[Libburn] Re: How to pipe stdin to CD-RW ?

[scdbackup at gmx.net]

Hi,

> > [my first diff about burn_source_get_size et al.]
> >
> Derek Foreman wrote :
> I'll look this over properly sometime next week,
> I'm under a lot of time pressure right now.

Don't hurry yet.

I will post a new diff soon.
(Plus a condensed problem list)


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If a drive device file (here /dev/sg0) offers r-permission
but not w-permission then the call  burn_drive_scan()  hangs
quite forever. The CPU load goes up to 100 %. 
Ctrl+C is necessary.

So this is an evil user trap:
  crw-rw-r--    1 root     disk      21,   0 Sep 23  2003 /dev/sg0

There might be valid sysadmin reasons for such a setting.
Then it prevents the use of any other drive, too.


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I have to correct my findings on SuSE 7.2, kernel 2.4.4
because yesterday i did not run the drive search as
superuser.


SuSE 7.2, kernel 2.4.4, ide-scsi :

cdrskin_static: finds both CD-ROM and CD-RW , works as expected

libburn-0.2.ts:  finds both CD-ROM and CD-RW , works as expected


This does not explain why the IDE CD-ROM on 2.4.21 system
does not show up even for the superuser. 


Without ide-scsi on 2.4.4 : 
cdrskin_static finds SCSI CD-ROM but not IDE CD-RW.


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> > Derek, by some reason i do not get your replies via mail
> > but can only see them in the archives.
> > My own postings do reach me.
> > Any idea why this happens ?
>
> In technical terms, I believe this happens because your mail provider 
> "sucks". :)

That would be a very selective sucking.
I get my own postings within a minute. (shrug)

  Received: from gabe.freedesktop.org (EHLO gabe.freedesktop.org)
      [131.252.208.82]
    by mx0.gmx.net (mx081) with SMTP; 06 Dec 2005 23:03:29 +0100
  Received: from gabe.freedesktop.org (localhost [127.0.0.1])
        by gabe.freedesktop.org (Postfix) with ESMTP id 6D1419EEED;
        Tue,  6 Dec 2005 14:03:25 -0800 (PST)

Four seconds from gabefreedesktop.org's Postfix to mx0.gmx.net.

GMX own ad spam sucks. But their tech works 99% flawlessly.
(I got my spam filter off. So that cannot be the cause.)

Whatever. I'll watch the archive. That should suffice.


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> > i wrote :
> > That would be in fact the beginning of a cdrecord skin
> > for libburn.
> 
> Derek Foreman wrote :
> I've always thought this would be a really nice thing to have, but never 
> bothered to do it myself.

Now it is started, at least. :))

It would be preferrable to have cdrskin included in libburn-*.tar.gz
as a member of the ./test directory or of a ./cdrskin directory.
But i'm not suffciently done with its libburn enhancements,
yet. I want them to look acceptable when i submit it. :))

Nevertheless, a first snapshot is uploaded as
  http://scdbackup.webframe.org/libburn-0.2.ts.tar.gz
(this is not intended as a permanent fork)

I am done with system compatibility checks, so far.
(Seems to work with 2.4 and 2.6 kernels.)
Now i am adding a page about cdrskin to the website of scdbackup.
  http://scdbackup.webframe.org/cdrskin_eng.html


> What are multi-volume star backups?

star is an enhanced tar-compatible archiver by Joerg Schilling.
http://cdrecord.berlios.de/old/private/star.html

It is my first choice for portable full backups of filesystems,
e.g. for disaster recovery preparation.
Together with rescue system RIP-14.5 i successfully made a
system backup, erased the partition by random bytes, and 
restored that backup. I had to boot the restored system via 
RIP's bootloader GRUB and to re-run the LILO install command.
Then it was up again. Neat.
(My first choice for arbitrary file archiving is afio, because
of its unique way to keep compressed archives recoverable
after small bad spots. My first choice for harmless user data
files is ISO-9660, of course.)


Joerg added features to cdrecord to make the tape oriented
multi-volume capability of star available for optical media.

My own project does not make use of multi-volume star but
either produces multiple independent star-archives or it
chops a giant star archive onto several media.
(Yes, this all runs with libburn now. :)


> > I myself will not strive to achieve the versatility of
> > cdrecord.
>
> Well, I strive to make a library that's capable of that versatility. :)

Not a small goal ... Ok. I'm with you.

There are still some aspects of data recording which could
need improvement (drive and media status, eject, speed query,
speed setting, writing of streams of unpredictable length,
tolerance towards read-only /dev/sgX, ...).
For these i will gladly volunteer as a tester.

I am also ready to become maintainer of cdrskin within
the libburn project (have to learn about CVS). It would
be structured and written my style but i would be open
to any proposal that brings real profit to the code.
The decisive libburn maintainers would have a veto
on cdrskin activities (on the risk to see an exodus or
a fork, of course).

My idea is to invite other cdrecord users to contribute
their knowledge about its capabilities and behavior.
We would either try to implement cdrecord features by
help of the existing libburn or we would develop qualified
requests for enhancements of libburn.

For that, i would announce libburn's cdrskin at
cdwrite at other.debian.org, the mailing list for
cdrecord and growisofs.
Rather than bitching around, unsatisfied users of cdrecord
may then show wether they can do it better than Joerg.
(It will be a great challenge to my social skills.)

Of course, we would have to be patient with you.
At least the cdrskin sub project would not impose
unrealistic expectations.


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What will happen if i try to burn a DVD+RW via libburn ?


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Have a nice day :)

Thomas