Re: [Linux-NTFS-Dev] Windows Dynamic Disks, Parted

[Anton Altaparmakov]

On Sun, 5 Sep 2004, Andrew Clausen wrote:

> Hi Szaka,
> 
> On Sat, Sep 04, 2004 at 12:50:22PM +0200, Szakacsits Szabolcs wrote:
> > > If Parted sees that a partition table is a LDM disk (i.e. has a
> > > partition of type 0x42), should it simply refuse to recognize it?  i.e.
> > > say that it isn't a partition table.
> > 
> > Well, in the above email I wrote,
> > 
> >   "Partitioners must detect if one has a dynamic disk (it was designed to
> >   be very easy to detect) and refuse to progress or implement dynamic disk
> >   resizing."
> > 
> > But I've meant it in its context, namely non-destructive NTFS resizing.
> > 
> > General support is much more complex. You also have to think about cases
> > like:
> > 
> >     - user wants to get rid of windows dynamic partitions
> > 
> >     - user wants to fix spoiled windows dynamic partition entries
> 
> Can you give a practical example of this?

Made up example:  "I just ran fdisk in Linux and now Windows doesn't 
boot.  Help."

> >     - user wants to edit non-dynamic disk partition entries (I've thought
> >       it was impossible mixing windows dynamic partitons and basic 
> >       partitons but I've seen them working together)

Yes, this is possible.  I have seen it in action.

> >     - perhaps other scenarios
> 
> Shouldn't all of this stuff be provided by a Windows Dynamic Disk program
> rather than Parted?  Therefore, shouldn't Parted always refuse to touch
> it?

Perhaps.  OTOH parted could become such a program.  There is no LDM editor 
under Linux yet (mostly due to lack of requests for it).

> The counter-argument is that the Windows Dynamic Disk program might
> want to use libparted to handle the partition table stuff.  Is this
> likely?  This is rather hypothetical though, since the linux-ntfs
> projects' LDM program is still rather immature (is that right?).

Well it only does "fdisk -l" equivalent for LDM and does no editing.  But 
it is fully stable doing that.  (-:

> In any case, I don't have access to Windows XP Professional, and I
> can't test this stuff out myself.  I am comfortable with doing the
> following things immediately:
> 
>  * option 1: simply refuse to touch them.
> 
>  * option 2: make a new partition table type called dynamic-disk,
>  and make it read-only.  (It would share the disk_dos.c code).
>  
>  * option 3: make a new partition table type called dynamic-disk,
>  and make it only permit modification of non-0x42 partitions.

This is probably the best one.  Perhaps add a further restriction:  Do not 
allow to add partitions to a dynamic disk.  They would conflict with the 
LDM anyways...

Best regards,

        Anton
-- 
Anton Altaparmakov <aia21 at cam.ac.uk> (replace at with @)
Unix Support, Computing Service, University of Cambridge, CB2 3QH, UK
Linux NTFS maintainer / IRC: #ntfs on irc.freenode.net
WWW: http://linux-ntfs.sf.net/ & http://www-stu.christs.cam.ac.uk/~aia21/