Disk controller with volatile and non-volatile cache memories
US5586291A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 23, 1994 |
| Grant date | Dec 17, 1996 |
| Priority date | — |
| Expiry date | Dec 23, 2014 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F2212/312
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A disk storage subsystem includes both volatile and non-volatile portions of memory. In response to a write command from a host computer, the controller allocates a predetermined number of memory blocks in the non-volatile cache memory and allocates a corresponding number of blocks in the volatile memory. Host supplied write data is then stored in the allocated non-volatile memory blocks. The data may also be mirrored in additional non-volatile memory. Immediately thereafter the subsystem sends an acknowledge signal to the host. The subsystem then performs a DMA operation to copy the write-data from the non-volatile memory blocks to the volatile memory blocks. The write-data is then stored on a disk drive at which point the non-volatile memory may be de-allocated. Subsequent reads of the given data may be read from the volatile memory, reducing disk access time. In the event of a power failure, data stored in the non-volatile memory but not yet written to disk is preserved. In the event of a disk controller failure, the non-volatile memory modules may be transferred to a functioning disk controller for recovery.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.