Re: 4 meg boot failures

From: Michele Andreoli (
Date: Sat Oct 28 2000 - 13:27:08 CEST

On Fri, Oct 27, 2000 at 07:29:53PM -0700, winsor SMP nicely wrote:
> Michele
> If someone were to strip USR portion (of unneeded for "clone and setup" binaries and such)

Oh, thank you for the question: the answer is ROOT.gz! We have in ROOT.gz
the minimal tool able to run the basic scripts that unpack the images
from the hard-disks. Example: command as "ifconfig" are in USR.
ROOT.gz contains the shell interpreter and libc5. The editor itself is
in USR (another example).
It is not possible to reduce ROOT.gz again, because it is not possible
to reduce libc5. These are the sizes:

470 lib
3028 /bin

In /bin you have: ash, gzip, bzip2, tar, ls, rm, mount etc.
for base scripting.

> and rebuilt a new USR on another partition. (with a smaller size???)
> And then rebuilt B/R/U disk, would this allow a greater chance of success, to at least clone an "extremely" barebones muLinux system to disk, and then upgrade via setup for full muLinux installation after creating swap file???
> Over the last year or so this "4meg" issue has appeared many times.
> It would be good if this could be resolved...............

When I trashed by Debian, I was trying exactly that. But USR is left
out from this discussion. For 386 with 4M we need TWO floppy disk, as
ancient Slackware:

                BOOT (floppy 1) uncompressed
                ROOT (floppy 2) uncompressed

Currently, we have a single floppy with three segment:

                BOOT (uncompressed) ROOT (compressed with gzip)
                and USR( highly compressed with bzip2)

Only BOOT (the kernel) and ROOT (the shell) are involved in
installation. So, I'm managing a new floppy disk with ROOT on it,
but uncompressed, i.e. *mountable*.

After the BOOT floppy, the kernel ask

                "Please insert the ROOT floppy"

Luckyly, this feature is still present in 2.0.36 kernel. It
trasform the system in Amiga1000, and acts like (old) DOS when booting
from the rescue disk.

Modern rescue disk (from Win98) use ramdisks, like muLinux does.
So, we have to emulate old DOS, because it works without
additional RAM.

It is very easy to create the ROOT floppy disk:

                # fdformat /dev/fd0H1722
                # mkfs.ext2 /dev/fd0H1722
                # mount /dev/fd0H1722 /a
                # gzip -d ROOT.gz
                # mount -o loop ROOT /mnt
                # mkdir -p /mnt/startup/init
                # cp -a /mnt/* /a
                # umount /a; umount /mnt

Now, boot using the BOOT+ROOT+USR muLinux floppy, and at boot

                boot: mulinux load_ramdisk=0

Put the new ROOT floppy, at request.
Now, we have muLinux running from the floppy disk, with RAM->0.


"I'd like to conclude with a positive statement, but I can't remember any.
Would two negative ones do?"			-- Woody Allen
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