Nonvolatile memory with block management
A non-volatile, memory system technology that is used in the management of individually erasable blocks to solve complex problems
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no. 1 example
[0030] The direct data file storage technique described in the above-identified patent application creates a block list from which entries with predefined values related to the use of each block are selected. This paper uses techniques for content-addressable searches of these block lists. For this description, see the attached Figures 1 to 3 .
[0031] figure 1is a table showing block classification of memory cells based on block content. In fact, all the blocks in the memory system will be classified as shown. Three separate lists are maintained in this example: one for partial blocks, another for obsolete blocks, and a third for erased blocks.
[0032] The approved block types in this instance are as follows:
[0033] A "programmed block" has been partially programmed and contains valid data for only a single file. Some erased capacity remains in the block. It may also contain some obsolete data.
[0034] A "common block" has been partially programmed and contain...
no. 2 example
[0134] In a second example, as in the first example described above, certain blocks are individually classified according to the data they contain, and a record is maintained for these blocks. A list ordered according to the descriptor values related to the data stored in the block is maintained. The amount of valid data in a block is an example of such a descriptor value. However, in this second example, some of the structures and methods for managing blocks are different. The structures and methods of the first and second examples should be considered as alternatives, where various combinations of structures and / or techniques from the two examples are also considered part of the invention. The description of the second example focuses on the differences from the first example. Therefore, elements common to the two examples may not be described in detail with respect to the second example.
[0135] The block classification in the second instance is the same as in the fir...
no. 3 example
[0200] In a third example, a record is always maintained for every block in the memory array. This may involve one or more additional block classifications, for example, to Figure 4 The classification of the second example shown adds an additional classification for file blocks that do not contain obsolete data. Although maintaining records for each block increases the total number of records maintained, it may allow simpler structures to be used. The third example can operate similarly to the second example, except that it has a record for each block.
[0201] For example, where a record is maintained for each block, a directory entry is also maintained for each block. Directory entries have a fixed and uniform size. Thus, a directory page may contain a fixed number of entries ordered sequentially by block address. Therefore, each directory page covers a fixed block address range. Because the entries within such a page are at predetermined offsets according to their blo...
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