Hi, Mick. On Sun, Jul 03, 2011 at 01:17:33PM +0100, Mick wrote: > On Sunday 03 Jul 2011 11:31:14 Alan Mackenzie wrote: > > Hi, Gentoo.
> > There's been a cock and bull story on comp.os.linux.setup and I'm > > wondering about some of the details. Mainly, I'd like some education, > > please! > > The story, in essence: > > (i) Windows XP is running, with a normal NTFS filesystem(s). > > (ii) Power off without a proper shutdown. > Not particularly wise on NTFS. Upon next boot up it'll try to run chkdsk, > which you *must* not interrupt. 99% of the time it'll happily continue into > a > normal boot. Not wise on any system. :-). > > (iii) Start again with a Linux Live CD (distribution not specified). > > (iv) This corrupts the NTFS journal(s). > No it does not. The NTFS journals (or the MSWindows partition and its NTFS) > have nothing to do with a LiveCD booting and running exclusively in RAM. I worked that out too. Beyond doubt, the teller of the tale was a troll, of dubious credibility. > > (v) It is now difficult to start Windows. > It would be without running chkdsk first, but you do not explain what the > difficulty amounts to ... error messages 'n all. The troll said he had to let chkdsk run "repeatedly", before W32 would boot. > > OK. My questions: > > o - Do live CDs actually mount filesystems on HDDs? > Only when you ask them to. I'm stupid. Of _course_ a live CD can't mount HDD filesystems at boot. To do this it would need /etc/fstab, for which it would need to be told the root partition. A live CD doesn't get this. > To mount NTFS you would these days use ntfs-3g: > ntfs-3g /dev/sda1 /mnt/windows > or > mount -t ntfs-3g /dev/sda1 /mnt/windows I hadn't heard of this. Useful to know, though. > > o - Would this actually try to mount an NTFS filesystem? > Linux LiveCDs will not typically mount anything whatsoever. They are by > default respectful of the devices on the system. I don't know if this > convention has changed recently, or if there are particular LiveCDs created > with different mounting conventions for the sake of MSWindows users - who > would not otherwise know how to mount a partition from Linux. > Can't recall what MSWindows based LiveCDs do (e.g. BartsPE). Something else I hadn't heard about before yesterday. > > o - Given that Linux's NTFS doesn't (?yet) do journaling (see kernel > > docs), would the driver not detect the presence of a journal and leave > > well alone? > The Kernel's NTFS driver is not safe for writing to a NTFS partition. It is > mostly a read only driver (check the Help page of the module, next time > you're > rolling up a new kernel). If you mount a NTFS partition using the kernel > driver and then try to write to it in a way that it requires a change to the > fs journals then you will invariably corrupt the NTFS fs. The working > solution for NTFS partitions these days is the ntfs-3g userspace application > as mentioned above. > CONCLUSION: > To recover a MSWindows partition which did not shutdown cleanly, boot into > MSWindows and let it run through the chkdsk sequence. When it finishes all > should be good. Yes. > If the MSWindows journal is corrupted, then you could try running > ntfsfix /dev/sda1 > to force it to run chkdsk next time it boots. > When the MSWindows OS boots next time it will go through the chkdsk routine. > If that does not fix it either, then the journalling problem is probably > unrecoverable. In that case ntfs-3g won't work. Instead you could try > mounting the partition using the Linux kernel driver (read only of course) > and > if it succeeds recover the files you need. > If the Linux kernel NTFS driver does not work, then we are into a full blown > recovery exercise. You could try testdisk and photorec. There are also a > bunch of MSWindows solutions too to recover NTFS partitions/files, but I'm > not > sure if any of these are open source. > HTH. Indeed it does. Thanks! > -- > Regards, > Mick -- Alan Mackenzie (Nuremberg, Germany).
