Recovering data from a chip (MicroSD)

  • #26
Tom.G
Science Advisor
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The paranoid approach (or CYA approach):

Windows does a write to the directory every time a file is accessed (read).

Well, DOS isn't quite as bad, mostly just risky from operators errors.

My detailed information on those SD chips is limited, but since they have Auto wear-levelling (and maybe re-allocation ?) algorithms built in, just powering them up may make them worse. On Hard Disk Drives it will almost always make them worse.

Treat them as you would a fire in your house; are you going to try to blow it out, grab a fire extinguisher, or call the fire department. Yeah, it depends on whether someone dropped a match on a concrete floor or there is an attic fire blocking access. With the SD card you don't know which you have.

If the data is important use the fire department option and apply some Recovery Software! First step is use the recovery software to make a copy if at all possible. Then work on the copy. Or if it's really important, make a copy of the copy and work on that second generation. Copying the original just could have been the last access you will ever get!

Well, enough scary stories. Take your pick.

Cheers,
Tom

p.s. Please keep us updated. Every data point we can get can help us all when the situation strikes us.
 
  • #27
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@Vanadium 50 I think @DaveC426913 was only trying to switch his command prompt to the letter for the misbehaving device; not actually trying to write anything to the device. I recommended against switching to the device, in particular because he reported that he gets a hang when tries that. Recovery methods in general don't try preliminarily to set a misbehaving device as the 'home drive'; they treat it as a foreign unknown until more is known.
 
  • #28
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@DaveC426913, I think that Clonezilla live might be a good option. If you are going to use that, please DO NOT DISREGARD ANY WARNINGS. The warnings appear in pink boxes and-or red lettering there, so they're conspicuous enough that they should not easily go unnoticed by a person who is reading the instructions.

The image file that you get from running Clonezilla live is not something that is suitable for you to mount or to browse directly. The contemplated method is that after you have made the image file, you restore it to another device, and then go after the files that you want as they may appear on the other device. That's along the lines of the conservative approach that @Tom.G suggested.

Given that you are able to plug the SD card directly in, please let us know what happens when you do not try to navigate to the device and set its top level as the home directory, but instead, from a command prompt, please try using: ##\mathtt {\text {dir E: /s } }##
 
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  • #29
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You could close the card but I would not overly worry if you cannot, you will have to be unlucky to lose more data because of it. This is more relevant if you want to recover a deleted file from an accessible drive as you do not want the actual data overwritten by writing new data to it which you cannot do in its present state. Physical spinning disks aswell as SSD's will detect any physically bad sectors and will move the data around to knwo good sectors, potentially overwritting any data you wish to recover, this is why you have been asked to clone the disk. As far as I am aware I am unsure that SD cards have this functionality.

Put it into a PC card reader and use dedicated recovery software on the PC to read the contents. All storage is like a book, aswell as the data stopred on it there is an index which states where the data is actually held on that disk. When you open a file on your computer it does not read the whole drive looking for it, it looks at the index to tell it where the data is. If that index is corrupt, then you will not be able to read and it will appear corrupt. Using dedicated recovery software, that software will read the entire disk for data, in effect creating it's own index in the process. From there it will tell you what files it has discovered and which can be recovered.
 
  • #30
There is a product called Disk Drill. Also there are hardware devices which will clone a drive.
 
  • #31
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