As I explained in your other thread, it's not needed. One pass is enough.just performed the 35pass on my old macbook before thinking of selling and out of curiosity looked at my new MBP settings and noticed it only has 1, 3 or 7. Does this seems right? Why would they not give you the gutmann 35 pass erase as before? How can I get the 35?
I see two errors:just performed the 35pass on my old macbook before thinking of selling and out of curiosity looked at my new MBP settings and noticed it only has 1, 3 or 7. Does this seems right? Why would they not give you the gutmann 35 pass erase as before? How can I get the 35?
NIST said:Guidelines for Media Sanitization
"Advancing technology has created a situation that has altered previously held best practices
regarding magnetic disk type storage media. Basically the change in track density and the
related changes in the storage medium have created a situation where the acts of clearing and
purging the media have converged. That is, for ATA disk drives manufactured after 2001
(over 15 GB) clearing by overwriting the media once is adequate to protect the media from
both keyboard and laboratory attack."
Peter Gutmann said:In the time since this paper was published, some people have treated the 35-pass overwrite technique described in it more as a kind of voodoo incantation to banish evil spirits than the result of a technical analysis of drive encoding techniques. As a result, they advocate applying the voodoo to PRML and EPRML drives even though it will have no more effect than a simple scrubbing with random data. In fact performing the full 35-pass overwrite is pointless for any drive since it targets a blend of scenarios involving all types of (normally-used) encoding technology, which covers everything back to 30+-year-old MFM methods (if you don't understand that statement, re-read the paper). If you're using a drive which uses encoding technology X, you only need to perform the passes specific to X, and you never need to perform all 35 passes. For any modern PRML/EPRML drive, a few passes of random scrubbing is the best you can do. As the paper says, "A good scrubbing with random data will do about as well as can be expected". This was true in 1996, and is still true now.
You can use encrypted disk images, if you do not need the full disk encryption.And I use disk encryption in case a drive fails and I can't erase it.