Hi cgsecurity, community,
Thanks for testdisk - I helped recovering files with it and it has been fantastic.
I have a question and I'm not sure where is best to ask, I thought that someone here might know this.
Long question short: Low level format on a Canon S110 seems to write zeros everywhere in the card but it can't be done as fast as it does. What's happening?
And, anyway to restore this?
But basically, and I'm testing on a Linux machine with hexedit: after doing a "Low level format" everything seems to be zero (if it's not the "Low level format" I can see the previous files and I'm sure that they could be recovered). But the "Low level format" seems to erase everything faster than I would do with "dd if=/dev/zero of=/dev/... bs=10M": how is this being done?
And, obviously, any way to "undo" it? (dreaming of an "hdparm" to undo it )
Thank you very much!
What is "Low level format" and why is that fast?
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- Search for posts on the same topic before posting a new question.
- Give clear, specific information in the title of your post.
- Include as many details as you can, MOST POSTS WILL GET ONLY ONE OR TWO ANSWERS.
- Post a follow up with a "Thank you" or "This worked!"
- When you learn something, use that knowledge to HELP ANOTHER USER LATER.
Before posting, please read https://www.cgsecurity.org/testdisk.pdf
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Re: What is "Low level format" and why is that fast?
The camera is probably using a DISCARD or TRIM command: https://en.wikipedia.org/wiki/Trim_(computing) followed by a filesystem quick-format.
Some data recovery company can extract the memory chip and bypass the flash controller to recover the previous data.
Some data recovery company can extract the memory chip and bypass the flash controller to recover the previous data.
Re: What is "Low level format" and why is that fast?
I also found:
https://superuser.com/a/568054
It talks about:
ERASE_WR_BLK_START
ERASE_WR_BLK_END
Last night I did a bit of reading and I thought that the TRIM command was for SSD and the ERASE_WR_BLK_* are for SD cards (but, either way, same visible result from Linux for me without special electronics)
I guess that nothing that from a Linux computer without special electronics can be done.
Thanks very much!
https://superuser.com/a/568054
It talks about:
ERASE_WR_BLK_START
ERASE_WR_BLK_END
Last night I did a bit of reading and I thought that the TRIM command was for SSD and the ERASE_WR_BLK_* are for SD cards (but, either way, same visible result from Linux for me without special electronics)
I guess that nothing that from a Linux computer without special electronics can be done.
Thanks very much!