Bug#450951: grub can't get installed past 1TB

[Samuel Thibault]

Samuel Thibault, le Mon 12 Nov 2007 16:24:34 +0000, a écrit :
> This is because the HDIO_GETGEO ioctl is limited to 65535 cylinders
> (i.e. ~1TB), and for bigger values Linux just returns 65535.

Or not. Documentation/ioctl/hdio.txt says:

          Not particularly useful with modern disk drives, whose geometry
          is a polite fiction anyway.  Modern drives are addressed
          purely by sector number nowadays (lba addressing), and the
          drive geometry is an abstraction which is actually subject
          to change.  Currently (as of Nov 2004), the geometry values
          are the "bios" values -- presumably the values the drive had
          when Linux first booted.

          In addition, the cylinders field of the hd_geometry is an
          unsigned short, meaning that on most architectures, this
          ioctl will not return a meaningful value on drives with more
          than 65535 tracks.

          The start field is unsigned long, meaning that it will not
          contain a meaningful value for disks over 219 Gb in size.

I'd say that when lba is enabled (most probable with such disk anyway),
not check should be done at all on the geometry, notably 
      if (cylinder_offset >= geometry->cylinders)
              return BIOSDISK_ERROR_GEOMETRY;
in stage2/bios.c

Samuel