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Allocation method of physical regions of a disc array to a plurality of logically-sequential data, adapted for increased parallel access to data

  • US 5,809,516 A
  • Filed: 12/26/1995
  • Issued: 09/15/1998
  • Est. Priority Date: 12/28/1994
  • Status: Expired due to Term
First Claim
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1. In a disc array which comprises:

  • a plurality of disc storage devices for storing a plurality of error correcting data groups, each error correcting data group comprising a plurality of data and error correcting code data therefor, andan array controller for controlling execution of data read requests and data write requests for said plurality of disc storage devices,each disc storage device having a plurality of storage regions each for storing either data or error correcting code data,a plurality of storage regions included in said plurality of disc storage devices being divided into a plurality of groups of storage regions,wherein storage regions belonging to each group of storage regions belong to different ones of said plurality of disc devices and store a plurality of data and error correcting code data both belonging to a same error correcting data group, in such a manner that error correcting code data belonging to different error correcting data groups are dispersed in said plurality of disc devices,a method for allocating one of said plurality of storage regions within said plurality of disc storage devices to data to be written therein, comprising the steps of;

    storing allocation status information designating a plurality of unallocated storage regions for storing data, not allocated to any data, within a plurality of storage regions within said plurality of disc storage devices; and

    allocating a plurality of unallocated storage regions which satisfy a predetermined condition, to a plurality of sequentially-ordered data to be written, said allocating being executed sequentially according to an order of said plurality of sequentially-ordered data to be written, said plurality of unallocated storage regions being selected from a plurality of unallocated storage regions designated by said stored allocation status information;

    wherein said predetermined condition comprises first and second conditions to be satisfied simultaneously;

    wherein said first condition is that said storage region allocated to each of said plurality of sequentially-ordered data to be written belongs to one of said plurality of disc storage devices which is different from any one of first and second disc storage devices, wherein said first disc storage device includes a first storage region which has been allocated to one data within a predetermined number of data preceding said each of said plurality of sequentially-ordered data to be written, said second storage device includes a second storage region which stores error correcting code data belonging to an error correcting data group stored by a group of storage regions to which said first storage region belongs;

    wherein said second condition is that a storage region which stores a particular error correcting code data belongs to one of said plurality of storage devices which is different from said first and second disc storage devices, said particular error correcting code data belonging to an error correcting data group which is stored by a group of storage regions including said storage region allocated to said each of said plurality of sequentially-ordered data to be written.

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