[LinuxBIOS] USB floppy boot

[Baski]

I have a tiny kernel (not linux) and GRUB in a floppy disk. How can I make it to
boot using linuxbios?  The floppy already boots with the original bios.
I also have a USB floppy drive.
TIA - Baski

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[Peter Stuge]

Hello,

On Sun, Dec 09, 2007 at 12:26:21AM -0800, Baski wrote:
> I have a tiny kernel (not linux) and GRUB in a floppy disk. How can
> I make it to boot using linuxbios?

A few things need to be considered:

* How does the kernel try to find the system information that is
  usually exported by the BIOS in quite old-fashioned ways?
  At a minimum, the kernel needs to know how much memory is in the
  system. LB does not offer the same methods as a BIOS to learn this.

* Does the kernel use other BIOS interrupt services? LB does not
  offer any.

* How large is your kernel?
  If it can fit with LB in the boot flash (which is between 256kb and
  1MB) you don't need the floppy at all.

* Is the floppy a requirement?
  Currently no other payload than a full kernel (Linux or other) with
  it's own floppy drivers can read from the floppy drive.

//Peter

[Myles Watson]

> On Sun, Dec 09, 2007 at 12:26:21AM -0800, Baski wrote:
> > I have a tiny kernel (not linux) and GRUB in a floppy disk. How can
> > I make it to boot using linuxbios?
>
> A few things need to be considered:
> How does the kernel try to find the system information that is
> usually exported by the BIOS in quite old-fashioned ways?
> At a minimum, the kernel needs to know how much memory is in the
> system. LB does not offer the same methods as a BIOS to learn this.
> Does the kernel use other BIOS interrupt services? LB does not
> offer any.

You could try ADLO (The Bochs emulator's BIOS as a LinuxBIOS payload) to
supply these services.  The most recent BIOS from Bochs (not the one in the
LinuxBIOS tree) has some timing fixes that allow it to work in real
hardware.

Myles