Abstract: An apparatus having mapping and interface circuits. The mapping circuit (i) generates a coded item by mapping write unit bits using a modulation or recursion of past-seen bits, and (ii) calculates a particular state to program into a nonvolatile memory cell. The interface circuit programs the cell at the particular state. Two normal cell states are treated as at least four refined states. The particular state is one of the refined states. A mapping to the refined states mitigates programming write misplacement that shifts an analog voltage of the cell from the particular state to an erroneous state. The erroneous state corresponds to a readily observable illegal or atypical write sequence, and results in a modified soft decision from that calculated based on the normal states only. A voltage swing between the particular state and the erroneous state is less than between the normal states.

Abstract: An apparatus having a memory and a controller is disclosed. The memory is configured to (i) program a protected lower unit in a lower page of a location, (ii) generate a corrected lower unit by correcting the protected lower unit using a first error correction code and (iii) program a protected upper unit in an upper page of the location based on the corrected lower unit. The controller is configured to generate the protected upper unit by encoding an upper write data item using a second error correction code. The controller is on a separate die as the memory.

Abstract: Described embodiments provide a media controller that processes requests including a logical address and address range. A map of the media controller determines physical addresses of a media associated with the logical address and address range of the request. The map is a multi-level map having a plurality of leaf-level map pages that are stored in the media, with a subset of the leaf-level map pages stored in a map cache. Based on the logical address and address range, it is determined whether a corresponding leaf-level map page is stored in the map cache. If the leaf-level map page is stored in the map cache, a cache index and control indicators of the map cache entry are returned in order to enforce ordering rules that selectively enable access to a corresponding leaf-level map page based on the control indicators and a determined request type.

Abstract: An apparatus includes one or more error-correction decoders, a buffer, at least one direct memory access (DMA) engine, and at least one processor. The buffer may be configured to store data to be decoded by the one or more error-correction decoders. The at least one DMA engine may couple the buffer and the one or more error-correction decoders. The at least one processor may be enabled to send messages to the at least one DMA engine. The messages may be configured to deliver DMA control information and corresponding datapath control information. Data may be read from the buffer based upon the DMA control information and delivered to the one or more error-correction decoders along with the corresponding datapath control information. The one or more error-correction decoders may be enabled to decode the data read from the buffer according to the corresponding datapath control information.

Abstract: A method of associating a logical block address with a physical location in a non-volatile memory includes (A) in response to a write request comprising a respective logical block address in a logical block address space and respective data to be written to the non-volatile memory, determining a physical location in the non-volatile memory to store the respective data of the write request, (B) adding an entry to a journal, such that the added entry trails any entries already in the journal and the added entry has a respective logical block address field set to the respective logical block address of the write request and a respective physical location field set to the determined physical location, and (C) updating one of a plurality of second-level map pages in a two-level map according to the respective logical block address of the write request with the determined physical location.

Abstract: An apparatus having mapping and interface circuits. The mapping circuit (i) generates a coded item by mapping write unit bits using a modulation or recursion of past-seen bits, and (ii) calculates a particular state to program into a nonvolatile memory cell. The interface circuit programs the cell at the particular state. Two normal cell states are treated as at least four refined states. The particular state is one of the refined states. A mapping to the refined states mitigates programming write misplacement that shifts an analog voltage of the cell from the particular state to an erroneous state. The erroneous state corresponds to a readily observable illegal or atypical write sequence, and results in a modified soft decision from that calculated based on the normal states only. A voltage swing between the particular state and the erroneous state is less than between the normal states.

Abstract: An apparatus comprising a memory and a controller. The memory may be configured to process a plurality of read/write operations. The memory comprises a plurality of memory units each having a size less than a total size of the memory. The controller may be configured to perform a first error correction code decoding on the memory units using a plurality of initial log likelihood ratio values. The controller may be configured to count a number of unsatisfied checks if the first error correction code decoding fails. The controller may be configured to generate a plurality of measured log likelihood ratio values if the number of unsatisfied checks is below a threshold. The plurality of measured log likelihood ratio values are (a) based on calculations using decoded bits of the first error correction code decoding, and (b) used to perform a second error correction code decoding on the memory units.

Abstract: An apparatus having a memory and a controller is disclosed. The memory is configured to store a codeword. The controller is configured to (i) determine one or more least-reliable bit positions in a soft-decision version of the codeword in response to failing to decode a hard-decision version of the codeword, (ii) generate a trial codeword by selecting at random a respective value in one or more trial positions among the least-reliable bit positions in the hard-decision codeword and (iii) perform a hard-decision decoding of the trial codeword.

Abstract: Scalable control/management data structures enable optimizing performance and/or attempting to achieve a particular performance target of an SSD in accordance with host interfacing, number of NVM devices, NVM characteristics and size, and NVM aging and performance decline. Pre-scaled data structures are included in SSD controller firmware loadable at system initialization. Static data structure configurations enable load-once-operate-for-product-lifetime operation for consumer applications. Dynamic configurations provide sequences of data structures pre-scaled to optimize operation as NVM ages and performance declines. Pre-configured adjustments in data structure size included in consecutive configurations periodically replace earlier configurations at least one time during product lifetime, producing a periodic rescaling of data structure size to track changes in aging NVM.

Abstract: Higher-level redundancy information computation enables a Solid-State Disk (SSD) controller to provide higher-level redundancy capabilities to maintain reliable operation in a context of failures of non-volatile (e.g. flash) memory elements during operation of an SSD. A first portion of higher-level redundancy information is computed using parity coding via an XOR of all pages in a portion of data to be protected by the higher-level redundancy information. A second portion of the higher-level redundancy information is computed using a weighted-sum technique, each page in the portion being assigned a unique non-zero “index” as a weight when computing the weighted-sum. Arithmetic is performed over a finite field (such as a Galois Field). The portions of the higher-level redundancy information are computable in any order, such as an order based on order of read operation completion of non-volatile memory elements.

Abstract: The present disclosure is directed to a system for dynamically adaptive caching. The system includes a storage device having a physical capacity for storing data received from a host. The system may also include a control module for receiving data from the host and compressing the data to a compressed data size. Alternatively, the data may also be compressed by the storage device. The control module may be configured for determining an amount of available space on the storage device and also determining a reclaimed space, the reclaimed space being according to a difference between the size of the data received from the host and the compressed data size. The system may also include an interface module for presenting a logical capacity to the host. The logical capacity has a variable size and may include at least a portion of the reclaimed space.

Abstract: An apparatus comprising a memory and a controller. The memory is configured to process a plurality of read/write operations. The memory comprises a plurality of memory unit granularities each having a size less than a total size of the memory. The controller is configured to process a plurality of I/O requests to the memory units of the memory that are not marked as bad on a memory unit list. The controller is configured to track a plurality of bad blocks of the memory. The controller is configured to determine which of the memory units to mark as bad based on a test of whether a unit of memory larger than a block of the memory has failed. The test is based on a threshold of the bad blocks in the unit of memory.

Abstract: An apparatus includes a plurality of memory dies and a controller. The controller may be communicatively coupled to the plurality of memory dies and configured to utilize multiple copies of a root record containing system data during a boot-up process. The multiple copies of the root record are stored using at least two of the plurality of memory dies.

Abstract: An SSD controller dynamically adjust read thresholds in a NVM to reduce errors due to device threshold voltage distribution shifts, thus improving performance, reliability, and/or cost of a storage sub-system, such as an SSD. In a first aspect, the controller periodically performs offline tracking on a portion of the NVM. The controller reads a representative sub-portion with current read thresholds. If the read meets a condition, then the controller reads the sub-portion with sample read thresholds, estimates the device threshold voltage distributions, and adjusts the current read thresholds of the portion to calculated new operating read thresholds of the sub-portion. In a second aspect, the portion includes data with a known statistical average number of zero and/or one bits.

Abstract: An apparatus comprising a memory and a controller. The memory may be configured to store data. The controller may process a plurality of input/output requests to read/write to/from the memory. The controller may generate read data by performing a hard-decision decode on a codeword received from the memory. If the hard-decision decode fails, the controller may enter an error-recovery process comprising a plurality of recovery procedures. At least one of the recovery procedures may apply an inter-cell interference cancellation technique. The error-recovery process may (a) determine parameters for a soft-decision decode by performing one of the recovery procedures on the codeword, (b) execute the soft-decision decode using the parameters from the recovery procedure performed to generate the read data and (c) if the soft-decision decode fails, repeat (a) and (b) using a next one of the recovery procedures.

Abstract: An apparatus includes a device interface, a micro-sequencer, and a programmable sequence memory. The device interface may be configured to process a plurality of read/write operations to/from one or more non-volatile memory devices. The micro-sequencer may be configured to communicate with the device interface. The programmable sequence memory is generally readable by the micro-sequencer. In response to the apparatus receiving a command, (a) the micro-sequencer executes a set of instructions starting at a location in the programmable sequence memory according to the command and (b) the micro-sequencer is enabled to perform at least a portion of the command according to a protocol of the one or more non-volatile memory devices, when the one or more non-volatile memory devices are coupled to the device interface.

Abstract: An apparatus includes a non-volatile memory and a controller. The controller is operatively coupled to the non-volatile memory and configured to perform read and write operations on the non-volatile memory using codewords as a unit of read access. The controller includes an error correction engine configured to perform an error correction on codewords read from the non-volatile memory, and, if the error correction fails, to perform one or more retry procedures. The controller is further configured to perform one or more background procedures as a result of the error correction or one or more of the retry procedures not being successful and send an error message as a result of all of the retry procedures not being successful. The one or more background procedures are directed to determining a cause of the error correction failure.

Abstract: An apparatus having a nonvolatile memory and a controller. The memory stores information in multiple pages. The information includes data units and headers. Each data unit is associated with a respective identifier in an address space of the apparatus and a respective location in the memory, has a respective header having the respective identifier, and is associated with a respective time stamp. Multiple headers include ones of the time stamps. The controller is configured to (i) read information stored in the pages, (ii) determine an order in which the data units were written based on the time stamps, (iii) locate based on the order (a) each last-written occurrence of the respective identifiers and (b) the respective locations of the data units associated with the last-written occurrences, and (iv) rebuild a map of the controller according to the respective locations of each last-written occurrence of each respective identifier.

Abstract: An apparatus includes a controller and an adaptive error correction code decoder. The controller may be configured to read data from and write data to a memory device. The controller may be further configured to write data in a two-step process, which includes (i) after writing data to a least significant bit (LSB) page, checking the data stored in the LSB page using a first strength error correction code (ECC) decoding process and (ii) after writing data to a most significant bit (MSB) page associated with the LSB page, checking the data stored in both the LSB and MSB pages using a second strength error correction code (ECC) decoding process.

Abstract: A Solid-State Disk (SSD) controller enables dynamic higher-level redundancy mode management with independent silicon elements to provide graceful degradation as non-volatile (e.g. flash) memory elements fail during operation of an SSD implemented by the controller. Higher-level error correction provides correction of lower-level uncorrectable errors. If a failure of one of the non-volatile memory elements is detected, then the higher-level error correction is dynamically transitioned from operating in a current mode to operating in a new mode. The transition includes one or more of reducing free space available on the SSD, rearranging data storage of the SSD, recovering/storing failed user data (if possible), and determining/storing revised higher-level error correction information. Operation then continues in the new mode. If another failure of the non-volatile memory elements is detected, then another transition is made to another new mode.