System and method for striping data to magnetic tape units
First Claim
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1. An auxiliary data storage system, comprising:
- a plurality of removable media data storage units;
an array of removable volumes for mounting on the removable media data storage units;
means for mounting the array of removable volumes on the plurality of removable media data storage units;
means for accessing the array at equivalent logical locations on each of the removable volumes of the array for storage or retrieval of a data file distributed across said array of removable volumes;
means, responsive to access of an array of removable volumes, for striping data to the removable volumes by bytes with the bytes being organized into at least a first logical packet for each volume and with the logical packet for some volumes being padded if insufficient data exists to complete the logical packet; and
means, responsive to access of an array of removable volumes, for striping data to the removable volumes by logical blocks and null marks, wherein null marks are placed in a subset of the volumes if a total number of logical blocks striped to said array of removable volumes is not evenly divisible by a total number of volumes receiving striped data.
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Abstract
A plurality of removable volumes for magnetic tape units are used as array for the storage of data. First an array of removable volumes is mounted on the magnetic tape units. Then each removable volume of the array is accessed at equivalent logical locations for storage or retrieval of the data file. Responsive to access of the array, data for the data file is striped to the removable volumes of the array beginning at the equivalent location on each removable volume. Depending upon the striping format, null marks may be striped to the removable volumes receiving fewer data than other volumes. This maintains the equivalent logical location for the start of the next file.
72 Citations
18 Claims
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1. An auxiliary data storage system, comprising:
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a plurality of removable media data storage units; an array of removable volumes for mounting on the removable media data storage units; means for mounting the array of removable volumes on the plurality of removable media data storage units; means for accessing the array at equivalent logical locations on each of the removable volumes of the array for storage or retrieval of a data file distributed across said array of removable volumes; means, responsive to access of an array of removable volumes, for striping data to the removable volumes by bytes with the bytes being organized into at least a first logical packet for each volume and with the logical packet for some volumes being padded if insufficient data exists to complete the logical packet; and means, responsive to access of an array of removable volumes, for striping data to the removable volumes by logical blocks and null marks, wherein null marks are placed in a subset of the volumes if a total number of logical blocks striped to said array of removable volumes is not evenly divisible by a total number of volumes receiving striped data. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A method of storing and recovering a data file on a plurality of the removable media data storage units, the method comprising:
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mounting an array of removable volumes on the removable media data storage units; accessing the array at equivalent logical locations on each of the removable volumes of the array for storage or retrieval of a data file distributed across said array of removable volumes; responsive to access of an array of removable volumes and selection by a user or host of distributing data by bytes, striping data to the removable volumes by bytes with the bytes being organized into at least a first logical packet for each volume and with the logical packet for some volumes being padded if insufficient data exists to complete the logical packet; and responsive to access of an array of removable volumes and selection by a user or a host of a logical block organization, striping data to the removable volumes by logical blocks and null marks, wherein null marks are placed in a subset of the volumes if a total number of logical blocks striped to said array of removable volumes is not evenly divisible by a total number of volumes receiving striped data. - View Dependent Claims (10, 11, 12, 13, 14, 15)
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16. A data processing system, comprising:
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a host computer; a library of removable volumes for storage of data; a plurality of auxiliary memory drive units for accessing removable volumes; and an array of removable volumes within the library having file format conventions and labels compatible with file format conventions of the library, said array of removable volumes being striped with data for the host computer with data for a given file starting at a first volume of the array and for each volume on an identical block index, wherein said given file begins at a same sequential file on all volumes and a starting location for said given file is identified by a single location pointer also used for volumes not belonging to an array. - View Dependent Claims (17, 18)
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Specification