Management information generating method, logical block constructing method, and semiconductor memory device

摘要

A management information generating method wherein logical and physical block addresses (BAs) of continuous addresses are associated with each other in the BA translation table. When a logical block is constructed, a value is set for a maximum number of allowable defective physical blocks. A logical block having fewer defects than the set number is set usable, and a logical block having more defects than the set number is set unusable. System logical block construction is performed to preferentially select physical blocks from a plane list including a large number of usable blocks to equalize the number of usable blocks in each plane list. It is determined whether the number of free blocks is insufficient on the basis of a first management unit and whether the storage area for the indicated capacity can be reserved on the basis of the management unit different from the first unit.

主权项

1. A semiconductor memory device comprising:
a nonvolatile semiconductor memory configured to include a plurality of physical blocks, the physical blocks being units of data erasing; and a controller configured associate the physical blocks with a logical block, the controller being configured to manage the physical blocks, wherein the controller includes:
a block managing unit configured to manage, when a bad block is generated among the physical blocks, the logical block as a defective logical block, the defective logical block being associated with a plurality of physical blocks other than the bad block;a first calculating unit configured to count a number of free blocks, the free blocks being unused logical blocks in the nonvolatile semiconductor memory;a second calculating unit configured to convert a capacity of a logical block in the nonvolatile semiconductor memory into a first management size, the first management size being a size equal to or smaller than a size of a physical block, the first management size being a size larger than a size of a sector, the second calculating unit being configured to calculate a number of pieces of usable data of the first management size; anda failure determining unit configured to determine that a failure has occurred, the failure determining unit being configured to change a mode to a failure mode, when at least one of a first condition and a second condition is satisfied, the first condition being a condition in which the counted number of free blocks is less than a first threshold, the second condition being a condition in which the calculated number of pieces of data of the first management size is less than a second threshold.