NTFS & cygwin inodes

Corinna Vinschen corinna-cygwin@cygwin.com
Sat Jun 11 16:40:00 GMT 2005

On Jun 11 14:37, Lapo Luchini wrote:
> I want to produce an ISO image with mkisofs that contains LOTS of
> duplicated files.
> Unfortunately the "man" seems to state that option -cache-inodes is not
> usable on Cygwin (?_?)
> -no-cache-inodes
>       Do  not  cache  inode and device numbers.  This option is needed
>       whenever a filesystem does not have unique inode numbers. It  is
>       the  default  on Cygwin.  As the Microsoft operating system that
>       runs below Cygwin is not  POSIX  compliant,  it  does  not  have
>       unique  inode numbers.  Cygwin creates fake inode numbers from a
>       hash algorithm that is not 100% correct.  If mkisofs would cache
>       inodes on Cygwin, it would believe that some files are identical
>       although they are not. The result in this case  are  files  that
>       contain  the  wrong content if a significant amount of different
>       files (> ~5000) is in inside the tree that is  to  be  archived.
>       This  does not happen when the -no-cache-inodes is used, but the
>       disadvantage is that mkisofs cannot detect hardlinks anymore and
>       the resulting CD image may be larger than expected.
> Do they maybe just put is as a warning when the file system used is FAT?
> Is the problem there also for NTFS?

Good question.  It shouldn't, but I wouldn't give any gurantee.
However, mkisofs doesn't know the type of the underlying FS, so
it just plays safe.  The hash algorithm isn't 100% correct?  Well...
I'm wondering how they mean it and why.  Any hint would be nice.


Corinna Vinschen                  Please, send mails regarding Cygwin to
Cygwin Project Co-Leader          mailto:cygwin@cygwin.com
Red Hat, Inc.

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