LDPC and ECC Explanation

[gameboybin]

Hi everyone,

I recently just started out on Flash Recovery and heard a lot about LDPC and ECC

I have googled, and read through LDPC and ECC on google search. And have some description about those 2 things. However I still have very small understanding about them and what they do to the Monolith, Flash, and what do they do to Recovery in general.

I would love to understand more about the situation of SD, Micro SD, Flash situation right now.

And would love to learn more about LDPC and ECC that affects our Recovery Community. Will it be cracked in the future?? and how far are we to achieve that??

Would love to read some books, some posts, videos about them and about our situation right now of Flash Recovery?

Many Thanks!

[arvika]

Maybe start from BCH. It is implemented at all flash recovery tools and looks simpler than LDPC:
https://en.wikipedia.org/wiki/BCH_code

[ChristianMorris]

You can find some educational videos about them on YouTube.

[HaQue]

watch this thread.
https://forum.hddguru.com/viewtopic.php?f=13&t=43582

[ddrecovery]

Looks like you are just starting out so to put it in its simplest terms. Flash memory is in a constant state of degradation. The simple action of writing data to a cell degrades it. So ECC (Error Correction Code) is a way to reallocate the data in those bad cells/blocks to other areas. LDPC does a similar thing, but uses complex mathematical calculations to achieve it. No one has successfully reversed engineered LDPC algorithms yet. So any flash device that uses LDPC is generally not recoverable to chip-off/pinout methods. That may change in the future as technology develops.

[pepe]

to put it clear: ECC isn't relallocating anything, it is an applied redundancy in a way that the controller can find out where bit errors are in the read data so that it can flip these (correct the errors). LDPC is a way of ECC, just like BCH, Reed-Solomon and some others.
ECC stands for Error Correcting Code, the algorithm can vary, just as the error correcting capabilities of the code.

pepe

[ddrecovery]

to put it clear: ECC isn't relallocating anything, it is an applied redundancy in a way that the controller can find out where bit errors are in the read data so that it can flip these (correct the errors). LDPC is a way of ECC, just like BCH, Reed-Solomon and some others.

You are right, I was over simplifying for the OP.

ECC stands for Error Correcting Code. pepe

We do disagree on that, but its just semantics

[Rudra]

Which devices implement LDPC ?Where can I get more details of SSD microcontrollers there working etc. Currently I outsource my ssd work to a frind having pc3000 portable but nearly 90% cases are rejected for the reason mcu not supported
I am wondering how flash recovery guru's like arvika & others do these recoveries .
Besides ace portal where is more details of latest ssd manufactures and controllers they use etc.
Thank You

[HaQue]

>>Which devices implement LDPC ?
USB flash drives and SD cards for example. You likely won't know until you dump them.


>>Where can I get more details of SSD microcontrollers there working etc. Currently I outsource my ssd work to a frind having pc3000 portable but nearly 90% cases are rejected for the reason mcu not supported.

This is likely not due to LDPC only, but no-one has successfully done the reversing needed to support those SSD's. Info at a technical level? Not easy to come by.


>>I am wondering how flash recovery guru's like arvika & others do these recoveries .
They have built their knowledge up over many years of hard work and Many, Many successful and failed cases. They have studied their tools and all the available information, and done some true research on their own. of course there are a few other factors, but do not make the mistake of thinking these guys have it easy!


Besides ace portal where is more details of latest ssd manufactures and controllers they use etc.

It may be a better idea to identify what details you need, and then go after that. Vacuuming up info will not really help you.