Provided are a memory controller and memory system having an improved threshold voltage distribution characteristic and an operating method of the memory system. As a write request of data with respect to a first block is received, an erase program interval (EPI) is determined denoting a time period elapsed after erasure of the first block. When the determined EPI is equal to or less than a reference time, data is programmed to the first block based on a first operation condition selected from among a plurality of operation conditions. when the When the determined EPI is greater than the reference time, the data is programmed to the first block based on a second operation condition selected from among the plurality of operation conditions.

Flash memory on a flash memory device is virtualized using compression that is native to the flash memory device. Through compression, the flash memory device is used to logically store more data in a virtual address space that is larger than the physical address space of the flash memory device. Physical storage capacity of a flash memory device may prevent further storage of data even when the virtual address space is not fully populated. Because compressibility may vary, the extent to which the virtual address space may be populated before physical storage capacity is reached varies. The approaches for virtual memory described herein rely on the memory device client to monitor when this point is reached. In addition, the memory device client is responsible for freeing space as needed to accommodate subsequent requests to store data in the flash memory.

A System, Computer Program Product, and Computer-executable method for managing cache de-staging on a data storage system wherein the data storage system provides a Logical Unit (LU), the System, Computer Program Product, and Computer-executable method including dividing the LU into two or more extents, analyzing each of the two or more extents, creating a cache de-staging policy based on the analysis, and managing cache de-staging of the LU based the cache de-staging policy.

A read cache management method and apparatus based on a solid state drive, and the method includes: determining whether a read request hits a first queue and a second queue (S101); if both the first queue and the second queue are missed, selecting and deleting an eliminated data block from the first queue (S102); if the eliminated data block is in a stored state, inserting the eliminated data block into the second queue (S103); and determining a target data block in a lower-level storage medium, and inserting the target data block into the first queue, (S104). According to the foregoing read cache management method and apparatus based on the solid state drive, a hit ratio of the solid state drive can be increased, a data write count of the solid state drive can be reduced, and service life of the solid state drive can be extended.

A data processing method based on a quasi-cyclic LDPC includes: when a size of service data is less than a magnitude of information bit of the quasi-cyclic LDPC, calculating a difference value between the magnitude of the information bit of the quasi-cyclic LDPC and the size of the service data, and filling the service data with the same amount of known data as the difference value (S103); coding the filled service data to obtain redundancy check data corresponding to the service data (S104); and sending the service data and the redundancy check data to a corresponding physical location in the storage unit (S105). It ensures that when a code length of the quasi-cyclic LDPC is constant, the code length ideally adapts to internal space of the storage unit, and the quasi-cyclic LDPC has a relatively high error correction capability, thereby improving reliability and service life of the storage unit.

A system may include a plurality of memory cells and a processor. The plurality of memory cells may include a plurality of physical locations at which data is stored. The processor may be configured to determine whether to swap physical locations of data stored at logical block addresses in the first logical block address collection and physical locations of data stored at logical block addresses in the second logical block address collection. The processor may be further configured to, in response to determining to swap the physical locations of the data, swap the physical locations of the data stored at the logical block addresses in the first logical block address collection and the physical locations of the data stored at the logical block addresses in the second logical block address collection.

A system for reducing stress on a memory device that has multiple memory blocks. The system includes a counting unit for incrementing count values respectively associated with the memory blocks. Each of the count values indicates the number of times the associated memory block has been erased. A controller monitors the count values. Upon detecting that a count value associated with a first memory block reaches a predefined threshold, the controller selects a second memory block from the memory blocks to be swapped with the first memory block based on a count value associated with the second memory block.

Methods and apparatuses for optimizing the performance of a storage system comprise a FLASH storage system, a hard drive storage system, and a storage controller. The storage controller is adapted to receive READ and WRITE requests from an external host, and is coupled to the FLASH storage system and the hard drive storage system. The storage controller receives a WRITE request from an external host containing data and an address, forwards the received WRITE request to the FLASH storage system and associates the address provided in the WRITE request with a selected alternative address, and provides an alternative WRITE request, including the selected alternative address and the data received in the WRITE request, to the hard drive storage system, wherein the alternative address is selected to promote sequential WRITE operations within the hard drive storage system.

A device may comprise a plurality of non-volatile memory devices configured to store a plurality of physical pages and a controller coupled thereto, configured to program and read data to and from the plurality of non-volatile memory devices. The data may be stored in a plurality of logical pages (L-Pages) of non-zero length at starting addresses within the plurality of physical pages. The controller may be configured to execute first and second commands to indicate that first and second physical locations within the plurality of non-volatile memory devices no longer contain valid data and are now free space. This may be done by carrying out first and second virtual write operations of first and second L-Pages of a predetermined length at first and second unique addresses within a virtual address range that does not correspond to any of the physical pages, and accounting for an amount of free space gained as a result of executing the commands.

Logical to physical tables each including logical to physical address translations for first logical addresses can be stored. Logical to physical table fragments each including logical to physical address translations for second logical address can be stored. A first level index can be stored. The first level index can include a physical table address of a respective one of the logical to physical tables for each of the first logical addresses and a respective pointer to a second level index for each of the second logical addresses. The second level index can be stored and can include a physical fragment address of a respective logical to physical table fragment for each of the second logical addresses.