# US 10,872,638 B2 · Data storage system and method based on data temperature > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,872,638 B2 - Document ID: US10872638B2 - Status: Granted - Kind: B2 - Application number: 16/724,081 - Filed: 2019-12-20 - Published: 2020-05-07 - Granted: 2020-12-22 - Earliest claimed: 2017-06-26 - Assignees: Western Digital Technologies, Inc. - Applicants: Western Digital Technologies, Inc. - Inventors: Jingfeng Yuan; James M. Higgins; Jeff Whaley - Web page: https://patentgrep.com/patent/US10872638B2 ## CPC - G11C 5/005: {Circuit means for protection against loss of information of semiconductor storage devices} - G11C 5/025: {Geometric lay-out considerations of storage- and peripheral-blocks in a semiconductor storage device (geometrical lay-out of the components in integrated circuits, geometrical lay-out of the components in integrated circuits H10D89/10)} - G11C 7/04: with means for avoiding disturbances due to temperature effects - G11C 7/24: Memory cell safety or protection circuits, e.g. arrangements for preventing inadvertent reading or writing; Status cells; Test cells - G11C 11/40626: {Temperature related aspects of refresh operations} - G11C 29/12: Built-in arrangements for testing, e.g. built-in self testing [BIST] {or interconnection details} - G11C: STATIC STORES (semiconductor memory devices H10B) ## Abstract The subject technology performs the following in a storage system including memory dies, where each memory die includes its own temperature sensor. The subject technology determines a temperature of each of the memory dies based on a temperature reading from each memory die's temperature sensor. The subject technology determines whether data is hot data or cold data, where hot data is more likely to be changed after it is written than cold data. In response to determining that the data is hot data, the subject technology stores the data in a memory die with a relatively higher temperature than another one of the memory dies. Further, in response to determining that the data is cold data, the subject technology stores the data in a memory die with a relatively cooler temperature than another one of the memory dies. ## Claims ### Claim 1 A data storage system, comprising: a plurality of memory devices; and a controller configured to cause: determining when to start data retention recycling on a memory-device-by-memory-device basis based on a temperature of each of the plurality of memory devices; determining whether data is hot data or cold data; and when the data is cold data, storing the data in a first one of the plurality of memory devices, wherein the first one of the plurality of memory devices is located farther away from the controller than a second one of the plurality of memory devices, wherein cold data is less likely to be changed after it is written than hot data. ### Claim 2 (depends on 1) The data storage system of claim 1, wherein when the data is hot data, the controller is configured to cause: storing the data in the second one of the plurality of memory devices, wherein the second one of the plurality of memory devices is located closer to the controller than the first one of the plurality of memory devices. ### Claim 3 (depends on 1) The data storage system of claim 1, wherein each of the plurality of memory devices comprises a temperature sensor, and wherein the determining when to start data retention recycling comprises: determining when to start data retention recycling on a memory-device-by-memory-device basis based on a temperature reading of each respective temperature sensor. ### Claim 4 (depends on 1) The data storage system of claim 1, wherein a quality of the first one of the plurality of memory devices is lower than a quality of the second one of the plurality of memory devices. ### Claim 5 (depends on 4) The data storage system of claim 4, wherein a quality of a first group of the plurality of memory devices is lower than a quality of a second group of the plurality of memory devices, wherein the first group comprises the first one of the plurality of memory devices, and wherein when the data is cold data, the controller is configured to cause: storing the data in the first group to reduce an amount of data retention recycling for the first group. ### Claim 6 (depends on 1) The data storage system of claim 1, wherein the first one of the plurality of memory devices has a cooler temperature than the second one of the plurality of memory devices. ### Claim 7 (depends on 1) The data storage system of claim 1, wherein at least one of the plurality of memory devices comprises a three-dimensional memory. ### Claim 8 (depends on 1) The data storage system of claim 1, wherein the data is received from a host. ### Claim 9 (depends on 1) The data storage system of claim 1, wherein the data is recycle data. ### Claim 10 A method for a data storage system, comprising: determining when to start data retention recycling on a memory-device-by-memory-device basis based on a temperature of each of a plurality of memory devices; determining whether data is hot data or cold data; and when the data is cold data, storing the data in a first one of a plurality of memory devices, wherein the first one of the plurality of memory devices is located farther away from a controller than a second one of the plurality of memory devices, wherein cold data is less likely to be changed after it is written than hot data. ### Claim 11 (depends on 10) The method of claim 10, wherein when the data is hot data, the method comprises: storing the data in the second one of the plurality of memory devices, wherein the second one of the plurality of memory devices is located closer to the controller than the first one of the plurality of memory devices. ### Claim 12 (depends on 10) The method of claim 10, wherein each of the plurality of memory devices comprises a temperature sensor, and wherein the determining when to start data retention recycling comprises: determining when to start data retention recycling on a memory-device-by-memory-device basis based on a temperature reading of each respective temperature sensor. ### Claim 13 (depends on 10) The method of claim 10, wherein the first one of the plurality of memory devices has a cooler temperature than the second one of the plurality of memory devices. ### Claim 14 (depends on 10) The method of claim 10, wherein at least one of the plurality of memory devices comprises a three-dimensional memory. ### Claim 15 (depends on 10) The method of claim 10, wherein a quality of the first one of the plurality of memory devices is lower than a quality of the second one of the plurality of memory devices. ### Claim 16 (depends on 15) The method of claim 15, wherein a quality of a first group of the plurality of memory devices is lower than a quality of a second group of the plurality of memory devices, wherein the first group comprises the first one of the plurality of memory devices, and wherein when the data is cold data, the method comprises: storing the data in the first group to reduce an amount of data retention recycling for the first group. ### Claim 17 A data storage system, comprising: means for determining when to start data retention recycling on a memory-device-by-memory-device basis based on a temperature of each of a plurality of memory devices; means for determining whether data is hot data or cold data; and when the data is cold data, means for storing the data in a first one of a plurality of memory devices, wherein the first one of the plurality of memory devices is located farther away from a controller than a second one of the plurality of memory devices, wherein cold data is less likely to be changed after it is written than hot data. ### Claim 18 (depends on 17) The data storage system of claim 17, wherein when the data is hot data, the data storage system comprises: means for storing the data in the second one of the plurality of memory devices, wherein the second one of the plurality of memory devices is located closer to the controller than the first one of the plurality of memory devices. ### Claim 19 (depends on 17) The data storage system of claim 17, wherein the first one of the plurality of memory devices is configured to have a cooler temperature than the second one of the plurality of memory devices. ### Claim 20 (depends on 17) The data storage system of claim 17, wherein each of the plurality of memory devices comprises a temperature sensor, and wherein the means for determining when to start data retention recycling comprises: means for determining when to start data retention recycling on a memory-device-by-memory-device basis based on a temperature reading of each respective temperature sensor.