Using a virtual device to access data as it previously existed in a mass data storage system
US6073222A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Mar 16, 1999 |
| Grant date | Jun 6, 2000 |
| Priority date | — |
| Expiry date | Mar 16, 2019 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F2201/82
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A system and method for using a virtual device established at a computer system to access data as it existed at a selected moment in a mass storage system associated with the computer system, regardless of whether new data has been written to the mass storage system. When an original data block is to be overwritten in the mass storage system with a new data block, the original data block is first preserved in a preservation memory associated with the computer system. The preservation memory thereby preserves the original data block as it existed at the selected moment. A virtual device established at the computer system provides access to data as it existed at the selected moment. This data may include original data blocks preserved in the preservation memory and other original data blocks that remain in the mass storage device, and which have not been overwritten with new data. In order to provide access to the data, the virtual device accesses the preservation memory to obtain those original data blocks that have been preserved therein and also accesses the mass storage device to obtain those original data blocks that remain in the mass storage device.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.