The present embodiments relate to systems and methods for implementing wear leveling in a flash memory device that emulates an EEPROM. The embodiments utilize an index array, which stores an index word for each logical address in the emulated EEPROM. The embodiments comprise a system and method for receiving an erase command and a logical address, the logical address corresponding to a sector of physical words of non-volatile memory cells in an array of non-volatile memory cells, the sector comprising a first physical word, a last physical word, and one or more physical words between the first physical word and the last physical word; when a current word, identified by an index bit, is the last physical word in the sector, erasing the sector; and when the current word is not the last physical word in the sector, changing a next index bit.

Various embodiments of the present disclosure generally relate to a memory system and an operating method thereof. According to the embodiments of the disclosed technology, the memory system may check first information indicating an execution state of a reference operation on each of the memory blocks during a preset target time period, may determine, based on the first information, at least one target memory block, among the plurality of memory blocks, as a target of a refresh operation of rewriting data stored in the target memory block and may execute a refresh operation on the target memory block.

A storage system has a memory with a multi-level cell (MLC) block and a partially-bad single-level cell (SLC) block. The storage system repurposes the partially-bad SLC block as a non-volatile read cache for data stored in the MLC block (e.g., cold data that is read relatively frequently) to improve performance of host reads. Because the original version of the data is still stored in the MLC block, the original version of the data can be read if there is an error in the copy of the data stored in the partially-bad SLC block, thus avoiding the need for extensive error-correction handling to account for the poor reliability of the partially-bad SLC block.

A non-volatile memory includes a plurality of cells each individually capable of storing multiple bits of data including bits of multiple physical pages. A controller of the non-volatile memory issues a command to perform a programming pass for a physical page among the multiple physical pages. The controller determines whether or not the programming pass took less than a minimum threshold time and no program fail status indication was received. Based on determining the programming pass took less than a minimum threshold time and no program fail status indication was received, the controller detects an under-programming error and performs mitigation for the detected under-programming error.

Systems and methods for read level tracking and optimization are described. Pages from a wordline of a flash memory device read and the raw page data read from the wordline may be buffered in a first set of buffers. The raw page data for each of the pages may be provided to a decoder for decoding and the decoded page data for each of the pages buffered in a second set of buffers. First bin identifiers may be identified for memory cells of the wordline based on the raw page data and second bin identifiers may be identified for the memory cells of the wordline based on the decoded page data. Cell-level statistics may be accumulated based on the first bin identifiers and the second bin identifiers, and a gradient may be determined for respective read levels based on decoding results for each of the pages and the cell-level statistics. Settings for the read levels may be configured in the flash memory device based on the determined gradients.

A storage system includes a non-volatile memory (NVM) device, having a memory cell array, and a storage controller. The storage controller receives a write command and data from a host and controls the NVM device to write the data in the memory cell array. Additionally, the storage controller determines a memory region of the memory cell array in which the data will be written, clusters a plurality of word lines into a plurality of groups on the basis of feature information of the plurality of word lines, rearranges an access order in units of groups according to the feature information, and accesses the word lines in the rearranged order to write the data in the memory region.

A nonvolatile memory device includes a peripheral circuit region and a memory cell region vertically connected with the peripheral circuit region, the peripheral circuit region including at least one first metal pad, and the memory cell region including at least one second metal pad directly connected with the at least one first metal pad. A method of programming the nonvolatile memory device includes: receiving a programming command, data for a plurality of pages, and an address corresponding to a selected word-line; programming the data for one of the pages to an unselected word-line; reading data of a previously programmed page from the selected word-line; and programming the data for the remaining pages and the data of the previously programmed page to the selected word-line.

A memory system includes a nonvolatile memory configured to execute one of a plurality of read operations, including a first read operation and a second read operation, and a memory controller configured to issue a read command to the nonvolatile memory to cause the nonvolatile memory to execute one of the plurality of read operations. The memory controller is configured to receive a read request, estimate a reliability level of a result of a read operation to be executed by the nonvolatile memory to read data from a physical address specified in the read request, select one of the first and second read operations to be executed first in a read sequence corresponding to the read request by the nonvolatile memory based on the estimated reliability level, and instruct the nonvolatile memory to execute the selected read operation.

An apparatus, such as a memory (e.g., a NAND memory), can have a controller, a volatile counter coupled to the controller, and a non-volatile memory array coupled to the controller. The controller can be configured to write information, other than a count of the counter, in the array each time the count of the counter has been incremented by a particular number of increments. Counts can be monotonic, non-volatile, and power-loss tolerant.

According to one embodiment, the semiconductor memory medium includes a first memory cell, a first word line coupled to the first memory cell, and a row decoder coupled to the first word line. A write operation is executed multiple times on the first memory cell within a first period from after an execution of an erase operation to an execution of a next erase operation. The write operation includes at least one of program loops each including a program operation and a verify operation. In the verify operation, the row decoder applies a verify voltage to the first word line. The verify voltage is set in accordance with a number of executed write operations on the first memory cell within the first period.