Partial block data programming and reading operations in a non-volatile memory
View Patent ↗Data in less than all of the pages of a non-volatile memory block are updated by programming the new data in unused pages of either the same or another block. In order to prevent having to copy unchanged pages of data into the new block, or to program flags into superceded pages of data, the pages of new data are identified by the same logical address as the pages of data which they superceded and a time stamp is added to note when each page was written. When reading the data, the most recent pages of data are used and the older superceded pages of data are ignored. This technique is also applied to metablocks that include one block from each of several different units of a memory array, by directing all page updates to a single unused block in one of the units.
1. A method of operating a non-volatile memory system, comprising:
providing a plurality of blocks of memory storage elements that are individually erasable as a unit and which are individually organized into a plurality of pages of memory storage elements that are individually programmable together,
programming at least one page of data in one of the plurality of blocks;
programming at least one page of new data in one of said one or another of the plurality of blocks, the at least one page of new data rendering the at least one page of data to become at least one page of superceded data
identifying the at least one page of superceded data and the at least one page of new data by a common logical address,
recording an indication of a relative time of programming the at least one page of new data and the at least one page of superceded data; and
wherein the at least one page of superceded data is less than all the data contained in said one block.
2. The method of claim 1 , wherein the indication of a relative time of programming is recorded for the individual pages in which the new and superceded data are programmed, whereby the at least one page of new data is distinguishable from the at least one page of superceded data by their recorded indications of relative time of programming.
3. A method of operating a non-volatile memory system, comprising:
providing a plurality of blocks of memory storage elements that are individually erasable as a unit and which are individually organized into a plurality of pages of memory storage elements that are individually programmable together,
programming at least one page of data in one of the plurality of blocks;
programming at least one page of new data in one of said one or another of the plurality of blocks, the at least one page of new data rendering the at least one page of data to become at least one page of superceded data,
identifying the at least one page of superceded data and the at least one page of new data by a common logical address,
recording an indication of a relative time of programming the at least one page of new data and the at least one page of superceded data; and
wherein the data in at least another page of said one block that is not replaced are not copied into said one or another block as part of substituting the new data for the superceded data.
4. The method of claim 1 , wherein nothing is written into the at least one page of superceded data as part of substituting the new data for the superceded data.
5. The method of claim 1 , wherein recording an indication of a relative time of programming the new and superceded data includes storing a value of a clock at each of the times that the new and superceded data are programmed.
6. The method of claim 1 , wherein recording an indication of a relative time of programming the new and superceded data includes storing a different value of a sequence of numbers at each of the times that the new and superceded data are programmed.
7. The method of either of claim 5 or 6 , wherein storing the value indicating a relative time of programming the new and superceded data includes storing the individual values within the same pages as the new and superceded data to which the values relate.
8. The method of claim 1 , wherein programming the new data into at least one page of another said one or another of the plurality of blocks includes programming the new data into a first available unused pages within said one or another block in a predefined order.
9. The method of claim 1 , wherein identifying the at least one page of superceded data and the at least one page of new data by a common logical address includes recording at least part of the common logical address in the individual pages as overhead data.
10. The method of claim 9 , including building a table in volatile memory including multiple physical block addresses for the common logical address.
11. A method of reading data that has been updated according to claim 2 , comprising:
reading pages of data from said one block and, if new data has been programmed thereinto, said another block,
identifying any multiple pages of data that have the same logical address,
utilizing the recorded relative time of programming the new and superceded data to identify a most current of any pages having the same logical address, and
assembling data in the most current of any pages having the same logical address along with pages in said at least another page of said one block that have not been updated.
12. A method of operating a non-volatile memory system, comprising:
providing a plurality of blocks of memory storage elements that are individually erasable as a unit and which are individually organized into a plurality of pages of memory storage elements that are individually programmable together,
programming at least one page of data in one of the plurality of blocks;
programming at least one page of new data in one of said one or another of the plurality of blocks, the at least one page of new data rendering the at least one page of data to become at least one page of superceded data, wherein pages within the individual blocks are programmed in a designated order,
identifying the at least one page of superceded data and the at least one page of new data by a common logical address,
reading pages of data within said one and, if new data has been programmed thereinto, another block in a reverse order from which they were programmed, and
passing over any pages of data so read which have the same logical page address as a page whose data has already been read; and
wherein the at least one page of superceded data is less than all the data contained in said one block.
13. The method of either one of claim 11 or 12 , additionally comprising operating the individual memory storage elements with more than two storage states, thereby storing more than one bit of data in each storage element, and reading pages of data includes reading the more than two storage states from the individual memory storage elements.
14. The method of claim 1 , additionally comprising operating storage elements of the individual memory cells with more than two storage states, thereby storing more than one bit of data in each storage element.
15. The method of claim 14 , wherein the storage elements include individual floating gates.
16. The method of claim 1 , wherein the non-volatile memory system is formed within an enclosed card having an electrical connector along one edge thereof that operably connects with a host system.