Multilevel, hierarchical, dynamically mapped data storage subsystem
US5155835A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Nov 19, 1990 |
| Grant date | Oct 13, 1992 |
| Priority date | — |
| Expiry date | Nov 19, 2010 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11C29/76
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
The disk drive array data storage subsystem functions as a conventional large form factor disk drive memory, using an array of redundancy groups, each containing N+M disk drives. The data storage subsystem does not modify data stored in a redundancy group but simply writes the modified data as a new record in available memory space on another redundancy group. The original data is flagged as obsolete. Virtual tracks that are least used are migrated as part of a free space collection process to low access cylinders, which are, in turn, migrated to secondary media, such as magnetic tape. The migration process is either periodic or demand driven to automatically archive little used data records.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.