Re: [gentoo-user] Cannot edit files on usb flash drive.

[Alan McKinnon]

On Monday 08 March 2010 09:33:07 ubiquitous1980 wrote:
> Alan McKinnon wrote:
> > On Monday 08 March 2010 08:31:40 ubiquitous1980 wrote:
> >> I have a usb flash drive which will not allow me to edit its files.  I
> >> have tried chmod a+rwx -R $files but this does still not permit
> >> editing.  Further, the files within the directories refuse to have
> >> ownership changed via chown $myusername -R /mnt/disk.  Output is:
> >> operation not permitted.  Any ideas?  Thanks.
> >
> > This happens when the flash drive is type vfat. This excuse for a file
> > system does not have a concept of owners and permissions so the kernel
> > has to fudge it. You are finding that you cannot change these for the
> > simple reason that they do not exist and the kernel is pretending they
> > are owned by root with MODE 755 or some such.
> >
> > If hal is mounting the device, check your hal config, looking for some
> > likely named option.
>
> What config file would this be?  Can I find it in the handbook?

Hmmm, hal config files. Those things are deliberately obfuscated, I have no 
idea. You will have to search through /etc/

> > If the device is mounted via /etc/fstab, adjust the
> > uid/gid/umask/dmask/fmask options to mount in column 4. Full details in
> > the man page, under section "fat"
>
> I need to interact with university computers from time to time, any
> other file system with proper permissions, to be used under both linux
> and windows (without additional drivers)?

All windows file systems have this problem when accessed from Unix.

The permission models do not map to each other, so there is no translation you 
can do. The only effective route is to ignore the filesystem's 
owner/permission model and use some global value in it's place.


-- 
alan dot mckinnon at gmail dot com