is DragonFly advertising wrong block device to K3B?

Matthew Dillon dillon at
Fri Dec 26 10:14:59 PST 2008

:K3B autodetects my single DVD burner as /dev/cd0c (3,0,0).
:Trying to change it to /dev/cd0 says theres no burner there,
:The weird thing is burning to /dev/cd0c will work for data CDs but fails for 
:audio CDs. So I did a test with cdcontrol to play an audio cd and when I use 
:the cdcontrol's default setting cd0c, it gives me Input/Output Error but 
:using just cd0 (or acd0) works.
:petr at elevator:/home/petr# cdrecord --scanbus
:Cdrecord-Clone 2.01.01a04 (--) Copyright (C) 1995-2006 J=F6rg
:        3,0,0   300) 'PIONEER ' 'DVD-RW  DVR-109 ' '1.57' Removable CD-ROM
:2) What is the difference between cd0 and cd0c in the first place and why i=
:Dragonfly refusing to play an audio cd with cd0c, and yet writing data to i=
:thru K3B works?
:Some answers please...

    Well, my guess is that cd0c works when DragonFly thinks its a data CD
    and creates a fake partition table for it, so cd0c exists.

    I don't know why it thinks the burner does not exist when you specify
    the raw device (/dev/cd0).  /dev/cd0 should pass-through to the actual
    device.  Perhaps ktracing the two commands (with /dev/cd0 and /dev/cd0c)
    will tell us something.  We definitely want /dev/cd0 to operate for
    both audio and data from the burner's point of view.  For mounting
    purposes /dev/cd0a or /dev/cd0c may be required.

					Matthew Dillon 
					<dillon at>

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