Non-volatile memory and method with non-sequential update block management

Abstract

In a nonvolatile memory with block management system that supports update blocks with non-sequential logical units, an index of the logical units in a non-sequential update block is buffered in RAM and stored periodically into the non-volatile memory. In one embodiment, the index is stored in a block dedicated for storing indices. In another embodiment, the index is stored in the update block itself. In yet another embodiment, the index is stored in the header of each logical unit. In another aspect, the logical units written after the last index update but before the next have their indexing information stored in the header of each logical unit. In this way, after a power outage, the location of recently written logical units can be determined without having to perform a scanning during initialization. In yet another aspect, a block is managed as partially sequential and partially non-sequential, directed to more than one logical subgroup.

Description

CROSS REFERENCE TO RELATED APPLICATIONS [0001] This application is a continuation-in-part of U.S. patent application Ser. No. 10 / 750,155, filed on Dec. 30, 2003.FIELD OF THE INVENTION [0002] This invention relates generally to non-volatile semiconductor memory and specifically to those having a memory block management system with efficient handling of update data in a block. BACKGROUND OF THE INVENTION [0003] Solid-state memory capable of nonvolatile storage of charge, particularly in the form of EEPROM and flash EEPROM packaged as a small form factor card, has recently become the storage of choice in a variety of mobile and handheld devices, notably information appliances and consumer electronics products. Unlike RAM (random access memory) that is also solid-state memory, flash memory is non-volatile, and retaining its stored data even after power is turned off. Also, unlike ROM (read only memory), flash memory is rewritable similar to a disk storage device. In spite of the higher ...

AI Technical Summary

Benefits of technology

[0022] The efficient use of system resource allows multiple logical groups to be updated concurrently. This further increases efficiency and reduces overheads. Alignment for Memory Distributed Over Multiple Memory Planes

[0032] In one embodiment, after two copies of a given data have been programmed in an earlier programming pass, a subsequent programming pass avoids programming the memory cells storing at least one of the two copies. In this way, at least one of the two copies will be unaffected in the event the subsequent programming pass aborts before completion and corrupts the data of the earlier pass.

Problems solved by technology

Thus, when a logical group is being updated, the distribution of logical units (and also the scatter of memory units that the updates obsolete) are limited in range.

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