Method and managing bad memory blocks in a nonvolatile memory device, and nonvolatile-memory device implementing the management method

Abstract

A method for managing bad memory blocks of a nonvolatile-memory device, in which the available memory blocks are divided into a first set, formed by addressable memory blocks that are to be used by a user, and a second set, formed by spare memory blocks that are to replace bad addressable memory blocks, and in which the bad addressable memory blocks are re-mapped into corresponding spare memory blocks. The re-mapping of the bad addressable memory blocks envisages: seeking bad spare memory blocks; storing the logic address of each bad spare memory block in a re-directing vector in a position corresponding to that of the bad spare memory block in the respective set; seeking bad addressable memory blocks; and storing the logic address of each bad addressable memory block in a free position in the re-directing vector.

Description

BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] The present invention relates to a method for managing bad memory blocks in a nonvolatile-memory device, and to a nonvolatile-memory device implementing the management method. [0003] 2. Discussion of Related Art [0004] As is known, nonvolatile-memory devices having an architecture of a NAND type have a memory array divided into memory blocks, each of which is in turn divided into sub-blocks referred to as pages. Each page is formed by a given number of bytes, the majority of which, approximately 95%, define the so-called data area, while the remaining bytes define an area reserved to the storage of given information (“page spare area”). [0005] Nonvolatile-memory devices having an architecture of a NAND type can be divided into two major categories according to the number of bad memory blocks that they contain: the first category comprises so-called good nonvolatile-memory devices, which do not contain bad memory blo...

AI Technical Summary

Benefits of technology

[0014] One aim of the present invention is to provide a method for managing bad memory blocks in a nonvolatile-memory device, implementation of which will call for a reduced occupation of memory.

Problems solved by technology

Generally, however, the re-directing table involves a rather high occupation of memory, so that its storage typically entails a considerable reduction in the amount of memory actually available to users.

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