Storage device managing nonvolatile memory by converting logical address to physical address of nonvolatile memory
AssigneeMitsubishi Denki Kabushiki Kaisha
InventorYoshimasa Yoshimura
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Abstract
A flash memory includes a user block for storage of user data, an alternate block reserved for substitution, a conversion table for storage of a physical address of the user block corresponding to a logical address, and an alternate table for storage of a physical address of the alternate block. A controller refers to the conversion table for writing the user data to a page within the user block. If the relevant page has data already written therein, the controller refers to the alternate table and writes the user data to a page within the alternate block to use it as a new user block, and switches the original user block to an alternate block. This permits rapid rewriting of the user data.
Claims8
A storage device, comprising:
- a nonvolatile semiconductor memory having data erased in a unit of block that is formed of a plurality of pages and written in a unit of page for a page having data erased therefrom;
- and
- a control portion controlling said nonvolatile semiconductor memory;
- said nonvolatile semiconductor memory including
- a user block storing user data,
- an alternate block reserved for substitution,
- a conversion table storing a physical address of said user block corresponding to a logical address, and
- an alternate table storing a physical address of said alternate block, and
- said control portion, when referring to said conversion table for writing the user data to a page within the user block, if the relevant page has data written therein, referring to said alternate table and writing the user data to a page within said alternate block, so that said alternate block becomes a new user block, while the original user block becomes a new alternate block.
Dependencies are inferred from the claim text.