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Comment by NikolaNovak | Hacker News Reader

I don't understand this. Most laptops will have internal / ssd temperatures over 50C, and yet data usually lasts for years?

>>"client class SSD must maintain its data integrity at the defined BER for only 500 hours at 52°C (less than 21 days) or 96 hours at 66°C (only four days)."

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Those are powered on when the laptop is on.

Right, but through which mechanism does that maKe a difference? Does controller periodically rewrite all contents? In other words how, does being powered-on increase retention of static data?

Yes, it does precisely that.

Also all of these are minimum requirements. They don't actually imply much, except about the state of technology when the statement was written. Flash has been improving very quickly on all axes.

And yet there are still people who will post about the good old days and the evils of MLC, as if current SSDs were not demonstrably better in every way.

They aren't. Write endurance is significantly lower than SLC, it's just compensated for by lots of write leveling.

More precisely, endurance and retention become exponentially lower with each additional bit stored per cell, while capacity only increases multiplicatively.

They are better. SLC is improving as much as MLC. The ratio of speed, durability, and capacity is the same between SLC/MLC/TLC, but modern MLC is faster and more durable than 5-year-old SLC.

Exactly. And I do not care what the low-level bit performance is if the device-level performance is better.

>modern MLC is faster and more durable than 5-year-old SLC

great April fools joke

You are probably writing this from a computer using a TLC SSD. Outside of applications that need extreme latency, pure SLC has almost completely disappeared from the storage world. From materials science to management algorithms, a lot has advanced in flash technology in terms of durability.

It's true that TLC and MLC have for good reason displaced SLC. However, in no way are they even anywhere near the old SLC in durability. ~5 years old SLC literally had 100 times more write endurance (as in, how many times you can rewrite each bit, not total amount of writes in the drive) than typical modern TLC.

That is pretty much true, and it's pretty much the only stat that hasn't improved. However, write endurance isn't really a factor in terms of data durability. It has to do more with the drive's ability to continue being written than with the safety of data that has already been written. If your drive goes read-only or loses capacity, that has to do with write endurance. Neither of those involve data loss.

Citation needed

I still remember the bubble memory system that would someday replace HDD back in the 80s

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