Maintaining duplex-paired storage devices during gap processing using of a dual copy function

Patent 5051887 Issued on September 24, 1991. Estimated Expiration Date:

November 19, 2010. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.

Abstract Claims Description Full Text

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Inventors

Application

No. 614983 filed on 11/19/1990

US Classes:

711/162Backup

Examiners

Primary: Lee, Thomas C.
Assistant: Harrell, Robert B.

Attorney, Agent or Firm

Whitham & Marhoefer

Foreign Patent References

156179 EP. 02/12/1985
0115121 JP 09/12/1980

International Classes

G06F 013/00
G06F 012/00
G06F 012/16
G06F 011/14

Abstract

A technique is described for managing data storage devices and the data stored on them. A pair of data storage devices are maintained as identical copies. The dual copy function is provided without changing any current system or application software on the host. A set of status information is maintained for each record on the data storage devices. This status information includes information which allows only the changed records to be copied to a secondary device of the dual copy. This technique also provides high availability of data storage devices by swapping a failing data storage device with a good data storage device without host intervention. A joint array structure is used for routing host requests for information to and from the correct data storage device and keeping status information concerning the data storage devices.

Other References

Uffenbeck, John E., "Sec. 10.4 Disk Formatting", in: Uffenbeck, John E., Microcomputers and Microprocessors (Englewood Cliffs, N.J. by Prentice-Hall, Inc. (1985)), p. 499
"Site Recovery in Replicated Distributed Database Systems", B. Bhargava et al., IEEE, New York, May 1986, pp. 621-627
IBM Technical Disclosure Bulletin, vol. 29, No. 11, Apr. 1987, p. 4816, "DASD Update Processing