NAND Flash and Modern Vehicles

[mrbrian200]

Note: NOT specific to Volvo. This applies to any modern vehicle from a Nissan Versa to a Bugatti.

My question regards software data integrity over the life of a vehicle.
All modern vehicles main modules run on software atop what amounts to be a specialized programmable computer, the heart of which is not all that dissimilar to what is inside a laptop or smartphone. The software program is stored on flash memory within these various modules. A quick google reveals the type of flash memory typically used is 'automotive grade' SLC NAND and/or NOR flash. Micron is one supplier.

All flash memory is subject to cell leakage: Once a flash cell is charged, the electrons stored in the cell leak across the gate over time, causing the charge on the cell to decrease. With enough leakage, the voltage level on the cell will drift into the
neighboring region, causing the incorrect binary value to be read.

For enterprise grade SLC NAND flash the typical data retention time, or the amount of time before bit errors due to cell leakage begin to corrupt the data, at low write/erase cycles, is considered to be around 16 years at 55 degrees Celsius.

Drilling through Microns automotive flash product lines, I see they are designed to tolerate higher temperatures but I'm not seeing much in the way regarding data retention rates/time.

So, with that, does it stand to reason that people who own aging 'modern' vehicles might want to refresh this data via a full software reload on their vehicles every so often, and if so, how many years/how often? Fifteen...Twenty... ???

[matthew1]

This question is very similar to the longetivity questions surrounding optical media like CD-ROMs. How long will data last? Can they go 50 years? Or magnetic media.

Or Epson's and Canon's claims their ink/papers will go 90 years without fading... it's only conjecture based on "studies". Nobody knows. (But it helps them sell printers.)

[matthew1]

Fwiw, I'd be 1000x more likely to believe Micron's estimate on their NAND longevity than Canon's on their ink's.