Garbage collection in SSD drives
US9645922B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Sep 10, 2015 |
| Grant date | May 9, 2017 |
| Priority date | — |
| Expiry date | Nov 3, 2035 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F2212/7211
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A storage device, such as a NAND flash device, includes a controller that maintains a temperature for a plurality of data blocks, the temperature calculated according to a function that increases with a number of valid data objects in the block and recency with which the valid data objects have been accessed. Blocks with the lowest temperature are selected for garbage collection. Recency for a block is determined based on a number of valid data objects stored in the block that are referenced in a hot list of a LRU list. During garbage collection, data objects that are least recently used are invalidated to reduce write amplification.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.