Re: Making a vfat partition writeable by all in `users' group?

["D. D. Brierton" <darren@xxxxxxxxxxx>]

On Tue, 2003-04-22 at 15:37, Michael Schwendt wrote:
> It is a _mask_, hence it's name. Think of "umask" as a bitmask of
> the permission bits you want to _erase_.

Ah! Okay, I understand now.

> It is the same as the "umask" that is applied when you use "chmod",
> a boolean operation
> 
>   file_permissions = (NOT umask) AND chmod_value  
> 
> where "chmod_value" is either the value you specify upon changing
> the permissions of a file or the value that is stored for the file.
> 
> The FAT filesystems do not have as many permission bits as the
> ext2/ext3 filesystems. Upon mounting a VFAT partition, a compatible
> permissions value is constructed from the few FAT permissions bits
> and all bits specified in your umask value are erased. For the
> most files, the constructed default value is 0777 (rwxrwxrwx),
> so an umask=0007 masks "world/other" bits and the result becomes
> 0770.   [ (NOT 0007) AND 0777 = 0770 AND 0777 = 0770 ]

Thank you. Excellent explanation!

> I haven't tried dmask/fmask yet. The manual says they work with a
> 2.5.x kernel. But they look useful. 

Yep, I noticed that fmask and dmask only work for 2.5.x when I looked at
the man page again after reading your first reply.

Thanks!

Best, Darren

-- 
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D. D. Brierton            darren@xxxxxxxxxxx          www.dzr-web.com
       Trying is the first step towards failure (Homer Simpson)
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