[Udpcast] Re: Give parameters through isolinux.cfg

Alain Knaff alain.knaff at lll.lu
Sun Feb 6 23:27:26 CET 2005


On Wednesday 10 November 2004 10:42, Stephane wrote:
> Hi,
>
> I've unsuccessfully tried to send a message to the list.
> (I receive list's mail).
>
> I'm trying to solve the problem, contacting mailman...
> But I would like to send you my post to see if you can help me:
> ******************************************************************
> I would like to add precustomized images to a multiboot CD using isolinux.

In that case, you need to instruct makeImage to give you the initrd
(-i flag), rather than a finished cd or floppy image:

 /usr/lib/udpcast/makeImage -i initrd -k /boot/vmlinuz-2.6.10udpcast

Then you store that initrd and the corresponding kernel on the CD, and
add the following paragraph to your isolinux.cfg file:

default linux
label linux
  kernel vmlinuz
  append root=01:00 initrd=initrd

(assuming that the initrd is still called initrd, and the kernel
vmlinuz)

Note: for 2.6 kernels, you need root=01:00, whereas for 2.4 kernels,
you need root=/dev/ram0

> I would like to only have one image and send parameters through the 'label'
> line in isolinux.cfg

The label line is not acessible to the kernel, this is only for the
boot loader's (Lilo, Grub, Syslinux) own usage (typically used as menu
headers)

However, you can add a limited amount of parameters to the append
line:

default linux
label linux
  kernel vmlinuz
  append root=01:00 initrd=initrd umode=rcv auto=yes

This passes the parameter umode=recv and auto=yes to udpcast, so it
won't ask whether it should behave as a receiver or as a sender.

Unfortunately, there is a limitation in the kernel, which limits you
to 6 such parameters, if I remember correctly.

> It would be nicer than customizing one image for each config.

But what you can do is put those parameters that are not likely to
change between each config into the initrd, and only leave those that
change on the kernel command line, in order not to overflow the
parameter count.

Regards,

Alain




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