Emc Corporation

Data General Corporation

Brian K Bailey

Robert C Solomon

Douglas E Peeke

Peter B Everdell

James W Espy

Scott J Bleiweiss

Steven D Sardella

Geoffrey A Reid

Peter Yale Kushner

Darrin Haug

James M Tuttle

Andrew P Kubicki

Elizabeth H Reeves

Joseph Perry

Joseph B Shimkus

Robert Yates

Keith A P Morrissette

Robert D Maiorana

Patrick J McAdam

In a system comprising a plurality of components, characteristic data is stored on programmable read-only-memories (PROMS) on each component. The PROMs are coupled together via a simple bus, and data is retrieved from the PROMs using the bus. The collection of data from the PROMs provides the component characteristic data, and a portion of the component characteristic data is stored in one or more persistent media devices in the system, creating a last known good copy. The persistent storage device could be any device that does not lose data in the event of a loss of power.

Method and apparatus for preserving data in a high-availability system preserving device characteristic data

Described is a storage system that operates with a diskless enclosure. The diskless enclosure comprises a communication port connected to an arbitrated loop, a plurality of storage ports each being connectable to a disk module, and port bypass control circuitry. The port bypass control circuitry includes retimer circuitry for retiming communication signals passing through the communication port to and from the arbitrated loop. The port bypass control circuitry forwards retimed communication signals to the arbitrated loop without any storage port of the plurality of storage ports having a disk module connected thereto.

Storage system with a diskless enclosure

Described are a system and method of detecting an improperly connected cable in a storage system. A system includes an enclosure having boards. Each board of the enclosure has a communications port that receives a message identifying a redundant backend network to which that board is connected. The enclosure determines whether the system has an improper cable connection by determining from the messages whether the boards are connected to the same redundant backend network.

Storage system and method of detecting an improper cable connection in the storage system

A system and method of testing processor boards in which a test path is created by setting switches in distribution hubs and the devices under test. Test signals are sent through the test path and errors in the signals are used to identify faulty boards. The distribution hubs of an embodiment can detect, report and eliminate errors in the test signals. A command path from a host to the distribution hubs and devices under test is provided through a multi-terminal connector. The command path is preferably separate from the test path. A test signal generator may be included. The system may be particularly adapted for fiber channel testing.

Testing system and methods with protocol pattern injection and external verification

A method for detecting faulty equipment on a loop of disk drives in which error counts are obtained for each disk drive including an amount of invalid transmission words and/or a count of loop initialization protocols (LIPs) that have been initiated and received. Counts are obtained twice so as to detect changes to the error counts. Based on the error counts and LIP counts suspect disk drives may be recorded along with their electrical predecessor on the loop to permit expedited identification of faulty equipment.

Failure detection and isolation

A high performance data path for performing XOR on the fly. A first memory is connected to a first bus and a second memory is connected to a second bus selectively coupled to the first bus. Logic for performing an XOR can be switched into connection with the first and second bus for XORing data in a buffer with the data passed from one of the memories to the other memory. The result is replaced into the buffer to permit successive XORing. When reading from an interrelated group of disks such as a RAID 3 group, the data path permits an N-1 and go mode in which a read does not wait for data from the last disk to retrieve its data sector. If the last disk contains data (as opposed to parity) the data is obtained from the XORed data in the XOR buffer of the high performance data path. For writing data, the XOR on the fly generates the parity sector for writing at the completion of a write to an interrelated group of disks.

High performance data path with XOR on the fly

A recovery method for use in a data storage system in which a plurality of data storage devices are connected to each of two communication paths. A switch may route requests to either of the two communication paths. With one data storage controller in communication with the data storage devices over a first path and a second data storage controller in communication with the data storage devices over a second path, upon detection of a malfunction on the first path, a data storage controller may request access to the other path. Thereafter, the controller may be switched into connection with the remaining operable path so as to share that path with the other controller.

Fail-over switching system

A recovery method and fail-over switch for use in a data storage system in which a plurality of data storage devices are connected to each of two communication paths. The switch may route requests to either of the two communication paths. Switching may be accomplished by two fail-over switches connected to each other and each in connection with one of the two communication paths. With one data storage controller in communication with the data storage devices over a first path and a second data storage controller in communication with the data storage devices over a second path, the fail-over switches may be used upon detection of a malfunction on one path to switch a controller into connection with the remaining operable path so as to share that path with the other controller.

Growing community of inventors

Mendon, MA, United States of America

Brian K Bailey