Method and apparatus for providing write recovery of faulty data in a non-redundant raid system
US6854071B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | May 14, 2001 |
| Grant date | Feb 8, 2005 |
| Priority date | — |
| Expiry date | Feb 5, 2023 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F11/0793
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A table for identifying potentially bad location addresses based on prior knowledge and performing specific operations using the table data to ensure write recovery is disclosed. A Write Recovery Table (WRT) is provided, which consists of a list of LBAs requiring such special write recovery action so that a WRITE AND VERIFY command is issued instead of a WRITE command. If the WRITE AND VERIFY command fails, the RAID controller can issue a REASSIGN BLOCKS command for the bad block and re-issue the WRITE AND VERIFY command. If WRITE AND VERIFY commands are not supported, then the system can use a READ command with the “Force Unit Access” flag bit being set to “1” to verify the written data. Further, the WRT may be combined with Bad Data Table (BDT) to reject a Read Request from the host for a matched LBA (that is listed therein) because the data in the addressed block is known incorrect when a write recovery action is not warranted.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.