kingcake wrote on 2024-03-04, 18:27:I was responding to the guy that said his SSD needed to be refreshed every week.
It makes sense to state who you are specifically responding to, otherwise you risk making stupid general statements. I just searched whole thread for a word "week" and you are the only one using it here.
kingcake wrote on 2024-03-04, 18:27:I was responding to the guy that said his SSD needed to be refreshed every week.
Of course nand needs to be refreshed now and then. I didn't say it never needs to be refreshed.
No offense, but is English not your native language? You seem to follow me around misunderstanding my posts.
Are you referring to me? I'd invite you to read the conversation carefully, including the posted links, because you've probably skimmed the tail, misunderstood the whole thing and jumped to conclusions.
I think what others have posted regarding TLC, QLC and newer Flash technology versus older SLC ones was that instead of storing just a single bit per cell, they store multiple bits per cell, which behind the scenes means reading multiple voltage levels.
Again, what I understood from the links that others posted, followed by my own investigation, it seems that this new technology is much less durable compared to the old one, so the signal degrades if it's not written very often. So in case of SLC, it was matter of years where the signal could degrade enough to become a problem, in newer technologies, where multiple voltage levels are stored per cell, this occurs much sooner, which can be as bad as in terms of days. A workaround from manufacturers is to let firmware move your data around periodically between the cells, which alleviates the problem somewhat at the expense of write cycles, and error correction mechanisms, so a data that is partially corrupted can still be read - this would explain slower reads when trying to access data that has been written long time ago.
In other words, it is not enough to just power on your SSD to retain the data, you have to re-write it periodically. For older SLC and even MLC-based SSDs, the period can be quite long, but for newer TLC/QLC+ SSDs this period becomes very short, enough to feel the effects in terms of days or weeks. This doesn't mean that in few weeks you lose your data, but the effect can be that reading the data that wasn't changed for quite some time becomes very slow. But, eventually, if you don't re-write your data, it'll get lost. I believe similar situation happens with recent (2014+) CF cards as well, which are unlikely to use old SLC technology.