Log structured array storage subsystem using LSA directory and LSA sub-directory stored in different storage media
US5671390A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 23, 1995 |
| Grant date | Sep 23, 1997 |
| Priority date | — |
| Expiry date | May 23, 2015 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B27/329
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A method and means are disclosed in a Log Structure Array (LSA) storage subsystem for managing said subsystem without a need for an access to a complete LSA directory in a RAM. This object is achieved by maintaining (1) a subset of the LSA directory (referred to as LSA sub-directory) in a RAM where the LSA sub-directory comprises the logical track address of a predetermined number of most recently accessed logical tracks; (2) a journal of changes to the LSA directory which is maintained on a different power boundary than the LSA directory power boundary; and, (3) an array of bit maps, one bit map per segment which is used for fast garbage collection thus eliminating the need for having an access to a complete LSA directory in a RAM during garbage collection.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.