Most of the 80－100 $/TB disks use QLC which is painfully slow (slower than a spinning hard drive) when you outrun the SLC cache... Had to experience this during a drive migration with dd.

At least I never feel the need to do it, the closet I came to something like that was when I switched from a 240 GiB SSD to a 1 TiB one and just mirrored the old disk to the new one with dd, increased the partition and run a resize2fs. While that required ~30 Minutes it was a once in a decade thing for me.

While cacheless TLC gets parity with MLC at around 8 TB.

So, yes QLC flash needs really big drives to get enough of aggregate write performance.

Below that, there is not much rationale to use it evlconomically vs TLC.

On the other hand 2.5" HDD has been stuck at the same capacity for 2-3 years.

That's so cool.

There's also a need to keep shrinking the peripheral circuitry as the number of memory cells stacked above each mm^2 of buffers and charge pumps keeps growing.

3d nand manufacturing steps

It's a pretty clever arrangement, in this layman's opinion.

https://www.youtube.com/watch?v=PdS3jkDKmOU

Could these techniques be applied to logic circuitry too or is there something preventing that?

I guess its hard to etch all the different connections between gates if they're not uniform?

Is it possible for the same hardware to be QLC for some data, but then TLC, MLC or even SLC for other data on the same chip, perhaps to get faster write speeds or more write cycles for some of the data?

If so, it opens up a lot of optimization possibilities for strategies to maximize performance and lifespan

I don’t think you would intentionally ever use QLC as if it were TLC. Leaving it in QLC mode means you’re writing half the number of cells for whatever data you’re storing, which is going to be the best way to maximize drive lifespan.

Now storage class memory is something I am keeping an eye on. Can be a highly capable cache for storage as well as page file space for memory.

Lest anyone be led to believe it's a warp drive?

Reminds me of the alleged story about Xbox naming schemes. IIRC, Xbox was introduced when Playstation 2 was in stores. Then came the Playstation 3, but you can't sell an Xbox 2, since 2 is lower than 3 and thus must be worse, right? And Xbox 3 or 4 wouldn't make sense since there wasn't an Xbox 2.

So they named it Xbox 360 to bypass that problem.

But then what, Xbox 720? Xbox 361? Of course a new naming scheme had to be devised -> Xbox One. Then Xbox One X, and now Xbox Series X (and S).

Kinda funny how that seemingly small thing escalated to what seems like a series (ha) of workarounds to that initial problem.

Our whole company was hinged on a patent for a manufacturing technique to make either the source or drain leads a little more pointy so things could run faster and be more reliable with less power.