Subsystem and method of reorganizing multiplexed data

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Filing Information

  • Patent Number: US6742093
  • Application Number: US10348783
  • Filing date: 01/23/2003
  • Issue date: 05/25/2004
  • Prior Publication Data:
  • Predicted expiration date: 02/24/2019
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  • U.S. Classifications: 711/162  · 707/204  · 714/6  · 710/260  · 711/161  ·
  • International Classifications: --
  • International Classifications: 711161 · 711162 · 711 4 · 714 6 · 710260 · 707204 ·
  • Related U.S. Application Data:
    This is a continuation of application Ser. No. 09/982,935 filed Oct. 22, 2001 now U.S. Pat. No. 6,615,328, which is a continuation of application Ser. No. 09/256,859 filed Feb. 24, 1999 now abandoned.
  • Foreign Priority: JP10045380 - 02/26/1998 ·
20 Claims, 8 Drawings


Abstract

Disk units operable under control of different disk control units hold the same data. Under circumstances in which data is duplexed, when data is duplexed again after data that is generally saved as backup data was accessed for reading and writing, in order to efficiently duplex data, update places of both original data and sub-data updated during the duplexing of data is interrupted are registered on an access information management table of an original disk control unit. When the original disk control unit receives a duplexing resume command, the duplexing of data may be efficiently reorganized by copying original data corresponding to an access place produced during the duplexing is interrupted from information of the access information management table to the backup data or by copying the backup data to the original data.

References Cited

U.S. Patent Documents

Document NumberAssigneesInventorsIssue/Pub Date
US5692155* International Business Machines Corporation Iskiyan et al. Nov 1997
US5845328* Ltd. Hitachi Maya et al. Dec 1998
US5875479* International Business Machines Corporation Blount et al. Feb 1999
US6044444* EMC Corporation Ofek Mar 2000
US6131148* International Business Machines Corporation West et al. Oct 2000
US6317815* EMC Corporation Mayer et al. Nov 2001
* cited by examiner

Referenced By

Document NumberAssigneeInventorsIssue/Pub Date
US6978347Hitachi, Ltd.Yasuaki Nakamura et al.Dec 2005

Patent Family

Document NumberAssigneeInventorsIssue/Pub Date
US20030110362Hitachi, Ltd.Koji Ozawa et al.Jun 2003
US6742093Hitachi, Ltd.Hitoshi Shiozawa et al.May 2004

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Independent Claims | See all claims (20)

  1. 1. A data storage device comprising: a channel unit coupled to a host; a disk control unit coupled to said channel unit for interrupting copying of data to another data storage device which corresponds to said data storage device during multiplexing, and for reading updated data stored in said another data storage device from another host during said interruption of multiplexing, and for resuming said copying of data to said another data storage device after reading said updated data; and, a disk unit controlled by said disk control unit for storing data read out from said another data storage device.
  2. 12. A data storage device comprising: a disk control unit for controlling writing or reading of data transmitted from a host, and for interrupting copying of data to another data storage device corresponding to said data storage device during multiplexing, and for reading out updated data updated in said another data storage device from another host during said interruption of multiplexing, and for resuming said copying of data to said another data storage device after reading said updated data, and a disk unit controlled by said disk control unit for storing data read out from said another data storing device.