3 ms·
> Thumb stick, SSD, non-volatile memory in general - needs a plug-in once in a while. What do you mean by this? It is non-volatile after all.
by bmrp 7y ago
> Thumb stick, SSD, non-volatile memory in general - needs a plug-in once in a while.
What do you mean by this? It is non-volatile after all.
- adrian_b 7y agoAny non-volatile memory is characterized by a "retention time" after which it may loose the information stored in it. The retention time depends on the storage conditions, especially on temperature & humidity. For ancient flash memories, with large cells and 1 bit per cell, the retention time can be of 10 years or even 20 years. After that the capacitor will discharge, because the insulation is not perfect. For modern flash memories, with much smaller cells and wit 3 or even 4 bits per cell, the electrical charge variation that will lead to wrong bits is much less, so the retention time can vary from a few years for a new SSD stored at low temperature to a few months for a used SSD stored at a higher temperature. At a high enough temperature (not impossible to reach, e.g. when forgotten in sun light), the retention time can be reduced to days. When a SSD is used, i.e. it is powered, the microcontroller inside it rewrites its cells from time to time to avoid losing data. If you store it without using it, after the guaranteed retention time you may lose data. Consumer SSDs and memory sticks are guaranteed for a retention time of 1 year, so you should not expect more than that.
- bmrp 7y agoI did not know they had to maintain data that way, but I guess it makes sense. That is good to know! Thanks for the explanation! Now I know to never use an SSD as backup o.O