Booting with an "extended" floppy

[Thierry Laronde]

Hello,

As I am completing the french grub-howto, I have had the idea to put some
"questions" --- i.e. exercices --- just in order to help everyone
understanding some principles about booting.

BTW, I have the idea of the following question, but I'm still looking for 
the answer.

There is a part of a floppy that is lost because
of the formatting informations. Roughly, the "real" size of the media is
2MB. Thus, if we are able to make it bootable, to have a bootloader
installable on it and understanding blocklists, we can `dd' a stage1, a
stage2, a kernel and a root image for a ramdisk, and finally a 512octets
menu.lst giving the informations necessary to stage2 (in blocklists) in order 
to put everything up.

This, theoretically, allow to have a 700k kernel and 1MB root file system
compressed on the very same media.

But the problem is to allow the BIOS and GRUB to access all these
informations. Is it enough to find a way to tell it how many cylinders and
sectors it must expect from the floppy ? In the process of loading stage2,
are there some impossibilities to load the blocks if the floppy is not a
"standard" one ? Is it necessary, using `superformat' to create enough
"normal space" at the beginning of the floppy, in order to load stage2, then
to give some extra informations about the disk geometry to allow stage2 to
reach extra informations ?

Thanks for any tip,
-- 
Thierry LARONDE, Centre de Ressources Informatiques, Archamps - France
http://www.cri74.org
PingOO, serveur de com sur distribution GNU/Linux: http://www.pingoo.org