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Date:	Sun, 13 Feb 2000 03:53:07 -0500
From:	Jens Axboe <axboe@suse.de>
To:	Linux Kernel <linux-kernel@vger.rutgers.edu>
Subject: Announce: CD-RW packet writing

Hi,

I've made the first (somewhat) functional release of packet writing
for CD-RW devices available. Current patch is against 2.3.44 and
can be found at:

ftp://ftp.*.kernel.org/pub/linux/kernel/people/axboe/packet

Packet writing allows CD-RW devices to be written to transparantly,
i.e. without a dedicated cd recorder program. It differs from the
normal track/disc/session at once methods in that 

a) you don't have to master any images
b) buffer underruns cannot occur

The end results is that files can be copied directly to the device,
as with any other disc. This is just like the Windows programs PacketCD
or DirectCD.

Devices are setup much like loop devices, with a dedicated pktsetup
program (e.g. pktsetup /dev/packet0 /dev/hdd). Then you can write
a file system to the device with mkfs.ext2 or similar, although
I do recommend using UDF for this purpose. The UDF tools
package contains a version of my cdrwtool program that can be used
to blank/format a disc and then write necessary UDF structures.
Patch for that is included in the tar ball.

Current limitations:

- Only ATAPI devices are supported. SCSI should be easy, I just
  haven't done it yet.
- Only CD-RW discs supported. To support CD-R we need some support
  from UDF to write much larger variable sized packets to the device.
  Ben Fennema and I are looking into that.
- Changes ll_rw_blk merging logic, so don't run it on any systems
  with precious data. It hasn't given me problems, but you never know...
- Not the fastest thing in the world.
- First alpha release, bound to be lots of bugs!

If you would like to help test this beast and improve it, please
contact me privately. There's no mailing list available yet...

-- 
*  Jens Axboe <axboe@suse.de>
*  Linux CD-ROM Maintainer
*  http://www.kernel.dk

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