On Sunday, August 29, 2010 09:16:28 Bruno Wolff III wrote: > On Sun, Aug 29, 2010 at 07:46:49 +0100, > Marko Vojinovic <vvmarko@xxxxxxxxx> wrote: > > Starting from the premise that every hard disk has in principle limited > > capacity to store data, one can always fill it up completely, then > > rewrite it completely again. I see no way of the old data being > > recoverable, because this is in contradiction with the fact that the > > disk was filled up completely two times. The old data has to be > > destroyed in order to make room for new data. At least as far as I can > > understand it. > > At least at one time it was possible because the data is stored in a region > and when overwriting the region you don't hit the same spot every time. > With the right equipment you could see these areas and tell what data had > been written in that spot in the past. Yes, but given a certain number of rewrites of each region, the old data is bound to be rewritten sooner or later, right? In addition, if this overwriting is a random process in terms of a precise spot where data is written, you cannot hope to be able to recover *all* (or a high percentage of) old information. I guess that after 2 or 3 rewrites of the whole disk, the large portion of the original data gets completely overwritten, and only random bits of that data can be recovered, in amount that is too small to be useful for anything. I have an old Seagate 1.2 GB hard disk from 10 years ago, which is still operational on one of my machines at home. If we assume that over these 10 years I have rewritten it 1000 times, the total amount of data that passed through the disk is cca 1 TB. I simply don't believe anyone is able to recover whole 1 TB of data from this disk, no matter how big budget and equipment one may have. I don't even believe they could recover even 20% of that terabyte. So I still don't see how the original statement may hold. There just has to be a limit of how much information can be stored on a disk, and once you overflow this limit, old data is bound to get lost. Best, :-) Marko -- users mailing list users@xxxxxxxxxxxxxxxxxxxxxxx To unsubscribe or change subscription options: https://admin.fedoraproject.org/mailman/listinfo/users Guidelines: http://fedoraproject.org/wiki/Mailing_list_guidelines
