Abstract: A memory system is connectable to a host and includes a nonvolatile memory including a plurality of memory cells, a data buffer connected to the nonvolatile memory, and a memory controller configured to control the nonvolatile memory and including a tag recognition circuit. The tag recognition circuit is configured to recognize whether a storage state tag is assigned to first data in the data buffer, wherein the storage state tag indicates a mode of writing the first data in the memory cells.

Abstract: A memory system is connectable to a host having a host memory and includes a non-volatile memory that stores management data, a memory controller configured to manage caching of parts of the management data in cache lines of the host memory, and a first memory configured to store a bitmap that includes a bit indicating whether the memory controller has accessed first data stored in the host memory after power was last supplied to the memory system. The first data indicates whether or not a part of the management data corresponding thereto is stored in one of the cache lines, and the memory controller is configured to perform either a first operation of reading the first data from the host memory or a second operation of reading an initial value of the first data managed by the memory controller, based on the bitmap.

Abstract: According to one embodiment, a non-volatile first memory includes a plurality of first storage areas. A second memory stores a plurality of first addresses each is address information of a second storage area. The second storage area is a first storage area in a first state. A third memory stores a counted value for the second storage area. A determiner circuit reads, at a time of a read access to the first memory, at least one of the first addresses and compares the read second address with a third address to determine whether a third storage area is in the first state. The third address indicates a location of the third storage area. The third storage area is a first storage area to be read. An update circuit increments, for the third storage area, the counted value, when the third storage area is in the first state.

Abstract: According to one embodiment, a memory system, comprises a non-volatile memory; a first memory and a second memory; and a memory controller configured to receive a first logical address from a host in a first reading, read a first address conversion table corresponding to the first logical address from the non-volatile memory, and store, in the non-volatile memory, a second address conversion table of a first state stored in the first memory in a case where the first logical address corresponds to a second logical address stored in the second memory.

Abstract: According to one embodiment, a non-volatile first memory includes a plurality of first storage areas. A second memory stores a plurality of first addresses each is address information of a second storage area. The second storage area is a first storage area in a first state. A third memory stores a counted value for the second storage area. A determiner circuit reads, at a time of a read access to the first memory, at least one of the first addresses and compares the read second address with a third address to determine whether a third storage area is in the first state. The third address indicates a location of the third storage area. The third storage area is a first storage area to be read. An update circuit increments, for the third storage area, the counted value, when the third storage area is in the first state.

Abstract: According to one embodiment, a memory system, comprises a non-volatile memory; a first memory and a second memory; and a memory controller configured to receive a first logical address from a host in a first reading, read a first address conversion table corresponding to the first logical address from the non-volatile memory, and store, in the non-volatile memory, a second address conversion table of a first state stored in the first memory in a case where the first logical address corresponds to a second logical address stored in the second memory.

Abstract: According to one embodiment, an information processing apparatus includes a host and a memory system. The host includes a main memory. The memory system includes a memory access unit and an interface unit. The memory access unit converts a first request into transmission information. The first request is a request for data transfer toward a memory region as a part of the main memory. The interface unit transmits transmission information according to an instruction from the memory access unit.

Abstract: According to one embodiment, a memory controller includes a first volatile memory, a second volatile memory, and a controller. The first volatile memory temporarily stores therein data acquired from outside. The controller controls the temporarily stored data to be transferred from the first volatile memory to a non-volatile memory, stores correspondence information of the transferred data to the non-volatile memory in the second volatile memory, and updates correspondence information stored in the non-volatile memory based on the correspondence information stored in the second volatile memory by using the first volatile memory after the data transfer as a work area. The correspondence information represents association between a logical address and a physical address of the data.

Abstract: According to one embodiment, a memory controller includes a first volatile memory, a second volatile memory, and a controller. The first volatile memory temporarily stores therein data acquired from outside. The controller controls the temporarily stored data to be transferred from the first volatile memory to a non-volatile memory, stores correspondence information of the transferred data to the non-volatile memory in the second volatile memory, and updates correspondence information stored in the non-volatile memory based on the correspondence information stored in the second volatile memory by using the first volatile memory after the data transfer as a work area. The correspondence information represents association between a logical address and a physical address of the data.

Abstract: According to one embodiment, an information processing apparatus includes a host and a memory system. The host includes a main memory. The memory system includes a memory access unit and an interface unit. The memory access unit converts a first request into transmission information. The first request is a request for data transfer toward a memory region as a part of the main memory. The interface unit transmits transmission information according to an instruction from the memory access unit.

Abstract: A memory system includes a first nonvolatile memory, a second nonvolatile memory with a longer access latency than the first nonvolatile memory, a first error correction unit, a second error correction unit, and an interface. The first nonvolatile memory stores first data and a first error correction code generated for the first data. The second nonvolatile memory stores a second error correction code which is generated for the first data with a higher correction ability than that of the first error correction code. The first error correction unit performs error correction on the first data by using the first error correction code. The second error correction unit performs error correction on the first data by using the second error correction code. The interface transmits the first data after the error correction to a host.

Abstract: According to one embodiment, a decoder of a memory controller includes: a syndrome calculating unit configured to calculate a syndrome based upon a code word read from the memory; an error locator polynomial generating unit configured to generate an error locator polynomial based upon the syndrome, and to obtain a number of errors based upon the generated error locator polynomial; and an error location calculating unit configured to calculate an error location based upon the error locator polynomial, wherein the process of the error location calculating unit is not executed, when the number of errors is not less than the maximum number of bits that can be corrected by the error locator polynomial generating unit.

Abstract: According to one embodiment, a memory controller includes an address translation information storage unit that stores plural translation information formed by classifying a correspondence between a logical address and a physical address into two or more hierarchies, a tag management unit that sores a cache line tag, which includes hierarchy information corresponding to each of the translation information stored in the translation information storage unit, and a control unit that identities whether the translation information is stored in the translation information storage unit or not by using a cache line tag.

Abstract: A storage device according to an embodiment includes first and second non-volatile semiconductor memories. In addition, the storage device includes first controller that controls the first non-volatile memory to cause the first non-volatile memory to perform processes. In addition, the storage device includes second controller that controls the second non-volatile memory to cause the second non-volatile memory to perform processes. The storage device further includes a signal line which is connected to the first controller and the second controller and through which a token is transmitted between the first controller and the second controller. The first controller is capable of controlling the first non-volatile memory while holding the token and the second controller is capable of controlling the second non-volatile memory while holding the token.

Abstract: A storage device according to an embodiment includes first and second non-volatile semiconductor memories. In addition, the storage device includes first controller that controls the first non-volatile memory to cause the first non-volatile memory to perform processes. In addition, the storage device includes second controller that controls the second non-volatile memory to cause the second non-volatile memory to perform processes. The storage device further includes a signal line which is connected to the first controller and the second controller and through which a token is transmitted between the first controller and the second controller. The first controller is capable of controlling the first non-volatile memory while holding the token and the second controller is capable of controlling the second non-volatile memory while holding the token.

Abstract: A memory system includes a first nonvolatile memory, a second nonvolatile memory with a longer access latency than the first nonvolatile memory, a first error correction unit, a second error correction unit, and an interface. The first nonvolatile memory stores first data and a first error correction code generated for the first data. The second nonvolatile memory stores a second error correction code which is generated for the first data with a higher correction ability than that of the first error correction code. The first error correction unit performs error correction on the first data by using the first error correction code. The second error correction unit performs error correction on the first data by using the second error correction code. The interface transmits the first data after the error correction to a host.

Abstract: According to one embodiment, a decoder of a memory controller includes: a syndrome calculating unit configured to calculate a syndrome based upon a code word read from the memory; an error locator polynomial generating unit configured to generate an error locator polynomial based upon the syndrome, and to obtain a number of errors based upon the generated error locator polynomial; and an error location calculating unit configured to calculate an error location based upon the error locator polynomial, wherein the process of the error location calculating unit is not executed, when the number of errors is not less than the maximum number of bits that can be corrected by the error locator polynomial generating unit.

Abstract: According to an embodiment, a semiconductor storage device includes a memory, an encoding unit that generates a parity, and a decoding unit that includes a syndrome calculating unit, an error position polynomial calculating unit, and an error searching and correcting unit, and performs an error correcting process based on data and the parity read from the memory. At the time of performing a compaction process, a process of the error searching and correcting unit is not performed, when the number of error bits acquired by an error position polynomial is equal to or less than a first threshold value based on valid data.