A storage device includes a nonvolatile memory including a plurality of first blocks having memory cells each configured to store one bit of data and a plurality of second blocks having memory cells each configured to multiple bits of data; and a controller configured to determine whether or not a number of use-completed second blocks, each of which has a first threshold number or less of valid pages, among use-completed second blocks of the plurality of second blocks, is equal to or larger than a second threshold number and to select, according to a determination result, a victim block on which garbage collection is to be performed among used-completed first blocks of the plurality of first blocks or the use-completed second blocks each having the first threshold number or less of valid pages.

A storage device is provided to comprise a memory device for storing data, a cache memory device including a first cache memory configured to cache certain data stored in the memory device and a second cache memory configured to store data evicted from the first cache memory, and a memory controller configured to receive a read request for first data from a host, evict second data from the first cache memory based on a reuse distance of the second data, store the second data in the second cache memory, load the first data to the first cache memory, and transmit the first data to the host.

A memory access method and a computer system are provided. According to the memory access method, whether to flip the to-be-stored data for storage may be determined based on quantities of “1” and “0” in data to be written into a dynamic random access memory (DRAM) and a storage mode of the DRAM, to reduce a quantity of storage cells with high electric charges in the DRAM, thereby reducing a data error probability.

A data storage device includes a nonvolatile memory including a plurality of memory blocks and page buffers for data input/output, the page buffers being electrically connected to the plurality of memory blocks, respectively, and a controller configured to, when a number of free memory blocks among the plurality of memory blocks is equal to or less than a predetermined threshold number, select, as a candidate source memory block group, memory blocks each having a number of valid pages equal to or less than a predetermined number within the nonvolatile memory, select, as a source memory block, a memory block having a minimum amount of time required to read valid data from the valid page within the candidate source memory block group and perform a garbage collection operation to the source memory block.

A key-value storage architecture with data compression is shown. During the garbage collection, the controller compresses valid pieces of key-value data to generate a piece of compressed data. Each piece of key-value data is in key-value format. The controller codes the piece of compressed data to generate a first piece of compressed key-value data that is also in key-value format, and programs the first piece of compressed key-value data into the non-volatile memory.

A storage device includes a memory device, and a memory controller configured to receive data and a log related to a property of the data from an external host, allocate a super block in which the data in the memory device is to be stored and a physical zone in the super block based on the log of the data, and store information for the log of the data stored for each physical zone and a time point at which a physical zone of a full state in which an empty area does not exist is switched to the full state. The memory controller controls the memory device to perform garbage collection according to the number of physical zones of an empty state, and selects a victim physical zone based on the information for the log of the data and a full state switch time point.

A processor may allocate a first buffer segment from a buffer pool. The first buffer segment may be configured with a first contiguous range of memory for a first data partition of a data table. The first data partition comprising a first plurality of data blocks. A processor may store the first plurality of data blocks in order into the first buffer segment. A processor may retrieve the target data block from the first buffer segment in response to a data access request for a target data block of the first plurality of data blocks.

A key-value engine may perform garbage collection for a tree or hierarchical data structure on an append-only storage device with page mappings. The key-value engine may separate hot and cold data to reduce write amplification, track extent usage using a restricted or limited amount of memory, efficiently answer queries of valid extent usage, and adaptively or selectively defragment pages in snapshots in rounds of garbage collection.

Technology for performing data duplication on data that was previously consolidated (e.g., deduplicated or merged). An example method may involve receiving a request to modify a memory page; causing the data at a first storage location to be decrypted using location dependent cryptographic input and then encrypted using a location independent cryptographic input; copying the encrypted data of the memory page from the first storage location to a second storage location; causing the encrypted data at the first and second storage locations to be decrypted using location independent cryptographic input and to each be encrypted using a different location dependent cryptographic input; updating, by the supervisor, one of the references of the plurality of memory pages from pointing to the first storage location in the physical memory to pointing to the second storage location; and modifying the memory page by altering data in the physical memory.

Provided computer-implemented methods for prioritizing cache objects for deletion may include (1) tracking, at a computing device, a respective time an externally-accessed object spends in an external cache, (2) queuing, when the externally-accessed object is purged from the external cache, the externally-accessed object in a first queue, (3) queuing, when an internally-accessed object is released, the internally-accessed object in a second queue, (4) prioritizing objects within the first queue, based on a cache-defined internal age factor and on respective times the objects spend in the external cache and respective times the objects spend in an internal cache, (5) prioritizing objects within the second queue based on respective times the objects spend in the internal cache, (6) selecting an oldest object having a longest time in any of the first queue and the second queue, and (7) deleting the oldest object. Various other methods, systems, and computer-readable media are disclosed.