Mailinglist Archive: packet-writing (21 mails)

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Re: Non-RW media; WORM hopes
  • From: Phillip Susi <psusi@xxxxxxxxxx>
  • Date: Mon, 18 Jun 2007 14:02:21 -0400
  • Message-id: <4676C8AD.3060404@xxxxxxxxxx>
RB wrote:
I wish I had good news...  Reading through the source of cdrwtool
(udftools-1.0.0b3) and using strace, I'm able to follow the execution
of '-m' up to the point that it actually tries to send the packet
containing the format to the CD (cdrwtool.c:424), which fails
immediately with a return value of EIO.  I thought it was the fact
that cdrwtool.h tries to reference HZ in it's timeouts, but hardcoding
those to sane values did nothing for me.  In three different drives
from three different manufacturers, I get the following with virgin
Imation CD-R media:

[root@tst ~] cdrwtool -d /dev/hdc -m 359846
using device /dev/hdc
formatting 359846 blocks
1751KB internal buffer
setting write speed to 12x
wait_cmd: Input/output error
Command failed: 04 17 00 00 00 00 00 00 00 00 00 00 - sense 05.30.06
format disc: Illegal seek

After refreshing my memory from the MMC standard, it looks like you can not use the FORMAT UNIT command on CD-R media, which is what cdrwtool is trying to do there. If I am reading the standard correctly however, you can issue a RESERVE TRACK command with the proper mode settings and then proceed to write to that track a packet at a time. I am not sure if it does it correctly or not, but cdrwtool has a -r switch to tell it to reserve a track. This may correctly set up the mode page and reserve the track, then allowing you to write to it 32kb at a time. If you eject the cd or reboot though, I think the mode page will need to be set up again before you can resume writing, and I don't see a way to do that currently.


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