Re: [Surprise-dev] GNU Parted and Partition Surprise

[Jan Kratochvil]

On Mon, Jul 23, 2001 at 11:10:29AM +1000, Andrew Clausen wrote:
> On Mon, Jul 23, 2001 at 02:16:01AM +0200, Jan Kratochvil wrote:
> > On Mon, Jul 23, 2001 at 09:54:45AM +1000, Andrew Clausen wrote:
> > ...
> > > And you want to swap the order.  You need to do something like:
> > > 
> > >   AAAAaaBBBBbb
> > >   AAAA  BBBBbb
> > >   AAAABBBB
> >             ^^^^=fatal requirement!
> 
> Huh?
> 
> > >       BBBBAAAA
> >     ^^^^=fatal requirement!
> 
> ?

This is just illustration for my provided sentence:
        otherwise you would need "min(|A|,|B|)" of free space

Without "md" you have a problem exchanging A and B.

1) Either you need enough free space to be able to copy the smaller of A or B to
   the free space (and remove it from its original place).

2) Or you need to split A to A1 and A2 and move the parts of A1 to A2:

AAAA  BBBB
AAAABBBB  
A1A1BBBBA2
A1  BBBBA2
A1BBBB  A2
A1BBBBA2A2
  BBBBA2A2
  BBBBAAAA
BBBB  AAAA

Without "md" you would have to move only parts of A1 to A2 in a step (for
example only a part of some big file).

3) Or "md" device.

...
> > > So, you can't just commit to the final state immediately...
> > > if you commit B to it's final state, it will clobber A.
> > 
> > Oh, sorry, OK, I got it now . So you need "md" device to rejoin and
> > 'virtualize' the space (otherwise you would need "min(|A|,|B|)" of free 
> > space).
> > Such virtualization is done by our/Tom's General Converter. If you want it 
> > by
> > kernel, use kernel features ("md")...
> 
> Oh, I see.  Right.  Interesting... never thought of that, very clever :)

More insane perversity than clever solution, I think... I will be trembling
during the night whether this discussion were just jokes what it is also
possible or whether you've meant it in real, eh.


                                                        Lace