Kabushiki Kaisha Toshiba

Kioxia Corporation

Yoko Masuo

Hironobu Miyamoto

Taichiro Yamanaka

Yosuke Mitsumasu

Wataru Okamoto

Kazuya Kitsunai

Akinori Harasawa

Motohiro Matsuyama

Takahisa Kaihotsu

Gen Ohshima

Yoshimasa Aoyama

Shingo Kikukawa

Hiromi Hoshino

A memory system connectable to a host includes a nonvolatile memory and a controller. The nonvolatile memory includes physical blocks. The controller is configured to assign each of a plurality of block groups, each block group including a predetermined number or more of the physical blocks, to one of categories. The controller assigns block groups having a total capacity equal to a fraction of the overprovisioning capacity that is equal to a first threshold value, to the first category, and block groups having a total capacity equal to a remaining part of the overprovisioning capacity to the third category. When an overprovisioning ratio falls below a second threshold value, the controller reassigns one or more block groups in the third category to the first category.

Memory system and method for controlling the same

According to one embodiment, the controller periodically executes a first operation. The controller selects a first mode or a second mode in the first operation. In a case where the first mode is selected, the controller reads pieces of data that are stored in contiguous memory locations, respectively, that are included in a first physical page or a second physical page. The first physical page is included in a first physical block of a first die. The second physical page is included in a second physical block of a second die. In a case where the second mode is selected, the controller reads first data stored in one memory location of the first physical page and second data stored in one memory location of the second physical page.

Memory system and controlling method

According to one embodiment, a memory system includes a controller which controls garbage collection for preparing one or more free blocks by writing valid data read from N blocks to one or more blocks of less than the N. The controller calculates a performance ratio between writing of data in response to a request from a host device and writing of data for the garbage collection in accordance with a data writable capacity remaining in a nonvolatile memory, calculates an average performance ratio from calculated performance ratios of M generations including a calculated latest performance ratio, and adjusts a performance cycle of the garbage collection by applying one of the calculated latest performance ratio and the calculated average performance ratio.

Memory system and garbage collection control method

According to one embodiment, a memory system includes a nonvolatile memory and a controller. The nonvolatile memory includes blocks. The controller controls the nonvolatile memory. The controller acquires a write amount to the nonvolatile memory in a first period. The controller calculates an estimated amount of writing to the nonvolatile memory in the first period. The controller changes, when the write amount is larger than the estimated amount by a first threshold value or more, one or more parameters used for writing of data to the nonvolatile memory.

Memory system and control method

According to one embodiment, a memory system includes a nonvolatile memory and a controller. The nonvolatile memory includes a plurality of blocks. The controller controls an operation of writing data to the nonvolatile memory and an operation of reading data to the nonvolatile memory. The controller includes a first processor and a second processor. The first processor executes a first process of creating one or more free blocks by transferring valid data in N blocks (where N is a natural number greater than or equal to two) to blocks of number less than N. The second processor executes a second process of transferring valid data including data which needs refresh in M blocks (where M is a natural number greater than or equal to one) to blocks of number less than or equal to M.

According to one embodiment, a data storage device includes a first controller, a second controller, and a third controller. The first controller performs a control operation of writing data of a first data unit to a storage area in a flash memory and reading the data of the first data unit from the storage area. The second controller carries out migration processing of measuring a data amount of valid data stored in storage areas of a second data unit that is a data erase processing unit.

Data storage device, memory control method, and electronic device with data storage device

According to one embodiment, a memory system includes a NAND-type flash memory and a memory controller. The memory controller includes a monitoring module and a determination module. The monitoring module acquires an elapsed time from the start of data erase of a first block in the NAND-type flash memory. The determination module determines whether the elapsed time has exceeded a reference time before completion of the data write in the first block.

Memory system and memory controller

A memory system has a storage unit having two or more parallel read/write processing elements and non-volatile data recording areas for a logical block divided into a plurality of logical pages, and a control unit that generates log information for each unit of data written into the recording areas, determines for each logical page a log information recording area from a group of recording areas of the logical page, and controls the parallel operation elements to write the log information generated for a logical page into the log information recording area of the logical page and the data of the logical page into the other recording areas of the group of recording areas of the logical page.

Memory system and control method thereof

According to one embodiment, a memory system includes a NAND-type flash memory and a memory controller. A comparison module of the memory controller compares a first threshold voltage distribution of a first memory area with a second threshold voltage distribution of the first memory area acquired earlier than the first threshold voltage distribution, if an error is detected in data read from the first memory area. An error factor determination module of the memory controller determines a cause of the error based on the comparison result, and inhibits a data move operation of moving data of the first memory area to the second memory area based on the determination result.

Memory system having NAND-type flash memory and memory controller with shift read controller and threshold voltage comparison module

According to one embodiment, a data storage apparatus includes a flash memory and a controller. The controller includes a compaction processor. The compaction processor performs the compaction processing on the flash memory, to dynamically set a range of compaction processing targets based on a number of available blocks and an amount of valid data in each of the blocks, and to search the range of compaction processing targets for blocks each with a relatively small amount of valid data as the target blocks for the compaction processing.

Data storage apparatus and method for compaction processing

According to one embodiment, a memory device includes a memory, a memory interface, a command generator, an access command returning module and a command progress manager. The memory interface accesses the memory in parallel in accordance with access commands. The command generator speculatively issues access commands to the memory interface. The access command returning module returns access commands already issued to the memory interface and unexecuted at a time of occurrence of an error, through corresponding purge responses. The command progress manager updates command progress management information such that the command progress management information indicates the oldest one of the unexecuted access commands. The command generator reissues the returned unexecuted access commands to the memory interface based on the updated command progress management information.

Memory device configured to execute plural access commands in parallel and memory access method therefor

According to one embodiment, a command generator sequentially and speculatively issues channel-by-channel access commands to a memory interface in a predetermined access process. A purger returns a series of unexecuted already-issued access commands using a purge response if an error occurs in any of memory accesses via a plurality of channels. A command progress manager updates command progress information such that the command progress on each of the plurality of channels returns to a position specified in an oldest access command of a series of the returned access commands issued to the channel. The command generator issues the channel-by-channel access commands including the oldest access command to the memory interface based on the updated command progress information.

Memory device having multiple channels and method for accessing memory in the same

According to one embodiment, a valid-cluster search module searches valid clusters included in first blocks, in each of channels, for compaction. A read command generator generates read commands used to read, in parallel, valid clusters to be migrated to a second block. The valid clusters searched in each of the channels comprise the valid clusters to be migrated. The valid clusters to be migrated correspond to a number of clusters simultaneously written to the second block and to a second number of channels in a first number of channels. A determination module determines the second number of channels corresponding to read commands to be generated next based on a situation of issuance of the read commands.

Memory system having multiple channels and method of generating read commands for compaction in memory system

According to one embodiment, an error correction channel determination module determines, a channel to be allocated to a logical page as an error correction channel so that each of a plurality of channels is allocated to a uniform number of logical pages as the error correction channel. A command list generation module generates a list of write commands each specifying that a corresponding logical page is to be written using, in parallel, channels included in the plurality of channels and excluding the error correction channel, based on the determination of the channel to be allocated to the corresponding logical page as the error correction channel. A command list issue module issues the list of the write commands.

Growing community of inventors

Iruma, Japan

Yoko Masuo