# US 2017/0255502 A1 · Storage control apparatus, storage apparatus, and storage control method > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2017/0255502 A1 - Document ID: US20170255502A1 - Status: Published application - Kind: A1 - Application number: 15/505,674 - Filed: 2015-07-09 - Published: 2017-09-07 - Earliest claimed: 2014-09-03 - Assignees: Sony Corporation - Applicants: Sony Corporation - Inventors: YASUSHI FUJINAMI; KENICHI NAKANISHI; TSUNENORI SHIIMOTO; TETSUYA YAMAMOTO; TATSUO SHINBASHI; HIDEAKI OKUBO; HARUHIKO TERADA; KEN ISHII; HIROYUKI IWAKI; MATATOSHI HONJO - Web page: https://patentgrep.com/patent/US20170255502A1 ## CPC - G06F 11/076: {by exceeding a count or rate limit, e.g. word- or bit count limit} - G06F 11/0727: {in a storage system, e.g. in a DASD or network based storage system (drivers for digital recording or reproducing units G06F3/06; circuits for error detection or correction within digital recording or reproducing units G11B20/18; for distributed storage of data in networks, e.g. transport arrangements for network file system [NFS], storage area networks [SAN] or network attached storage [NAS], H04L67/1097)} - G06F 11/079: {Root cause analysis, i.e. error or fault diagnosis (in a hardware test environment G06F11/22; in a software test environment G06F11/36)} - G06F 11/1048: {using arrangements adapted for a specific error detection or correction feature} - G06F 12/16: Protection against loss of memory contents {(contains no material, see G06F11/00)} - G11C 29/00: Checking stores for correct operation {; Subsequent repair}; Testing stores during standby or offline operation - G11C 29/44: Indication or identification of errors, e.g. for repair - G11C 11/16: using elements in which the storage effect is based on magnetic spin effect - G11C 13/00: Digital stores characterised by the use of storage elements not covered by groups G11C11/00, G11C23/00, or G11C25/00 - G11C 2029/0407: {on power on} - G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N) - G11C: STATIC STORES (semiconductor memory devices H10B) ## Abstract Detecting a defective cell in a memory in consideration of an error property difference depending on the storage state. A determination unit determines whether there is a possibility of defect for each of unit-of-storages on a memory cell formed with a non-volatile memory. The non-volatile memory undergoes either a reset operation that transitions a state from a low resistive state (LRS) to a high resistive state (HRS) or a set operation that transitions the state from the high resistive state to the low resistive state. The determination unit determines a unit-of-storage in which the number of errors in predetermined one of the reset operation and the set operation has exceeded a predetermined standard, as a unit-of-storage suspected of having a defect. ## Claims ### Claim 1 A storage control apparatus comprising a determination unit configured to determine a unit-of-storage in which the number of errors in predetermined one of a reset operation and a set operation of a non-volatile memory toward a memory cell has exceeded a predetermined standard, as a unit-of-storage suspected of having a defect. ### Claim 2 (depends on 1) The storage control apparatus according to claim 1, wherein the determination unit determines a unit-of-storage in which a total value of the number of errors in the reset operation and the number of errors in the set operation has exceeded a predetermined standard and the number of errors in the predetermined one of the operations has exceeded a predetermined standard, as a unit-of-storage suspected of having a defect. ### Claim 3 (depends on 1) The storage control apparatus according to claim 1, wherein the determination unit determines a unit-of-storage in which a total value of the number of errors in the reset operation and the number of errors in the set operation has exceeded a predetermined standard by predetermined times and the number of errors in the predetermined one of the operations at the last time of the predetermined number of times has exceeded a predetermined standard, as a unit-of-storage suspected of having a defect. ### Claim 4 (depends on 1) The storage control apparatus according to claim 1, wherein the determination unit determines that a writing error has occurred in a unit-of-storage in a case where a total value of the number of errors in the reset operation and the number of errors in the set operation has exceeded a predetermined standard and the number of errors in the predetermined one of the operations has not exceeded a predetermined standard. ### Claim 5 (depends on 1) The storage control apparatus according to claim 1, wherein the determination unit determines the unit-of-storage suspected of having a defect as an unavailable unit-of-storage. ### Claim 6 (depends on 1) The storage control apparatus according to claim 1, further comprising a management unit configured to reconfirm the unit-of-storage determined as a unit-of-storage suspected of having a defect and to manage, in accordance with the result, the unit-of-storage as an unavailable unit-of-storage. ### Claim 7 (depends on 6) The storage control apparatus according to claim 6, wherein, at the time of performing the reconfirmation, in a case where writing is performed again toward the unit-of-storage and the unit-of-storage is determined again as a unit-of-storage suspected of having a defect, the management unit manages the unit-of-storage as an unavailable unit-of-storage. ### Claim 8 (depends on 6) The storage control apparatus according to claim 6, wherein the management unit performs the reconfirmation toward the unit-of-storage when the number of the unit-of-storage determined as a unit-of-storage suspected of having a defect has exceeded a fixed number. ### Claim 9 (depends on 6) The storage control apparatus according to claim 6, wherein, when the management unit performs the reconfirmation, the determination unit determines a unit-of-storage in which the number of errors in the predetermined one of the operations has exceeded a standard higher than the predetermined standard, as the unit-of-storage suspected of having a defect. ### Claim 10 (depends on 1) The storage control apparatus according to claim 1, wherein the determination unit selects the predetermined standard for the number of errors in the predetermined one of the operations, from among a plurality of candidates. ### Claim 11 (depends on 10) The storage control apparatus according to claim 10, wherein the determination unit selects the predetermined standard from among the plurality of candidates in accordance with a state over time in which the non-volatile memory is used. ### Claim 12 (depends on 10) The storage control apparatus according to claim 10, wherein the determination unit selects the predetermined standard from among the plurality of candidates in accordance with a predetermined identifier of the non-volatile memory. ### Claim 13 (depends on 1) The storage control apparatus according to claim 1, wherein the determination unit determines a unit-of-storage in which each of the number of errors in the reset operation and the number of errors in the set operation has exceeded a predetermined standard and the number of errors in the predetermined one of the operations has exceeded a predetermined standard, as a unit-of-storage suspected of having a defect. ### Claim 14 (depends on 1) The storage control apparatus according to claim 1, wherein the determination unit determines a unit-of-storage in which a weighted sum of the number of errors in the reset operation and the number of errors in the set operation has exceeded a predetermined standard and the number of errors in the predetermined one of the operations has exceeded a predetermined standard, as a unit-of-storage suspected of having a defect. ### Claim 15 (depends on 1) The storage control apparatus according to claim 1, wherein, when the number of errors in the predetermined one of the operations is in a fixed state not exceeding the predetermined standard, the determination unit determines the unit-of-storage as a unit-of-storage having a possibility of transitioning to a unit-of-storage suspected of having a defect. ### Claim 16 (depends on 1) The storage control apparatus according to claim 1, wherein, when the determination unit processes an erase request of erasing all bits in a unit-of-storage, the determination unit performs determination as the unit-of-storage suspected of having a defect in a case where the number of errors in the predetermined one of the operations has exceeded a standard lower than the predetermined standard. ### Claim 17 A storage apparatus comprising: a memory cell formed with a non-volatile memory; and a determination unit configured to determine a unit-of-storage in which the number of errors in predetermined one of a reset operation and a set operation toward the memory cell has exceeded a predetermined standard, as a unit-of-storage suspected of having a defect. ### Claim 18 (depends on 17) The storage apparatus according to claim 17, further comprising a counter configured to count each of the number of errors in the reset operation and the number of errors in the set operation. ### Claim 19 A storage control method comprising: a procedure of obtaining the number of errors in predetermined one of a reset operation and a set operation of a non-volatile memory toward a memory cell; and a procedure of determining a unit-of-storage in which the number of errors in the predetermined one of the operations has exceeded a predetermined standard, as a unit-of-storage suspected of having a defect.