[Libcdio-devel] Re: Device::Cdio::???? and CD bootloader

[Rocky Bernstein]

Comments in line.

On Sun, Apr 26, 2009 at 1:59 PM, Tong Sun <address@hidden> wrote:

> Thanks a lot Rocky.
>
> I haven't got around to subscript to address@hidden and ask the
> question yet, and you've already replied. Thanks.
>
> I'm CCing address@hidden this time, so that other people can
> benefit as well. Thus, I use full quote to reply. Moreover, for the
> archive, the reason for my question is,
>
> Many .iso files come with size much less than 700M. So it would be a waste
> of
> CD spaces to burn them as-is -- I want to add more files to them (then
> pack them up again as iso) before burning them. So the most important
> step is to extract the CD boot loaders (mainly for Windows based
> bootable .iso images), so as to make it bootable again.
>
> On Sun, Apr 26, 2009 at 10:28 AM, Rocky Bernstein <address@hidden> wrote:
> > Device::Cdio is a Perl wrapper around libcdio, which is a library for CD
> and
> > ISO9600 reading and it has provisions for the some of the various
> ISO-9660
> > extensions. If there is something in the "El Torito" extension that
> libcdio
> > doesn't handle libcdio should be corrected.
> >
> > So I believe it possible to read the boot-loader information. Adding more
> > stuff to the end to write a new image is a different problem.
> >
> > example/iso2.pl from the Device::Cdio shows how to read a specific sector
> of
> > an ISO9660 image such as sector 17. Most CDs have just one session so
> this
> > "first" versus "last" session is usually irrelevant. I know in the C
> library
> > there is a way ascertain how many sessions an image has, I'm not sure if
> > that has been made accessible in the Perl library.
>
> Thanks, I took a look at the example/iso2.pl, and find that actually
> the better example is examples/iso3.pl for my case, because iso2.pl
> read from CD-ROM or .cue file, whereas iso3.pl reads from ISO 9660
> image file, which is what I want. Will try...


Ok. Great.


>
>
> BTW, what does lsn stands for?


 Check out the glossary
http://www.gnu.org/software/libcdio/libcdio.html#SEC61

>
>
> > And on the topic of the Perl library, I should say that the Python and
> Ruby
> > libraries have been better maintained (by me) than the Perl library. So
> if
> > you can use either the C (best) Ruby (next best) or Python (3rd best) it
> may
> > be better than Perl.
>
> Hmm.., I don't know Ruby or Python. I prefer Perl because I want to
> write minimum code. How about your iso-read command?
>

>
> http://www.linuxcertif.com/man/1/iso-read/
>
> Seems it is only file based, instead of sector based reading.


Yep, it's file based. However if someone wants to submit patches to add
options to make it sector based, I'm amenable to that.


>
> Thanks
>
>
> > If you get to the stage of wanting to write back the ISO9660 image, you
> are
> > aware of mkiso9660. vcdimager has C routines for writing CD images as
> well,
> > but someone would have to extract that and turn it into a library much as
> > libcdio was done.
> >
> > Good luck.
> >
> > On Mon, Apr 20, 2009 at 1:36 PM, Rocky Bernstein <address@hidden> wrote:
> >>
> >> Just to let you know that I got your email. . . .
> >>
> >> Also you may want to try to post on mailing list: address@hidden
> >>
> >> On Mon, Apr 20, 2009 at 12:37 PM, Tong Sun <address@hidden> wrote:
> >>>
> >>> Hi Rocky,
> >>>
> >>> I'm looking for ways to extract the CD boot loaders. Do you know how
> >>> to do it with your Device::Cdio::???? packages?
> >>>
> >>> FYI, I'm looking for ways to extract the CD boot loaders, mainly for
> >>> Windows based bootable .iso images, since I know how to make Linux
> >>> based bootable .iso images. The answer that I got was Windows based:
> >>>
> >>> bbie
> >>> http://www.nu2.nu/bbie/
> >>>
> >>> Ref:
> >>> http://www.boot-land.net/forums/index.php?showtopic=6370
> >>>
> >>> The reason why I need to do it is explained in
> >>> http://www.boot-land.net/forums/index.php?showtopic=6372
> >>>
> >>> May .iso files come with size much less than 700M. So it would be a
> waste
> >>> of
> >>> CD spaces to burn them as-is -- I want to add more files to them (then
> >>> pack them up again as iso) before burning them.
> >>>
> >>> Also in the thread, tech details about CD bootloader:
> >>>
> >>> According to "El Torito" Bootable CD-ROM Format Specification,
> >>> http://en.wikipedia.org/wiki/El_Torito_(CD-ROM_standard)<http://en.wikipedia.org/wiki/El_Torito_%28CD-ROM_standard%29>
> >>>
> >>>
> http://www.phoenix.com/NR/rdonlyres/98D3219C-9CC9-4DF5-B496-A286D893E36A/0/specscdrom.pdf
> >>>
> >>> "The "Boot Record" must reside at sector 11 (17 decimal) in the last
> >>> session
> >>> on the CD."
> >>>
> >>> Thanks for your help.
> >>>
> >>> tong
>