Date: Mon, 2 Jul 2001 17:06:08 +0200 (MEST) From: schilling@fokus.gmd.de To: mckay@thehub.com.au, schilling@fokus.gmd.de Cc: freebsd-scsi@freebsd.org, ken@kdm.org Subject: Re: Problems reading burned CDs Message-ID: <200107021506.RAA20637@burner.fokus.gmd.de>
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>From mckay@thehub.com.au Mon Jul 2 16:26:06 2001
>>The more features cdrecord gives you the more sense is in having a unique
>>interface.
>I still have hopes that a unified CD burner driver interface can be
>built. There are many ways to burn a CD (unfortunately!) but we only
>need a few by default. For example, I believe it is safe nowadays to
>write everything as multisession (left open). That could be the
>default. Also, now we know that TAO causes certain problems, we can
>pad by default. And so on. Maybe raw writing becomes the default too.
>It's too complicated the way it is.
The unified cd recorder interface is the top level of libscg.
It is > 99% compatible on any of 29 supported OS.
You will not really try to write your own cd recording program inside the kernel
and this even in two versions (SCSI & ATAPI) will you?
>>The latest cdrecord e.g. introduces RAW writing which is thew only way
>>of doing DAO on Philips drives. Note that Philips OEM drives are dominating
>>the drive market now.
>Can this be automatically detected? Then the best write mode can be
>used without the user being involved.
Cdrecord tells you a supported mode if you select the wrong one.
>What's the simplest way (using cdrecord) to write such a disk? I'll test
>it on my gear. I am not in the habit of intentionally making difficult to
>read CDs. That happens only by accident. :-) So I could use a hint.
Create any CD with only one medium sized file on it (e.g. 2-10 MB).
use mkisofs -no-pad to create a ISO image. Check whether this image
will not be a multiple of the kernel's FS buffer size.
Write the image in TAO, mount the media and do a dd from the file on the
ISO FS.
>By the way, Jörg, do you have expert knowledge of CDROM filesystems,
>as well as CD burners? I have a multisession Joliet CDROM that is
>completely unreadable on FreeBSD (mount reports cd9660: /dev/acd0c:
>Invalid argument). It has one more track than it has sessions. The
>extra track is between the others, and is 63 seconds long. It reads
>perfectly on Win98.
Well first: Joliet is non standard, second: you cannot really create
a multi session CD without Rock Ridge and with only Joliet on it.
The reason is that there is no relation between the Joliet filenames
and the ISO filenames.
If the CD is XA-mode 2 it may be that your CD-rom or the kernel driver
does not support to read XA.
Jörg
EMail:joerg@schily.isdn.cs.tu-berlin.de (home) Jörg Schilling D-13353 Berlin
js@cs.tu-berlin.de (uni) If you don't have iso-8859-1
schilling@fokus.gmd.de (work) chars I am J"org Schilling
URL: http://www.fokus.gmd.de/usr/schilling ftp://ftp.fokus.gmd.de/pub/unix
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