On Wed, Jun 14, 2000, Jeff Garzik <jgarzik@mandrakesoft.com> wrote:
> "H. Peter Anvin" wrote:
> > Followup to: <200006141949.VAA09667@lrcsun15.epfl.ch>
> > By author: Werner Almesberger <almesber@lrc.epfl.ch>
>
> > > For space-constrained cases (e.g. embedded systems), the existing
> > > comparably lean interfaces between boot loader and kernel should of
> > > course be preserved.
>
> > There is a major -- I would say, fatal -- problem with that: the Linux
> > kernel doesn't allow access to the device drivers in the bootstrap ROM
> > (i.e. the BIOS.) This becomes particularly problematic if you want --
> > and I argue you *do* want -- the boot loader to assemble a
> > kernel/initrd to match your system hardware configuration.
> >
> > The obvious solution is to construct a boot loader such that it can
> > use Linux kernel filesystems. There are two ways to do this, and I am
> > yet to be certain which way is really the better.
> >
> > a) Built a boot loader with a VFS that is similar enough to the Linux
> > kernel internals that it is easy enough to port drivers.
> >
> > b) Strip down the Linux kernel so that it can run on top of the BIOS.
> > This means all interrupts are handled by passing them to the BIOS;
> > at that point, the Linux kernel can execute BIOS calls by dropping
> > down to real mode.
>
> c) Build a better BIOS.
>
> Though I think it would be nice to be able to break the kernel down,
> much further than is currently possible, to make feasible
> linux-booting-linux or really small, embedded linux. A lot of stuff is
> linked into the core kernel image by default that is simply not needed
> when running a "lean lean" kernel.
And apparentely because I love to get beaten on:
d) use EFI
It has all of this stuff already done. It was designed to allow
arbitrary mini drivers to be loaded, etc. You could write a driver for
ext2. You can write a driver to boot off of your favorite device.
Plus, EFI was also intended for OS' to install it themselves. You don't
need vendors to pre-install it for the user when they buy their machine.
Please, save all flames for another time when I really deserve them.
JE
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This archive was generated by hypermail 2b29 : Thu Jun 15 2000 - 21:00:33 EST