doubt retention flash nor chip

[sonicmario]

ST M29W640FT 70N6H NOR flash chip says it retains 100% data for 20 years and storage temperature –65 ~ 150 °C
What temperature is compatible with 20 years of retention?
in my case the temperature is 36C how many 100% retention data are given for this memory

[fzabkar]

My advice is to tear down every appliance or device that you wish to keep for 20 years and backup the contents of all the EEPROMs and NOR/NAND flash memories. If possible, also backup the embedded flash memory on each MCU. Then store these backups on at least three HDDs at separate locations. Backup the memories on the PCBs of each HDD for added peace of mind. Of course you would store each HDD PCB backup on the other HDDs.

If possible, read and rewrite each memory IC every year or so, for added peace of mind.

[Arch Stanton]

190 years

[sonicmario]

ironic answers not serious

[fzabkar]

How is it possible to provide a serious answer to this question? Do you think manufacturer's test their components for 20 years or 100 years before releasing them? I would think that accelerated testing regimes cannot possibly provide a definitive answer to the question of data retention. They are at best an estimate.

NOR Flash: FAQs
https://community.infineon.com/t5/Knowledge-Base-Articles/NOR-Flash-FAQs/ta-p/255345

12. The datasheet shows that data retention after 10K Program/Erase and 100K Program/Erase cycles is 20 years and 2 years, respectively. What is the average field temperature for these values?

- Generally, the assumption is 55 °C average temperature for data retention according to JEDEC.

[fzabkar]

Endurance and Data Retention Characterization of Infineon Flash Memory:

https://www.infineon.com/dgdl/Infineon-AN217979_Endurance_and_Data_Retention_Characterization_of_Infineon_Flash_Memory-ApplicationNotes-v03_00-EN.pdf