Garbage collection for solid state disks
US8166233B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jul 24, 2009 |
| Grant date | Apr 24, 2012 |
| Priority date | — |
| Expiry date | Oct 19, 2030 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F2212/7205
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
Described embodiments provide a method of recovering storage space on a solid state disk (SSD). An index and valid page count are determined for each block of a segment of an SSD. If the valid page count of at least one block in the segment is zero, a quick clean is performed. A quick clean deallocates blocks having zero valid pages and places them in a queue for erasure. Otherwise, a deep clean is performed. A deep clean determines a compaction ratio, N-M, wherein N is a number of partially valid blocks and M is a number of free blocks required to compact the valid data from the N partially valid blocks into M entirely valid blocks. At least one data structure of the SSD is modified to refer to the M entirely valid blocks, and the N partially valid blocks are placed in the queue for erasure.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.