Adaptive power failure recovery
US5889933A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jan 30, 1997 |
| Grant date | Mar 30, 1999 |
| Priority date | — |
| Expiry date | Jan 30, 2017 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F11/1441
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A RAID system that uses non-volatile random access memory (NVRAM) to greatly reduce the chance of loss of data due to an AC power failure. This RAID system has two write modes. In a normal write mode, a host computer receives a write confirmation once an array controller receives data from the host computer. In a safe write mode, however, the array controller copies to NVRAM all data received from the host computer for writing to disk drives. In this safe write mode, the array controller sends the write confirmation to the host computer only after storing the data in NVRAM. To switch appropriately between the normal and safe write modes, the array controller polls a power-out flag provided by a UPS (uninterruptable power supply) to determine whether there has been an AC power failure. The array controller switches between the two write modes depending on the status of the power-out flag.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.