Re: nfsroot anyone?

Miquel van Smoorenburg (miquels@drinkel.ow.org)
Mon, 18 Mar 1996 23:52:49 +0100 (MET)

In article <199603181437.OAA24618@snowcrash.cymru.net>,
Alan Cox <alan@cymru.net> wrote:
>> I'm going to take a look into this ASAP. However, I don't think implemen-
>> ting BOOTP into the kernel (as with 1.3.75) is such a good idea. It blows
>> up the kernel binary for being used just once. This should instead go into
>
>This is part of a global Linux memory/segment planning problem. There is no
>way to put all the init code into a discardable memory area thrown after
>boot.
>
>> the bootrom, which then sends the necessary parameters from the BOOTP
>
>The floppy disk drivers on our campus for example lack a boot rom ;)
>
>> user process. So, why should we implement BOOTP into the kernel? IMHO, we
>> should discuss this further.
>
>For non boot rom cases. I hope as bzImage/modules gets further a discardable
>bootp will be practical

Well, around 1.3.30 or so I had a patch similar to the bzImage stuff;
I overloaded the chroot() system call to change the root file system
and discard the old root file system. This way I booted a kernel from
a floppy with the floppy as its root file system. It set up the networking
itself, ifconfig, route, etc all on the first root filesystem. It then
mounted an NFS filesystem on /root and changed the root file system to
/root, freeing the floppy root. The last thing was to exec /sbin/init
et voila.. Linux kernel with NFS root without the baggage in the kernel.

Ofcourse you can now do the same thing with the initrd support; just
include bootpclient (or dhcpclient), ifconfig, route and some shell
scripts or C program to glue things together on the initial ramdisk.
As I said above, you don't even need the NFS root option. Just mount
the rootfs with NFS on /linuxrc.

Did I miss anything?

Mike.

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