Subject: Re: chmod +x

From: Bob Proulx <[email-masked]>
Date: Mon, 6 Feb 2012 13:33:57 -0700

Francky Leyn wrote:
> Dear Bob, 
> 
> thanks for your intervention. 
> The problem is a lot clearer to me right now. 
> 
> It is indead a Virtual Box on top of Windows 7 with an NTFS system 
> and the Linux virtual box is Ubuntu 11.04. 

NTFS doesn't have any concept of the same file modes as a Unix-like
filesystem.  Therefore any adaption layer sitting between an NTFS
layer and a Unix filesystem layer can only make compromises.  It can't
do what it can't do.  For example, where would it store this
information?  What would NTFS do with it?

> My conclusion is the following: if I want to execute chmod +x properly, 
> I need an ext (4?) partition on my machine, separated from the Windows 7 
> NTFS system. Correct? 

Yes.  It doesn't need to be ext2, ext3, ext4.  It could be any POSIX
compliant filesystem.  That would include xfs, jfs, for example along
with many others.

If the files are stored on NTFS then NTFS can't do it.  If you want
Unix filesystem semantics then it must be on a unix filessystem.  For
example on the VirtualBox filesystem.  If you chmod files in /tmp in
the virtual machine everything works fine because that is using a real
unix filesystem.

I am sure that you thought that disk space was disk space and that you
would store files on the host NTFS and reach into them using a fuse
mount layer from the virtual machine.  That works up to a point.  The
data in the file is the same data in the file.  But you wanted to
chmod the permission bits and those are not understood by NTFS.

Bob