From mboxrd@z Thu Jan  1 00:00:00 1970
Message-ID: <4aea050db294e394f530cdd63b87e304@plan9.bell-labs.com>
Date: Mon, 17 Mar 2008 21:13:18 -0400
From: geoff@plan9.bell-labs.com
To: 9fans@9fans.net
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Subject: [9fans] new cdfs for DVDs and BDs
Topicbox-Message-UUID: 7ad2a7a2-ead3-11e9-9d60-3106f5b1d025

There's a new cdfs on sources that also knows how to read and write
data tracks on DVDs and BDs (Blu-ray Discs, the makers claim); see
cdfs(4) for details.  I've tried to test all combinations of media
(CD, DVD-, DVD+, BD) × (-ROM, -R, -RW) × (single-layer, dual-layer),
which works out to 24 combinations, but may have missed some
(definitely missed dual-density CDs).  DVD-RAM is untested but might
just work; the rewritable media are much less troublesome than the
write-once media.  HD DVD is untested; it might just work, but it's
fading rapidly.

I've tested PATA (IDE) and SATA burners, but not USB, which ought to
work (slowly for now) via usbdisk, nor SCSI.

If you haven't been paying attention to optical media lately,
dual-layer BDs can hold 50GB, which is enough to be interesting for
backups and archiving.  There's no officially-sanctioned way (yet) to
incrementally add tracks to a disc over a longish interval, but
empirically it appears that just not removing the /mnt/cd/wd file
until you've written the last track will allow dribbling tracks out to
disc.  100 tracks, each containing a 512MB venti arena, should roughly
fill a dual-layer BD. It's also possible that I'll implement packet
(incremental) writing.