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