US 7,444,445 B2Granted

Selectively adjusting signal compensation parameters and data rate for transmission of data through a smart cable

AssigneeInternational Business Machines Corporation

InventorsRobert A. Kubo, Gregg S. Lucas

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Abstract

A data storage domain is provided to determine a set of signal conditioning parameters for data being transmitted over smart cables in a data storage domain between an SAS switch and SAS expanders and among SAS expanders. A first expander interrogates any attached smart cables for cable persistent data and captures in a table the cable persistent data. One or more interfaces of the first expander are operated at a first data rate. The switch collects the captured cable persistent data and, in response, determines a set of signal conditioning parameters for data being transmitted on each attached smart cable. The set of signal conditioning parameters includes a first maximum data rate for each attached smart cable. The signal conditioning parameters are then set for each attached smart cable in accordance with the set of determined signal conditioning parameters, whereby the data storage domain is tuned for optimum signal transmission.

Claims16

Dependent claims

A data storage domain, comprising:

a serial attached SCSI (SAS) switch comprising one or more SAS interfaces, including a first SAS interface operable at least at a first data rate;
a first SAS expander comprising one or more SAS interfaces;
including a second SAS interface operable at least at the first data rate;
a first smart cable attached between the first SAS interface and the second SAS interface and having a non-volatile memory storing persistent cable data including information relating to the signal degradation characteristics of the first smart cable;
the first SAS expander further comprising a first processor programmed to:
interrogate the first smart cable and any other smart cable attached between the first SAS expander and another SAS device in the data storage domain, the interrogation comprising a request for the cable persistent data of each attached smart cable;
and
capture in a table the cable persistent data of each attached smart cable;
the SAS switch further comprising a second processor programmed to:
direct that the one or more interfaces of the SAS switch and of the first SAS expander operate at the first data rate;
collect the cable persistent data captured in the table;
in response to the collected cable persistent data, determine a set of signal conditioning parameters for data being transmitted on each attached smart cable, the set of signal conditioning parameters including a maximum data rate;
and
transmit a command to the first processor to set the signal conditioning parameters for each attached smart cable in accordance with the set of determined signal conditioning parameters.

11 more elements

A method for adjusting signal compensation parameters for transmission of data between a serial attached SCSI (SAS) switch and one or more SAS expanders in a data storage domain through smart cables having a non-volatile memory storing cable persistent data information relating to the signal degradation characteristics of the smart cable, each SAS expander having one or more SAS interfaces operable at least at a first data rate, the method comprising:

directing that a first SAS expander interrogate any attached smart cables for the cable persistent data of each attached smart cable;
capturing in a table the cable persistent data of each smart cable attached to the first SAS expander;
operating the one or more interfaces of the first SAS expander at the first data rate;
collecting the captured cable persistent data in the SAS switch;
in response to the collected cable persistent data, determining a set of signal conditioning parameters for data being transmitted on each attached smart cable, the set of signal conditioning parameters including a first maximum data rate;
and
setting the signal conditioning parameters for each attached smart cable in accordance with the set of determined signal conditioning parameters, whereby the data storage domain is tuned for optimum signal transmission.

4 more elements

A computer program product of a computer readable medium usable with a programmable computer, the computer program product having computer-readable code embodied therein for adjusting signal compensation parameters for transmission of data between a serial attached SCSI (SAS) switch and one or more SAS expanders in a data storage domain through smart cables having a non-volatile memory storing cable persistent data information relating to the signal degradation characteristics of the smart cable, each SAS expander having one or more SAS interfaces operable at least at a first data rate, the computer-readable code comprising instructions for:

directing that a first SAS expander interrogate any attached smart cables for the cable persistent data of each attached smart cable;
capturing in a table the cable persistent data of each smart cable attached to the first SAS expander;
operating the one or more interfaces of the first SAS expander at the first data rate;
collecting the captured cable persistent data in the SAS switch;
in response to the collected cable persistent data, determining a set of signal conditioning parameters for data being transmitted on each attached smart cable, the set of signal conditioning parameters including a first maximum data rate;
and
setting the signal conditioning parameters for each attached smart cable in accordance with the set of determined signal conditioning parameters, whereby the data storage domain is tuned for optimum signal transmission.

4 more elements

Dependencies are inferred from the claim text.