Completely clearing a flash card's memory.

Posted by: Tony Lockhart on 21 March 2006

Does anyone know how to do this so that ALL files are removed? I just ran some recovery software on my camera's CF card and there were images from last August. The card has been full at least once since then and has been reformatted several times.
I know it could be argued that it doesn't affect performance, but I'd rather have an empty card for Silverstone this month and know that it's a 'virgin'.

Thanks

Tony
Posted on: 21 March 2006 by Guido Fawkes
Card Wiper
Posted on: 21 March 2006 by count.d
Tony,

A card can never realistically be full. There will always be a few hundred/thousand bytes not used by the camera and so you will find the odd image appear from the past.

I don't see any advantage whatsoever in reformatting the card with another sofware, when your camera only has to do it again. I prefer to format cards only by the camera that will use it.
Posted on: 21 March 2006 by Stuart M
Then again if you want to give a flash card/drive to someone else then you may wan't to clear it.

When you delete a file you don't zap most of the data. Just remove the pointer to the file, to erase the data and prevent recovery you need to over write the data. Erase programs often just write over the card with random 0's or random numbers to remove traces.

One easy way and free way to destroy any sensitive info on a card (this will not work for a disk as forensic data retrieval can I believe go down to 10 or even 20 data rewrites) is to:-

  • Format the card
  • Take a large pic/file that your not bothered about and write it to the disk again and again (e.g. copy so it's pic1, pic2 etc) until it's full.
  • Then check the free space and fit in smaller files you don't care about again until it's full.
  • Format the card again


That should overwrite the majority of traces left unless your concerned about small fragments of data - If so buy an erase program.
Posted on: 21 March 2006 by Tony Lockhart
Thanks, all.
I must say that I was surprised to see over 200 'erased' images still on the card. Some were unusable, most were as good as new.

Thanks again,

Tony