Tape emulating disk based storage system and method
AssigneeOverland Storage, Inc.
InventorsJohn Matze, Michael Reider, Kenneth Geist, Daniel Davies
Life of this patent
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Abstract
A data protection and storage system includes an array of disk drives for data storage. Data is received for storage on the disk drive via an interface that is configured to emulate a tape drive interface. A virtual tape data structure is created and stored on the disk drives.
Claims11
A data storage system comprising:
- at least one hard disk drive comprising a magnetic data storage area partitioned into a plurality of data storage sectors;
- wherein at least one data storage sector stores virtual tape header data comprising information defining data storage sectors allocated to a virtual tape;
- wherein at least one data storage sector allocated to said virtual tape stores an entry table comprising information defining data storage sectors allocated to one or more individual records associated with said virtual tape;
- and
- wherein at least one data storage sector allocated to said individual data records stores at least some of said one or more individual data records.
A method of appending a record to a virtual tape comprising:
- loading virtual tape header information from a data field stored on a hard disk drive;
- reading the total number of logical blocks stored on said virtual tape from said header;
- setting a current block number as one plus the total number of logical blocks stored on said virtual tape;
- setting a current sector of said virtual tape to an end of data sector stored in said header;
- reading a current entry table specified in the header;
- allocating an entry in the current entry table for use;
- writing a data record on sectors defined by the allocated entry.
A method of reading or writing over a desired data record at a desired block number on a virtual tape comprising:
- determining data storage sectors associated with said block, said determining comprising:
- reading a current entry table defining stored block numbers associated with said entry table;
- updating said current entry table with a previous or subsequent entry table if said desired block number is not associated with said current entry table;
- repeating said reading and updating until an entry table associated with said desired block number is stored as said current entry table;
- and
- reading said current entry table to identify said sectors;
- and reading or writing over one or more of said data storage sectors.
A method of emulating data storage on a magnetic tape media using one or more hard disk drives, said method comprising:
- allocating a set of logical sectors of said one or more hard disk drives to a virtual tape;
- allocating a first subset of said set of logical sectors to at least one table, wherein said at least one table stores information allocating a second subset of said set of logical sectors to data records stored on said virtual tape.
Dependencies are inferred from the claim text.