Abstract: Methods and associated structure for utilizing multiple ports or PHYs comprising a SAS wide port to improve transmission bandwidth utilization for a single large I/O request. In one aspect hereof, a large I/O request is broken into a plurality of smaller I/O requests to be distributed over multiple PHYs or ports of a configured wide SAS port. The number of smaller I/O requests may be any number up to the maximum number of PHYs or ports comprising the SAS wide port. In another aspect hereof, the size of a large I/O request may be compared against a threshold value to determine whether the large request should be broken into smaller requests. The threshold value may be determined in accordance with features and aspects hereof either statically or dynamically based on workloads assigned to, and utilization of, the configured SAS wide port.

Abstract: Methods and structures within a SAS expander for initiating communication with one or more SAS initiators in a SAS domain to inform the initiators of sensed changes in the domain without the need for a full SAS Discovery process. In one aspect hereof, the expander may transmit a vendor unique BROADCAST primitive to inform SAS initiators that they should initiate a vendor unique SMP or SSP exchange with the expander to determine changes to the SAS domain. In another aspect hereof, the SAS initiator may respond as an SMP or SSP target device in response to initiation of vendor unique SMP or SSP exchanges by the expander. The expander may report to initiators regarding sensed changes in the domain and/or statistics regarding operation of the expander or other elements of the domain.

Abstract: Methods and structures within a SAS expander for monitoring bandwidth utilization of a SAS wide port associated with the expander and for effecting reconfiguration of the wide port to improve SAS domain performance. In one aspect, a SAS expander may monitor utilization of a wide port of the expander. If the wide port is over-utilized, the expander may inform a SAS initiator of the need for one or more additional links to be configured in the wide port. If the wide port is under-utilized, the expander may reconfigure the wide port by disabling a link to reduce power consumption associated with that link. If the wide port is later over-utilized, a previously disabled link may be re-enabled by the expander to restore available bandwidth. Disabled links of a wide port may also be reported to a SAS initiator to be reconfigured by the initiator for use in another communication path.

Abstract: Improved methods and structures for testing of SAS components, in situ, in a SAS domain. A first SAS component is adapted to generate stimuli such as error conditions to elicit a response to the error condition from a second SAS component coupled to the first in the intended SAS domain configuration. In one aspect, a SAS device controller generates stimuli applied to a SAS expander coupled thereto and verifies proper response from the SAS expander. In another aspect, a SAS expander generates stimuli applied to a SAS device controller coupled thereto and verifies proper response from the SAS device controller. Stimuli may be generated by custom circuits or firmware/software within the first component. Vendor specific SAS SMP transactions may be used to cause the first component to enter the special verification mode.

Abstract: Methods and structures within a SAS expander for detecting link level errors in PHYs of a SAS expander to reduce overhead bandwidth utilization of SAS links between SAS initiators and SAS expanders. In one aspect hereof, a SAS expander self monitors the error status registers of its own PHYs over an internal path that does not use bandwidth of the attached SAS links. When a link level error is so detected the SAS expander may initiate actions and/or report the error to a SAS initiator to thereby reduce he potential for lost data integrity. Where multiple SAS expanders are configured in a SAS domain fabric, each expander may monitor its PHYs or one expander may be designated a master and monitor PHYs of all expanders in the fabric.

Abstract: Methods and structures within a SAS expander for testing SAS devices and other SAS expanders in the SAS domain. Testing devices and expanders in the domain by operations performed within a SAS expander in the domain relieves the burden of such processing in attached host systems and adds flexibility for scheduling processing for test operation of devices and expanders in the domain. In one aspect hereof, the testing may be performed by a master SAS expander configured in the domain. The SAS expander may initiate testing of devices following completion of the SAS discovery process. Testing may also be initiated in response to events in the SAS domain not typically detected by attached host systems.

Abstract: Systems and methods for analyzing data passing between an SAS/SATA device and a plurality of other devices are presented. A system includes a plurality of physical interfaces configured for passing data between the SAS/SATA device and the other devices. The system also includes a test interface, or test PHY, configured for coupling to the physical interfaces for analysis of the data passing through those physical interfaces. The test PHY may be integrally configured with the SAS/SATA device and may substantially minimize alteration of characteristic impedance caused by external analysis of the data. The system may also include a multiplexer for selectively coupling the PHYs to the test PHY.

Abstract: Methods and associated structure for utilizing multiple ports or PHYs comprising a SAS wide port to improve transmission bandwidth utilization for a single large I/O request. In one aspect hereof, a large I/O request is broken into a plurality of smaller I/O requests to be distributed over multiple PHYs or ports of a configured wide SAS port. The number of smaller I/O requests may be any number up to the maximum number of PHYs or ports comprising the SAS wide port. In another aspect hereof, the size of a large I/O request may be compared against a threshold value to determine whether the large request should be broken into smaller requests. The threshold value may be determined in accordance with features and aspects hereof either statically or dynamically based on workloads assigned to, and utilization of, the configured SAS wide port.

Abstract: Improved methods and structures for testing of SAS components, in situ, in a SAS domain. A first SAS component is adapted to generate stimuli such as error conditions to elicit a response to the error condition from a second SAS component coupled to the first in the intended SAS domain configuration. In one aspect, a SAS device controller generates stimuli applied to a SAS expander coupled thereto and verifies proper response from the SAS expander. In another aspect, a SAS expander generates stimuli applied to a SAS device controller coupled thereto and verifies proper response from the SAS device controller. Stimuli may be generated by custom circuits or firmware/software within the first component. Vendor specific SAS SMP transactions may be used to cause the first component to enter the special verification mode.