Is it possible to PERMANENTLY delete data from compact flash?

[lasergecko]

Is it possible to PERMANENTLY delete the files FOREVER from compact flash. (Assuming this is possible).

 

[daniel1113]

Sure... just destroy the card. A gas fire, hammer, or any destructive force should do the trick.

 

[andyman7]

or write all zeros to the drive

 

[lasergecko]

Let me clarify, erase all the data permanently but still reuse the card. Is this even possible with Compact flash? Or it is like hard drives where need to go to extreme measures to erase it?

 

[NickE]

Depends on how secure the deletion needs to be - if it's simply a case of not being able to undelete some files, then a simple overwrite will do the trick, as Andyman suggested. On a large CF card, if you don't mind subsequent files being recoverable, then create a large blank image file in Photoshop or similar, sized to give the filesize you need and save it as uncompressed TIFF (JPEG is no good as the file will shrink significantly), then save that file onto the CF card. Delete the TIFF and you're done.

 

[Peter]

FlashROM chips, when erased, contain binary "1" all over. Similarly, writing new data over the entire capacity wipes out old data 100 percent.

 

[glugglug]

you can do a full format on the card. Even format it as NTFS if you like although your camera probably won't read it if it isn't FAT.

 

[AbsolutDealage]

Originally posted by: NickE
Depends on how secure the deletion needs to be - if it's simply a case of not being able to undelete some files, then a simple overwrite will do the trick, as Andyman suggested. On a large CF card, if you don't mind subsequent files being recoverable, then create a large blank image file in Photoshop or similar, sized to give the filesize you need and save it as uncompressed TIFF (JPEG is no good as the file will shrink significantly), then save that file onto the CF card. Delete the TIFF and you're done.

Just make sure that the image file is the same size as your CF card so that you can be sure you overwrite all the data (the file system used on the card encourages "even wear", so you never can be completely sure where your data actually lies). I'm sure if you overwrite the whole card, nothing short of a government forensic CF analyzer will be able to recover that data.

 

[Mday]

peter is correct. the floating gate of flash media pretty much means a bit is either 0 or 1. it's not at all like magnetic media which may still contain layers of old data. and you shouldn't ZERO flash media like people do to hard drives. electron tunneling limits the lifespan of flash media, and zeroing a one kills it faster.

 

[zephyrprime]

But you would have to zero it at least once or the data will still be extractable.

 

[MadAd]

Originally posted by: Mday
and you shouldn't ZERO flash media like people do to hard drives. electron tunneling limits the lifespan of flash media, and zeroing a one kills it faster.

If I had a flash card with data on it (a mixture of 0s and 1s) and stored it for some long time, would that mean the bits with the zeros would die first?


Also, what would happen if the flash card developed a bad cell like this? Would it be treated as a bad sector or would it corrupt the whole card preventing any data recovery at all?

 

[Mday]

Originally posted by: MadAd

Originally posted by: Mday
and you shouldn't ZERO flash media like people do to hard drives. electron tunneling limits the lifespan of flash media, and zeroing a one kills it faster.

If I had a flash card with data on it (a mixture of 0s and 1s) and stored it for some long time, would that mean the bits with the zeros would die first?


Also, what would happen if the flash card developed a bad cell like this? Would it be treated as a bad sector or would it corrupt the whole card preventing any data recovery at all?

the first one is an interesting question. i cannot answer it at all, i would not know where to begin the investigation as to which bit would be first to lose its "identity". of course, this assumes that one bit is statistically more likely to be lost than another while in storage. this assumption i would not readily make without seeing any evidence.

the writable lifetime of the early flash media was 1000 rewrites. this number has been extended to a million rewrites with the latest numbers for some families of flash (circuit design, not actual interface). a bad cell would be treated as a bad sector much like HDDs. dont worry though, formatting of storage in solid state media are such as to minimize the effects of electron tunnelling.

 

[Mday]

Originally posted by: zephyrprime
But you would have to zero it at least once or the data will still be extractable.

that is not true. once a bit is overwritten in solid state media, it's previous state is gone.

 

[Texun]

The above methods would work fine, but if you are really serious and don't want to lay awake at night wondering if it really is gone for good then destroy the card and get another. I'm not trying to be a smart azz, but your post suggests that you are looking for unquestionable confirmation that any information will be gone for good never to return under any circumstances, which I can understand. Depending on the cost and your ability to replace the card you could ditch it and rest easy.

 

[Mingon]

Easiest way is to buy an old digital camera, you cant retrieve data from a formated card in old camera's, Ive tried :-(

 

[dxkj]

Originally posted by: andyman7
or write all zeros to the drive

 

[dxkj]

Originally posted by: andyman7
or write all zeros to the drive

 

[NeoPTLD]

I think maximum security disposal standard for the DOD calls for physical destruction of all solid state and magnetic devices containing sensitive data.

 

[Mday]

Originally posted by: dxkj

Originally posted by: andyman7
or write all zeros to the drive

NO

you ones flash media, not zero!!! stop not reading the thread.