control register bits; and wherein each Phy is configured to return an OPEN REJECT (RETRY) response to a disabled OPEN request to delay and not cancel the disabled OPEN request when the associated particular configurable I/O control register bit is set to the second value.