摘要:
Apparatus and methods store error recovery data in different dimensions of a memory array. For example, in one dimension, block error correction codes (ECC) are used, and in another dimension, supplemental error correction codes, such as convolutional codes, are used. By using separate dimensions, the likelihood that a defect affects both error recovery techniques is lessened, thereby increasing the probability that error recovery can be performed successfully. In one example, block error correction codes are used for data stored along rows, and this data is stored in one level of multiple-level cells of the array. Supplemental error correction codes are used for data stored along columns, such as along the cells of a string, and the supplemental error correction codes are stored in a different level than the error correction codes.
摘要:
Apparatus and methods are disclosed, such as those that store data in a plurality of non-volatile integrated circuit memory devices, such as NAND flash, with convolutional encoding. A relatively high code rate for the convolutional code consumes relatively little extra memory space. In one embodiment, the convolutional code is spread over portions of a plurality of memory devices, rather than being concentrated within a page of a particular memory device. In one embodiment, a code rate of m/n is used, and the convolutional code is stored across n memory devices.
摘要:
Methods and apparatus for managing data storage in hybrid memory devices utilizing single level and multi level memory cells. Logical addresses can be distributed between single level and multilevel memory cells based on a frequency of write operations performed. Initial storage of data corresponding to a logical address in memory can be determined by various methods including initially writing all data to single level memory or initially writing all data to multilevel memory. Other methods permit a host to direct logical address writes to single level or multilevel memory cells based on anticipated usage.
摘要:
Methods and apparatus for managing data storage in memory devices utilizing memory arrays of varying density memory cells. Data can be initially stored in lower density memory. Data can be further read, compacted, conditioned and written to higher density memory as background operations. Methods of data conditioning to improve data reliability during storage to higher density memory and methods for managing data across multiple memory arrays are also disclosed.
摘要:
Methods of data handling include receiving data having a previously-generated error correction code and generating one or more error correction codes for the data, with each error correction code corresponding to the data having one or more particular bits of the data in differing data states. Such methods further include comparing the generated one or more error correction codes to the previously-generated error correction code, and if a particular one of the generated one or more error correction codes matches the previously-generated error correction code, transmitting the data having its one or more particular bits in the data states corresponding to that particular one of the generated one or more error correction codes. Methods of data handling may further include prioritizing the error correction in response to at least locations of known bad or questionable bits of the data.
摘要:
Apparatus and methods store stream-based error recovery data for a memory array, such as a NAND flash array. Conventionally, data is block coded per industry specification and stored in the memory array. Within the limits of the block code, this technique provides for correction of errors. By applying a stream-based inner code, that is, concatenating the outer block code with an outer code, the error correction can be further enhanced, enhancing the reliability of the device. This can also permit a relatively small-geometry device to be used in a legacy application.
摘要:
Methods of operating memories facilitate compensating for memory cell signal line propagation delays, such as to increase the overall threshold voltage range and non-volatile memory cell states available. Methods include selecting a memory cell signal line of a memory and characterizing the memory cell signal line by determining an RC time constant of the memory cell signal line.
摘要:
Apparatus and methods store error recovery data in different dimensions of a memory array. For example, in one dimension, block error correction codes (ECC) are used, and in another dimension, supplemental error correction codes, such as convolutional codes, are used. By using separate dimensions, the likelihood that a defect affects both error recovery techniques is lessened, thereby increasing the probability that error recovery can be performed successfully. In one example, block error correction codes are used for data stored along rows, and this data is stored in one level of multiple-level cells of the array. Supplemental error correction codes are used for data stored along columns, such as along the cells of a string, and the supplemental error correction codes are stored in a different level than the error correction codes.
摘要:
Data is read from a memory array. Before being stored in a data buffer, a Hamming code detection operation and a Reed-Solomon code detection operation are operated in parallel to determine if the data word has any errors. The results of the parallel detection operations are communicated to a controller circuit. If an error is present that can be corrected by the Hamming code correction operation, this is performed and the Reed-Solomon code detection operation is performed on the corrected word. If the error is uncorrectable by the Hamming code, the Reed-Solomon code correction operation is performed on the word.
摘要:
Controllers and memory devices are provided. In an embodiment, a controller is configured to address a non-defective column of memory cells of a memory device in place of a defective column of memory cells of the memory device in response to receiving an address of the defective column of memory cells from the memory device. In another embodiment, a memory device has columns of memory cells and is configured to receive an external address that addresses a non-defective column of memory cells of a sequence of columns of memory cells of the memory device in place of a defective column of memory cells of the sequence of columns of memory cells such that the non-defective column replaces the defective column. The non-defective column is a proximate non-defective column following the defective column in the sequence of columns that is available to replace the defective column.