Re: Writing to DVD
Hi,
> I'm trying to get a better understanding of writing DVDs under Debian.
> I'm using a LG 4082B DVD burner, supporting DVD+R(W),
> DVD-R(W) and DVD-RAM. It's installed in a machine running a 2.4 kernel,
> which has NOT been patched for packet writing, UDF writing or any other
> form of DVD support.
No module ide-scsi governing the writer either ?
> Most resources suggest using dvdrtools for writing to DVD-R(W) and
> dvd+rw-tools for writing to DVD+RW. Both of these tools rely on the use
> of ISO9660 filesystems. dvdrtools requires an iso file to be created
> before writing to disc, dvd+rw-tools does it on-the-fly through
> growisofs. I have had no problems creating discs using these tools.
I use with my LG GSA-4082B on Linux 2.4 under ide-scsi
emulation either dvd+rw-tools (growisofs 5.21)
http://fy.chalmers.se/~appro/linux/DVD+RW/tools/?M=D
or cdrecord-ProDVD 2.01b31
ftp://ftp.berlios.de/pub/cdrecord/ProDVD
Each of them works for both DVD+RW and DVD-RW.
Each of them can be used for writing arbitrary
images, not only ISO9660. (I use afio for certain
purposes.)
With growisofs :
growisofs -use-the-force-luke -Z /dev/sr0=/my/image
resp.:
generate_my_image_to_stdout | \
growisofs -use-the-force-luke -Z /dev/sr0=/proc/self/fd/0
(see man growisofs)
With kernel 2.4 and growisofs it seems to be necessary
to run the writer under ide-scsi emulation. Therefore
the SCSI-address /dev/sr0 rather than /dev/hdc .
Before use, DVD-RW need to be formatted. I prefer
mode "Restricted Overwrite" despite its quite
misleading name :
dvd+rw-format -force /dev/sr0
This makes DVD-RW behave much like DVD+RW (for growisofs).
With cdrecord-ProDVD (installed as "cdrecord") :
cdrecord dev=0,0,0 driveropts=burnfree -data -sao /my/image
(see man cdrecord)
Without ide-scsi emulation you will have to use prefix
ATAPI: (or ATA: ?) with the drive address. Like
dev=ATAPI:0,0,0
(see ftp://ftp.berlios.de/pub/cdrecord/README.ATAPI
I never tried that myself but know of people who did.)
Before re-use with cdrecord-ProDVD, DVD-RW need to be
blanked like CD-RW :
cdrecord dev=0,0,0 blank=fast
DVD+RW get formatted automatically by both growisofs
and cdrecord-ProDVD. No special precautions needed to
overwrite them.
> DVD-RAM discs can have an arbitrary filesystem placed on them and be
> mounted. eg.
> # mke2fs /dev/cdrom
> # mount -t ext2 /dev/cdrom /cdrom
> # cp * /cdrom
I tried that with Panasonic LM-AF120U3 media.
Seems not to work reliably with ide-scsi (MD5 errors
when verifying content of a file), is darn slow and
larger backups clogg the i/o buffers which then
cannot be used for hard disk i/o.
Do you get better results without ide-scsi ?
> It appears a similar method can also be used with DVD+RW discs, however
> I have also tried writing binary streams to DVD+RW discs. For example
> # umount /cdrom
> # tar -Mcvf /dev/cdrom /some/files
> I don't understand why this works, but the resultant disc appears to be
> verbatim.
Wow.
Now if you dump just a raw file to the media
cat /my/fat_file >/dev/cdrom
and compare it with the original
diff /my/fat_file /dev/cdrom 2>&1 | less
does it really match ? (At least up to the
length of /my/fat_file)
> How dependant is the success of the last two methods on the model of DVD
> writer used? I understand that such discs would not be readable under
> most other operating systems, but would they be readable under Linux on
> other machines with generic DVD-ROM drives or DVD writers? Why can
> DVD+RW discs be mounted and used that way, but DVD-RW discs can not?
The ext2 file system of your DVD-RAM example
should mount on old Linux systems.
I'm not sure about the ability to use DVD-RAM
devices properly. 2.4 and 2.6 kernels should do.
(My system does not really support that theory.)
Traces in the web indicate that 2.0 and 2.2
were subject to some DVD-RAM related patching.
I am willing to bet that you cannot mount
on Linux a DVD written with tar cf /dev/cdrom
To be mountable, a DVD needs to hold the
image of a mountable file system. I am
not aware that there is a file system
driver for tar-archives in Linux.
Nevertheless you should be able to read
a tar image with any Unix-style system
by just using the CD-ROM device file :
tar tvf /dev/cdrom
Concerning MS-Windows, Andy Polyakov stated :
"tar ztf '\\.\d:' and there're other ways... a."
I am still a bit in doubt about the
general usability of your writing method.
My approach would be
tar cvzf - /some/files | \
growisofs -use-the-force-luke -Z /dev/sr0=/proc/self/fd/0
(tar option -M is still a bit obscure to me after
reading man and info tar. Is it about end-of-tape
handling ?)
The methods for reading the tar archive would be
the same as above.
Have a nice day :)
Thomas
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