How about user configured SSD's? SLC, MLC, TLC... you choose.

[Hulk]

It would be nice if manufacturers could offer SSD's in which the user could select the mode of operation via firmware.

So if you purchase a 240GB MLC drive it could also be flashed to 120GB SLC or 480GB TLC. With dynamic cache options as well.

This way you might initially use the drive as 120GB SLC for a boot drive or heavy write use drive and later "retire" it to a TLC media storage drive.

I'm just thinking it would be a great way to allow the user to customize the drive.

Warranty and endurance would be a little complicated but I'm sure the drive could track various usage. Also specs would have to be listed for each operating mode but it seems doable and worthwhile.

What do you think? Good idea or ridiculous?

 

[Charlie98]

You make that choice when you select a SSD to buy. Seems like trying to control something as imbedded as how it handles data via FM would be a barrel of monkey nuts.

 

[ryderOCZ]

SLC, MLC, and TLC are different types of Nand, each with different physical properties, you can't "flash" one to another. This renders the idea impossible although the concept is intriguing.

 

[Emulex]

Well it would make it terribly difficult to manage without the operating system being aware of the type of nand presents and how to optimize for that setup!

Why not just buy multiple drive types and use them appropriately?

You can go to servethehome.com and find great deals on SLC and enterprise flash drive deals there!

 

[Hulk]

SLC, MLC, and TLC are different types of Nand, each with different physical properties, you can't "flash" one to another. This renders the idea impossible although the concept is intriguing.

How does Crucial with the MX200 series switch between SLC and MLC modes in those SSD's? From what I've read when less than 50% full those drives will operate in full SLC mode and then transition to SLC/MLC as the drive fills up.

 

[Hulk]

You make that choice when you select a SSD to buy. Seems like trying to control something as imbedded as how it handles data via FM would be a barrel of monkey nuts.

As I noted to another poster Crucial does it with the MX200. And others do it with SLC cache as well.

 

[hhhd1]

This way you might initially use the drive as 120GB SLC for a boot drive or heavy write use drive and later "retire" it to a TLC media storage drive.

The will not work, but the opposite might.

TLC are rated for 1000 cycles,
MLC for 3000,
SLC for 10k+ ?

so after passing the first 1000 cycles, the SSD is not going to usable as TLC anymore, and the only options are use it with half capacity as MLC, or 1/4 of the capacity as SLC.

after 3000 cycles, you must use it as SLC only.

so, if manufacturers did this, it would be to give you a TLC drive with allot of capacity, and as the drive ages, the space will decrease to 1/4, but while giving you a usable SSD.

Since not all NAND blocks will age at the exact same time, the firmware could convert TLC to MLC and then to SLC as they loose their quality, and decrease the size gradually.

 

[Hulk]

The will not work, but the opposite might.

TLC are rated for 1000 cycles,
MLC for 3000,
SLC for 10k+ ?

so after passing the first 1000 cycles, the SSD is not going to usable as TLC anymore, and the only options are use it with half capacity as MLC, or 1/4 of the capacity as SLC.

after 3000 cycles, you must use it as SLC only.

so, if manufacturers did this, it would be to give you a TLC drive with allot of capacity, and as the drive ages, the space will decrease to 1/4, but while giving you a usable SSD.

Since not all NAND blocks will age at the exact same time, the firmware could convert TLC to MLC and then to SLC as they loose their quality, and decrease the size gradually.

Did you read that information somewhere?

I have a feeling that when the NAND is operated in SLC mode the voltage applied to the cell is much lower than when the cell is used as TLC and this is most likely the primary reason that SLC cell have higher endurance than TLC or MLC. Also, since there is less overlapping of levels as you move from TLC to MLC to SLC I would think that the read is easier, ie more cut and dry to get an determinate voltage level to read the cell status.

So I don't believe that 3000 writes to TLC creates the same media wear as 3000 writes to a cell programmed to be SLC.

I'm thinking it's more complicated than simply "writes."

It's probably more like 30,000 SLC writes is equivilent to 6,000 MLC writes, which is equivalent to 1,000 TLC writes or something like that. Once that "formula" is derived for a particular process technology then the firmware could keep track of the "total wear" for each block.

Yes, it gets a little complicated but I still think it could be done. As I wrote Crucial is pretty much already doing it.

Possible or not this is interesting.

 

[hojnikb]

SLC, MLC, and TLC are different types of Nand, each with different physical properties, you can't "flash" one to another. This renders the idea impossible although the concept is intriguing.

Not really. TLC is just a way to differentiate the voltage states from nand cells. So in theorey you can make SLC flash act as an MLC.

But in practise, this is not possible due to MLC/TLC reqiring more advanced hardware DSP and ECC.

But it absolutly works the other way around; cell designed for TLC use can be "emulated" as MLC or SLC pretty easily. This is actually exploited in many drives (samsung evo line, mx200, ocz from vertex4 onwards...).

 

[hojnikb]

FYI this configuration is sorta possible with some flash drives.

Just look for MPtool for desired controller. Some can be actually set to use the whole space as "performance" portion (usually used to cheat benchmarks).

I actually made my 32GB TLC flash drive into a ~10GB performance monster (well, it capped the maximum controller speed).

 

[hhhd1]

Did you read that information somewhere?

Not really, just following news about SSDs, reading articles ..etc.

But from what I understand, the main difference between SLC and MLC and TLC are charge levels,
For SLC, the NAND cell has to either "have charge" or "have no charge", while with MLC, it needs to have 4 different levels of charge accurately, with TLC it needs 8.

So, the problem with TLC is that the NAND cells after only 1000 cycles start loosing the ability to hold accurate charges, while if you use the same cell for SLC, where accuracy of up to 8 levels is not needed, it might work fine.

 

[hojnikb]

Not really, just following news about SSDs, reading articles ..etc.

But from what I understand, the main difference between SLC and MLC and TLC are charge levels,
For SLC, the NAND cell has to either "have charge" or "have no charge", while with MLC, it needs to have 4 different levels of charge accurately, with TLC it needs 8.

So, the problem with TLC is that the NAND cells after only 1000 cycles start loosing the ability to hold accurate charges, while if you use the same cell for SLC, where accuracy of up to 8 levels is not needed, it might work fine.

It would sorta make sense to use "bad" cells for overprovisioning area first in MLC config and then in SLC config. This would most certanly extend the life of the SSD with no user intevention.

I believe sandisk is using a similar idea with their ultra ii