Mailing List Archive

On Tue, 26 Mar 2002 17:35:03 -0700 (MST), Dermot Bradley
<bradley@oldcolo.com> wrote:

>What exactly do I need to put in my isolinux.cfg file? Do I *need* to have
>a initrd or can I do without? How do I tell ISOLINUX where to find the
>root filesystem (or does it figure it out itself)?
Where is the root fs?

--
giulioo@pobox.com

> > >What exactly do I need to put in my isolinux.cfg file? Do I *need* to
> > have a initrd or can I do without? How do I tell ISOLINUX where to
> > find the root filesystem (or does it figure it out itself)?
>
> Where is the root fs?

Its the CD's top level - I want ISOLINUX to load the kernel, mount the
CDROM read-only as "/", have no swap, and run a simple shell-script to
install files onto the machine's hard disk.

Is this possible?

--
Dermot Bradley
bradley@oldcolo.com, bradley@debian.org

> > Where is the root fs?
>
> Its the CD's top level - I want ISOLINUX to load the kernel, mount the
> CDROM read-only as "/", have no swap, and run a simple shell-script to
> install files onto the machine's hard disk.
>
> Is this possible?

This is possible, yes. you can make a bootable CDROM with isolinux,
with a kernel that supports scsi CDROM emulation. then your 1st cd-drive will
always be /dev/scd0 (iirc). you can say to your kernel that that is our /
by using rdev: 'rdev <kernel image> <root fs>'. if your kernel would be
called vmlinuz, then you should type 'rdev vmlinuz /dev/scd0'.

now you can make a minimal distribution on the CD, and do whatever you want
from init. Tip: you can replace /sbin/init with a shellscript that can do
all the work for you. And if you statically compile busybox, you won't need
any libraries or whatever to do stuff.

HTH, HAND

grtz, Tijn

--
2:36AM up 28 days, 15:52, 6 users, load averages: 0.05, 0.05, 0.01

> This is possible, yes. you can make a bootable CDROM with isolinux,
> with a kernel that supports scsi CDROM emulation. then your 1st cd-drive
> will always be /dev/scd0 (iirc). you can say to your kernel that that is
> our / by using rdev: 'rdev <kernel image> <root fs>'. if your kernel
> would be called vmlinuz, then you should type 'rdev vmlinuz /dev/scd0'.

Well the CD will always be used via either native SCSI or SCSI
emulation. As I'll be using devfs I guess the device name would actually
be /dev/cdroms/cdrom0

I've never used rdev before - does it actually alter the contents of a
kernel image? If so then I guess "rdev /lfs/boot/vmlinux
/dev/cdroms/cdrom0" would do what I need.

--
Dermot Bradley
bradley@oldcolo.com, bradley@debian.org

On Fri, 29 Mar 2002, Dermot Bradley wrote:

> I've never used rdev before - does it actually alter the contents of a
> kernel image? If so then I guess "rdev /lfs/boot/vmlinux
> /dev/cdroms/cdrom0" would do what I need.

Can I just have "APPEND root=/dev/cdroms/cdrom0" in my isolinux.cfg
instead?

--
Dermot Bradley
bradley@oldcolo.com, bradley@debian.org

On Fri, Mar 29, 2002 at 09:03:01AM -0700, Dermot Bradley wrote:

> Well the CD will always be used via either native SCSI or SCSI
> emulation. As I'll be using devfs I guess the device name would actually
> be /dev/cdroms/cdrom0
>
> I've never used rdev before - does it actually alter the contents of a
> kernel image? If so then I guess "rdev /lfs/boot/vmlinux
> /dev/cdroms/cdrom0" would do what I need.

it's about the device number on your build-system. you need to point to the
device existing on your build-system. if you have no devfs on your build-
system, then you use /dev/scd0. If you do have devfs, then you're probably
right (I didn't have the time yet to study devfs).

Yes, rdev alters the kernel image.

HTH, HAND

grtz, Tijn

--
5:18PM up 30 days, 6:34, 6 users, load averages: 0.08, 0.10, 0.08

On Fri, Mar 29, 2002 at 09:04:54AM -0700, Dermot Bradley wrote:
> On Fri, 29 Mar 2002, Dermot Bradley wrote:
> Can I just have "APPEND root=/dev/cdroms/cdrom0" in my isolinux.cfg
> instead?

yes you can, I guess :)

> --
> Dermot Bradley
> bradley@oldcolo.com, bradley@debian.org
>
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grtz, Tijn

--
5:22PM up 30 days, 6:38, 6 users, load averages: 0.02, 0.07, 0.07