Host-available device block map for optimized file retrieval from serpentine tape drives
US6349356B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Dec 10, 1997 |
| Grant date | Feb 19, 2002 |
| Priority date | — |
| Expiry date | Dec 10, 2017 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B2220/95
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
Optimizing the retrieval of blocks of data from a tape media of a longitudinal serpentine tape drive. A device block map (DBM) is retrieved from the tape media and stored in memory. The DBM comprises a table having one or more rows and one or more columns for each block of data stored on the tape media. The columns are selected from the group comprising a wrap column, a position column, a logical block column, and a file identifier column. One or more retrieval paths for requested blocks of data are determined from an image of the physical layout of the requested blocks on the tape media generated by linear interpolation of the DBM stored in memory. Each of the retrieval paths comprises an ordered sequence of the blocks of data and the manner in which the tape media is to be traversed to accomplish the retrieval of the ordered sequence. A sum of distances is determined for each of the retrieval paths and an optimal one of the retrieval paths is selected based on the determined sum of distances. Thereafter, the blocks of data are retrieved from tape media using the optimal retrieval path.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.