Re: fdisk geometry

[Davidlohr Bueso <dave@gnu.org>]

On Thu, 2012-07-26 at 11:57 +0200, Karel Zak wrote:
> On Thu, Jul 26, 2012 at 11:29:40AM +0200, Davidlohr Bueso wrote:
> > > (a) where fdisk gets the information about the geometry from in  this 
> > > specific case?
> > 
> > fdisk gets the information from (i) user input, (ii) what the
> > kernel/bios thinks the geometry is, with the HDIO_GETGEO ioctl and (iii)
> > by inferring it from the partition table geometry.
> 
>  BTW, does it make any sense to read the geometry from partition table
>  if the partition table has been aligned according to the device topology
>  (for example 1MiB offset and grain)?

Hmm not really, no. In any case we got rid of the pt geometry,
__discover_system_geometry() only gets the info from the kernel.

> > > fdisk even bother displaying a geometry any more ? Doesn't it just serve 
> > > to confuse?
> 
>  IMHO for non-DOS compatible mode it would be better to ignore PT
>  geometry (read only info from kernel to have "some" values) and
>  don't display geometry in the default output, because it's completely
>  irrelevant.
> 
>  The same we can do with -S -C -H options -- it would be better to
>  print a warning if the options are specified for non-DOS mode.
> 

I agree.

>  I still see on many places suggestions like "use -S -H to align your
>  flash disk" or so... all this is legacy.
> 
>     Karel
>