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RE: growisofs with -b problem



Well after some more invetigation here are the facts:
1. I was able to boot from my DVD+RW using growisofs with the following
command:

2.It seems there is a bug in mkisfos with "-b" option. Let's say I want to
backup
	/home/me/x/y/z
but my boot image is located in
	/home/me/x/y/a
So when I try to specify ../a/boot.img - mkisofs fails to find it, even
though it
is a relative path. Could it be that stuff starting with ../ or ./ does not
work?
BTW, this is the format I tried 1st, just did not inlcude in my 1st mail.

3. What I was trying to do was to create a DVD bootable disk with a tar
archive
of the whole system. I have a small 1st disk that was more then 50% full, so
creating
a tar image first was not an option. It sounds like it is not possible. I
will have to place a bootable disk image and the tar archive on a separate
individual disks.



-----Original Message-----
From: appro@fy.chalmers.se [mailto:appro@fy.chalmers.se]
Sent: Tuesday, August 19, 2003 3:59 AM
To: eugene rikel
Cc: cdwrite@other.debian.org
Subject: Re: growisofs with -b problem


> Q1: is it possible to boot from a DVD disk?

Noone will be able to answer this question with 100% certainty. If your
BIOS can boot from CD, it most likely can boot from DVD as well. But
there might be limitations, e.g. bootstrap image has to be in the
beginning om media perhaps, nobody knows for sure if there're any
limitations or not...

> I was able to create DVD disk with a following command:
> tar -cv ./me/rpm |
>
/mnt/linux2/home/me/erikel/tools/dvdPrw/dvd+rw-tools-5.9.4.4.4/growisofs -Z
> /dev/scd0=/dev/fd/0 -b
> /home/me/erikel/tools/tomsrtbt/tomsrtbt-2.0.103.ElTorito.288.img -c
boot.cat

You should really look at what growisofs says upon startup (use -dry-run
to examine this option without starting recording).

> Executing 'builtin_dd if=/dev/fd/0 of=/dev/scd0 obs=32k seek=0'

As you can see it has performed verbatim copy of standard input
(/dev/fd/0) to DVD. This [among other things] means that whenever you
specify -Z /dev/X=Y, all mkisofs options are basically discarded.

> However my computer would not boot from that DVD+rw disk.

What you've done here is mastered tar-formatted media, the one you're
supposed to access with 'tar tf /dev/scd0', not mount or boot from. It's
not a DVD or DVD+RW or growisofs or mkisofs issue, you've misunderstood
the concept:-)

> Q2: Why not? or is the answer to Q1 is "no"?
>
> So then I tried:
> #
>
/mnt/linux2/home/me/erikel/tools/dvdPrw/dvd+rw-tools-5.9.4.4.4/growisofs -b
> tomsrtbt-2.0.103.ElTorito.288.img -c boot.cat -Z /dev/scd0 -R -J
/tmp/me.tar
> But this command could not find the image file?
> Q3: Did I specify the wrong path?

Yes. And this is not a DVD or DVD+RW or growisofs issue either. mkisofs
expects -b argument to be "relative to the source path," you can't just
collect boot image and files like you tried to, when you master a
bootable media. Read mkisofs manual, search google for receipt/tutorial
on how to make bootable CD.

Volker Kuhlmann wrote:

>   * growisofs by <appro@fy.chalmers.se>, version 5.11,
>   - usage: growisofs [-dvd-compat] [-overburn] [-speed=1] \
>            -[ZM] /dev/cdrom <mkisofs options>
>     for <mkisofs options> see 'mkisofs -help'
>
> Which kind of tells you that all the mkisofs options need to be after
> all the growisofs options.

Not 100% true. <mkisofs options> are suggested to be passed last in
command line mostly for aesthetic reasons. In reality you can actually
mix them with "native" growisofs options. Well, I probably should have
never said this, as certain discipline in composing command line does
help to understand what's going on:-)

> You could also create a disk image first with mkisofs and then burn that
> with growisofs.

One of the practical(!) ideas behind growisofs is to be excused from
creating intermediate image prior recording. It's definitely and
absolutely good idea for figuring things out (as you can check the image
by mount -o ro,loop), but if you're confident in what you're doing,
mastering of intermediate image is just a waste of time and resources:-)
Cheers. A.



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