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    SubjectRe: Filesystem for mobile hard drive
    Le quartidi 24 pluviôse, an CCXIV, Phillip Susi a écrit :
    > Ahh yes, the per file limit. BTW, why are you saying "To" and "Go" when
    > you apparently mean "TB" and "GB"?

    I use the french word octet instead of byte, because it is less error prone
    (when you read "mb", does-it really mean megabit, or does it mean that the
    author is lazy about capitalization?) and a little bit more precise. Tough I
    actually am French, I did not start using a French word in English by
    myself. I copy a practice of the IETF: the RFCs use octet more than byte.

    > The fat data structures do not encourage fragmentation any more or less
    > than ext2/3. NTFS is slightly better, more comparable to reiserfs than
    > ext2/3, but the difference is small. What causes massive fragmentation
    > is how the driver chooses to allocate new blocks as you write to files.
    > Microsoft has always used about the worst possible algorithm for doing
    > this you can imagine, which is why fragmentation has always been a big
    > problem on their OSes. Linux is smarter and allocates blocks such that
    > fragmentation is kept to a minimum.

    I believe you about that.

    > I have not done any testing, but I know no reason why it would be worse
    > than fat.

    That is a very good point. If windows can read UDF on hard drives and not
    only DVD, UDF could probably supersede FAT completely.

    Thank you for pointing me that direction.

    > It does not do transaction logging, and there currently is no
    > fsck for it, so for safety reasons, it may not be such a good choice.

    I have a Solaris 9 near at hand, and I see a /lib/fs/udfs/fsck, and in the
    source tarball of OpenSolaris, I find a directory
    usr/src/cmd/fs.d/udfs/fsck/. It does not compile out of the box, but it may
    be possible to port it with limited effort.

    > I agree. I think the VFS layer should process the uid/gid options. By
    > default it should replace nobody with the specified id, and fat and ntfs
    > should just report all files as owned by nobody. Then a new option
    > should be added to force the translation for all ids, not just nobody.

    I agree with that (except maybe for the NTFS part, which I do not know; let
    us just say "UID-less filesystems"). Maybe a full UID translation system
    similar th the one in NFS could be useful, or a generic hook for modules,
    but having basic UID overriding would be great.

    Unfortunately, the VFS subsystem is something too complex for me at this
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      Last update: 2006-02-13 11:39    [W:0.021 / U:47.844 seconds]
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