[vlovich123]

Converting a QLC chip into an SLC is not planned obsolescence. It’s a legitimate tradeoff after analyzing the marketplace that existing MTBF write lifetimes are within acceptable consumer limits and consumers would rather have more storage.

Edit: and to preempt the “but make it an option”. That requires support software they may not want to build and support requests from users complaining that toggling SLC mode lost all the data or toggling QLC mode back on did similarly. It’s a valid business decision to not support that kind of product feature.

[Dylan16807]

And for the vast majority of use cases, even if QLC wears out TLC would be fine indefinitely. Limiting it to SLC capacity would be ridiculous.

[userbinator]

I have USB drives with good old SLC flash, whose data is still intact after several decades (rated for retention of 10 years at 55C after 100K cycles - and they have not been cycled anywhere near that much.)

and consumers would rather have more storage

No one from the manufacturers tells them that the "more storage" - multiplicatively more - lasts exponentially less.

For the same price, would you rather have a 1TB drive that will retain data for 10 years after having written 100PB, or a 4TB one that will only hold that data for 3 months after having written 2PB?

That requires support software they may not want to build

The software is already there if you know where to look.

and support requests from users complaining that toggling SLC mode lost all the data or toggling QLC mode back on did similarly

Do they also get support requests from users complaining that they lost all data after reformatting the drive?

It’s a valid business decision to not support that kind of product feature.

The only "valid business decision" is to make things that don't last as long, so recurring revenue is guaranteed.

Finally, the "smoking gun" of planned obsolescence: SLC flash requires nowhere near as much ECC and thus controller/firmware complexity as MLC/TLC/QLC. It is also naturally faster. The NRE costs of controllers supporting SLC flash is a fraction of those for >1 bit per cell flash. QLC in particular, according to one datasheet I could find, requires ECC that can handle a bit error rate of 1E-2. One in a hundred bits read will be incorrect in normal operation of a QLC storage device. That's how idiotic it is --- they're operating at the very limits of error correction, just so they can have a measly 4x capacity increase over SLC which is nearly perfect and needs very minimal ECC. All this energy and resource usage dedicated to making things more complex and shorter-lasting can't be considered anything other than planned obsolescence.

Contrast this with SmartMedia, the original NAND flash memory card format, rated for 100K-1M cycles, using ECC that only needs to correct at most 1 bit in 2048, and with such high endurance that it doesn't even need wear leveling.

Also consider that SLC drives should cost a little less than 4x the price of QLC ones of the same capacity, given the lower costs of developing controllers and firmware, and the same price of NAND die, yet those rare SLC drives which are sold cost much more --- they're trying to price them out of reach of most people, given how much better they actually are.

[vlovich123]

No you’re right. You’ve uncovered a massive conspiracy where they’re out to get you.

> No one from the manufacturers tells them that the "more storage" - multiplicatively more - lasts exponentially less. For the same price, would you rather have a 1TB drive that will retain data for 10 years after having written 100PB, or a 4TB one that will only hold that data for 3 months after having written 2PB?

These numbers seem completely made up since these come with a 1 year warranty and such a product would be a money loser.

> Also consider that SLC drives should cost a little less than 4x the price of QLC ones of the same capacity, given the lower costs of developing controllers and firmware, and the same price of NAND die, yet those rare SLC drives which are sold cost much more --- they're trying to price them out of reach of most people, given how much better they actually are.

You have demonstrated a fundamental lack of understanding in economics. When there’s less supply (ie these products aren’t getting made), things cost more. You are arguing that it’s because these products are secretly too good whereas the simpler explanation is just that the demand isn’t there.

[userbinator]

When there’s less supply (ie these products aren’t getting made), things cost more.

SLC and QLC is literally the same silicon these days, just controlled by an option in the firmware; the former doesn't even need the more complex sense and program/erase circuitry of the latter, and yields of die which can function acceptably in TLC or QLC mode are lower. If anything, SLC can be made from reject or worn MLC/TLC/QLC, something that AFAIK only the Chinese are attempting. Yet virgin SLC die are priced many times more, and drives using them nearly impossible to find.

such a product would be a money loser.

You just admitted it yourself - they don't want to make products that last too long, despite them actually costing less.

Intel's Optane is also worth mentioning as another "too good" technology.

[vlovich123]

I think you’re casually dismissing the business costs associated with maintaining a SKU and assuming manufacturing cost is the only thing that drives the final cost which isn't strictly true. The lower volumes specifically are why costs are higher regardless of it “just” being a firmware difference.