Re: Floppy management?

[Rob Browning <osiris@cs.utexas.edu>]

Jean Orloff <orloff@lapp.in2p3.fr> writes:

> 1) How to prevent a user to prematurely eject a disk before sync is
> over?  Mounting with the sync option is not enough: that's the way I
> do it, and still the fd light goes off before the file is truly
> written to disk (and umount or sync gets it on again).

You can't.  If we had Mac style drives that had to be asked to eject
the disk, you could have some protection.  This falls under the
category of "just don't do that".  No choice, given the hardware.

BTW, there's a program out there somewhere called DevAlloc that might
interest you.  I think the model is that you can let a group of users
have the right to allocate some device for their exclusive use for
some period of time (I think it's partially done with chown).  So a
user could do something like:

  allocate /dev/floppy
  do stuff with the floppy if this succeeds
  deallocate /dev/floppy

I haven't actually looked at the program, so I can't say how it works,
or even how well.  I could imagine that something like this could be
extremely useful now that things like Zip drives (or even cdroms) are
really cheap.

I actually had to write a pair of scripts that let a group of users
(via sudo) exclusively mount and unmount a zip drive, and optionally
remap users and groups on the zip disk on mount (and remember and
unmap them on unmount) so that if you have different uids at home and
in the lab, you still get the same results both places.

(or perhaps there's some better mechanism we already have that I just
don't know about.)

--
Rob

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