A method includes moving data in a defect range from a defective area of a data storage medium to a reserve area of the data storage medium, and identifying the defect range by an address of a start of the defect range and a defect length. A logical address table is updated with the address of the start of the defect range, the defect length and an offset to the reserve area.

A method for diagnosing memory, performed by a storage system, is provided. The method includes writing and reading through a communication channel to and from flash memory of each of a plurality of flash memory devices and a static random-access memory (SRAM) register of each of the plurality of flash memory devices. The method includes analyzing errors in read data from the reading through the communication channel, identifying types of errors among flash memory errors, SRAM register errors, and communication channel errors, based on the analyzing, and indicating at least one error and type of error from the read data.

A storage array includes a plurality of hard disks, where each of the hard disks is divided into a plurality of chunks, and a plurality of chunks of different hard disks form a chunk group by using a redundancy algorithm. The storage array obtains fault information of a faulty area in a first hard disk, and determines a faulty chunk storing the lost data according to the fault information. The storage array recovers the data in the faulty chunk by using another chunk in a chunk group to which the faulty chunk belongs and stores the recovered data in a recovered chunk. The recovered chunk is located in a second hard disk which is not a hard disk for forming the chunk group.

Systems and methods for proactive transfer of stored data between storage zones to avoid anticipated bit rot are provided. In embodiments, a method includes: determining that one or more quality prediction parameters of a storage zone of a data storage device meet a predetermined threshold for user access or adjacency to another storage zone determined to be unhealthy; and initiating a proactive refreshing of the storage zone based on the determining that the storage zone meets the predetermined threshold, the proactive refreshing of the storage zone including: reading all data in the storage zone; determining that no errors have occurred during the reading of the data; and based on the determination that no errors have occurred, moving all of the data of the storage zone to a new storage zone.

A storage array includes a plurality of hard disks, each of the hard disks is divided into a plurality of chunks, and a plurality of chunks of different hard disks form a chunk group by using a redundancy algorithm. The storage array obtains fault information of a faulty area in a first hard disk, and determines a faulty chunk storing the lost data according to the fault information. The storage array recovers the data in the faulty chunk by using another chunk in a chunk group to which the faulty chunk belongs and stores the recovered data in a recovered chunk. The recovered chunk is located in a second hard disk which is not a hard disk for forming the chunk group.

According to one embodiment, a magnetic disk device includes a magnetic disk, a first magnetic head and a second magnetic head that are moved independently of each other, a first controller chip, a second controller chip, and a third memory. The first controller chip includes a first processor and a first memory, and controls the first magnetic head. The second controller chip includes a second processor and a second memory, and controls the second magnetic head. Management information is stored in the third memory. The first controller chip is connected to the third memory. The second controller chip is connected to the third memory via the first controller chip. The second controller chip saves the management information into the second memory.

According to one embodiment, a magnetic disk device includes a magnetic disk, a first magnetic head and a second magnetic head that are moved independently of each other, a first controller chip, a second controller chip, and a third memory. The first controller chip includes a first processor and a first memory, and controls the first magnetic head. The second controller chip includes a second processor and a second memory, and controls the second magnetic head. Management information is stored in the third memory. The first controller chip is connected to the third memory. The second controller chip is connected to the third memory via the first controller chip. The second controller chip saves the management information into the second memory.

A method includes moving data in a defect range from a defective area of a data storage medium to a reserve area of the data storage medium, and identifying the defect range by an address of a start of the defect range and a defect length. A logical address table is updated with the address of the start of the defect range, the defect length and an offset to the reserve area.

A storage control device includes a processor which performs first copy of copying first data stored in a first storage device into a first backup region upon detecting a failure presage in the first storage device. The processor performs first write of writing second data specified in a first write request to the first storage device and second write of writing the second data into the first backup region upon receiving the first write request while performing the first copy. The processor performs second copy of copying third data stored in the first backup region to a second storage device upon completing the first copy. The processor performs third write of writing fourth data specified in a second write request to the second storage device in place of the first storage device upon receiving the second write request after completion of the second copy.

The present disclosure includes systems and methods for reducing rewrite overhead in a sequential access storage system. The method may comprise writing a data set to a sequential access medium using a magnetic head, wherein the data set comprises a plurality of encoded data blocks, classifying each of the plurality of encoded data blocks on the sequential access medium into one of at least three classes of write quality, and rewriting the encoded data blocks in a rewrite area of the sequential access medium based at least in part on the write quality class. In some embodiments, the at least three classes of write quality may comprise a hard rewrite class for which rewrites are necessary to prevent data loss, a soft rewrite class for which rewrites are desirable but not necessary, and a no rewrite class for which no rewrite is needed or desired.