Are there any data remanence issues with flash storage devices?

I am under the impression that, unlike magnetic storage, once data has been deleted from a flash drive it is gone for good but I'm looking to confirm this.

This is actually relating to my smart phone, not my computer, but I figured it would be the same for any flash type memory. Basically, I have done a "Factory Reset" on the phone, which wipes the Flash ROM clean but I'm wondering is it really clean or is the next person that has my phone, if they are savvy enough going to be able to get all my passwords and what not?

And yes, I am wearing my tinfoil hat so the CIA satellites can't read my thoughts, so I'm covered there.

Solution 1:

Yes. Their behavior is identical. Essentially is the same thing.

Files aren't physically sorted in the way you "see" them: files are not located "inside" folders. In fact the're all around the drive. Then you have a folders and that folder is a file which list the locations of the files "inside the folder". When you delete a file, it's deleted from it's location in that file, physically the file remains stored.

Think in a book: the index says where the page is located. If you remove an entry from the index page that chapter doesn't get removed from the book.

So, data deleted can be recovered.

In another hand you're almost right: after deleting a file stored in a traditional magnetic storage it can be recovered at least it's overwritten. After several write passes it can't be recovered. Think in a notebook: when you write the pen prints the shape to the sheet below, and the another below that, etc. That's a traditional magnetic storage. Your question refers to flash memory which doesn't work so. After one pass overwritten there's no data recoverable; so if you delete and overwrite the entire disk you won't need seven passes to secure it.

Now getting more complex: since flash memory are limited in the number of writes they have algorithms to avoid overwrite a once and again over the same piece. They write where have less writes accumulated.

Final and simple recommendation: Format the device then get it full loaded with mp3 or video, then format again. zero index available after that.