DATA WRITING METHOD FOR STORAGE DEVICE

摘要

PROBLEM TO BE SOLVED: To provide a method by which a writing performance in a storage device having a nonvolatile memory unit.SOLUTION: A data writing method for a storage device including a nonvolatile memory unit having a memory cell array constituted by nonvolatile memory cells, includes the steps of: receiving a writing request and writing data associated with the writing request; detecting, in response to the writing request, the number of usable free blocks at the memory cell array; allocating a log block by the unit of a block when the number of detected free blocks is smaller than a threshold value, and allocating a log block by the unit of a physical block or by the unit of a sub block smaller than the physical block when the number of detected free blocks is equal to or more than a threshold value; and writing writing data in an allocated log block.