On Sun, 28 Nov 2010 18:48:18 +0100, Axel Freyn wrote: > Hi Camaleón, >> > But that is extremly dangerous...: you risk to loose/destroy >> > informations on the damaged filesystem (nobody guarantees, that >> > scandisk is not destroying data...). And especially defrag: this WILL >> > destroy data, which are in lost files (=sectors of the harddisk which >> > seem to be free according to the file system...). >> >> (...) >> >> I've never heard neither seen that before and have worked with ntfs >> volumes during many years. In fact, I've managed to "restore to live" >> windows systems that were unable to boot up by following that procedure >> (even an unexpected shutdown can make the OS to be unbootable -system >> files tend to become easily corrupted- and checking the file system >> structure solves the issue). >> >> Scan disk (chkdsk) and defrag are the standard and recommended tools >> for dealing with MS file systems problems. Maybe they cannot solve the >> problem but won't aggravate it either. And before "wiping out" the hard >> disk, I think it is at least worth a try.
> The point I wanted to make is the following: Defrag shifts parts of the > files -- and in order to do so, it OVERWRITES unused parts of the disk. > Now: as soon as the filesystem is corrupted, one can't trust anymore in > the information which parts are "unused" -- so it can happen that defrag > (or any other tool which writs on the disk) overwrites > file-informations, which belong to a "lost" file, but which are believed > to be "free" and "unused" by the filesystem. In my opinion, this danger > is not limited to ntfs, but exists in every filesystem: as soon as the > filesystem is corrupted, one can't guarantee that the blocks marked as > "free" don't contain usefull information -- and that's why I wouldn't > write anything on the partition! > > A similiar point is true for scandisk / chkdsk: Again, independent on > the filesystem: Once the filesystem is corrupted, the recovery tool has > to make assumptions about what is the "correct" information -- and if it > makes the wrong assumption, it WILL destroy data. For example: How can > chkdsk guarantee that, whenever it writes some information on the disk, > it uses a truely "free" part of the disc? maybe on this place was a > piece of an important file, which was lost by the file-system > corruption? Well, no need to worry. You are thinking in the worst scenario but even if the file system structure is completey destroyed, "defrag" is also capable of performing a test only disk analysis and so does "chkdsk". > Of course the question is, how important the data are -- is it worth the > effort to first create a copy of the partition and then to work on the > copy? A backup copy is always desiderable. In fact, there should already exist a copy with the latest backup... of a "week" ago and not from a "year" ago >:-) Greetings, -- Camaleón -- To UNSUBSCRIBE, email to debian-user-requ...@lists.debian.org with a subject of "unsubscribe". Trouble? Contact listmas...@lists.debian.org Archive: http://lists.debian.org/pan.2010.11.28.18.19...@gmail.com
