Memory system and method for controlling a nonvolatile semiconductor memory

摘要

A memory system includes a nonvolatile semiconductor memory having blocks, the block being data erasing unit; and a controller configured to execute; an update processing for; writing superseding data in a block, the superseding data being treated as valid data; and invalidating superseded data having the same logical address as the superseding data, the superseded data being treated as invalid data; and a compaction processing for; retrieving blocks having invalid data using a management table, the management table managing blocks in a linked list format for each number of valid data included in the block; selecting a compaction source block having at least one valid data from the retrieved blocks; copying a plurality of valid data included in the compaction source blocks into a compaction target block; invalidating the plurality of valid data in the compaction source blocks; and releasing the compaction source blocks in which all data are invalidated.

主权项

1. A memory system comprising:
a nonvolatile semiconductor memory including a plurality of storage units; a volatile semiconductor memory including a storage area; a controller configured to:
select valid data stored in first storage units;store write data in the storage area, the write data being sent from a host apparatus;write the selected valid data, as first valid data, in a second storage unit, when a sum of the valid data stored in the first storage units does not reach a size of a unit of storage;copy, as second valid data, the write data stored in the storage area, to the second storage unit, when the write data stored in the storage area reaches a size of a unit of management of the valid data; andwrite the first valid data and the second valid data stored in the second storage unit, in a third storage unit, when a total size of the first valid data and the second valid data stored in the second storage unit reaches the size of the unit of storage.