kern/115232: [ata] Audio CD tracks not displayed properly by atapi driver

Oliver Fromme olli at
Tue Aug 10 10:28:40 UTC 2010

Yuri <yuri at> wrote:
 > Could you check if:
 > > # dd if=/dev/acd0 of=/dev/null count=1
 > > 
 > > does the trick as mentioned in the Handbook?
 > > 
 > > 
 > >
 > Yes, this trick works.
 > But the problem with it is that this should be done without such 'dd'
 > command. User should be relieved from issuing such meaningless command

It's not meaningless.  It causes the driver to actually
look at the drive, re-read the TOC of the CD (there is no
other way to find out if the CD was changed) and update
the device nodes in /dev.

 > since system can do this automatically, avoiding user actions and
 > possible user confusion.
 > Driver knows when disk is inserted

No, the driver does *not* know when a disk is inserted,
unless it actually accesses the CD (caused by the "dd"
command above, for example).

Automatic detection and notification is not supported by
the hardware (unlike USB devices, for example).

 > (for example in Windows autorun executes when disk is inserted).

That only works because Windows actively polls the drives
periodically, which is a bad hack, in my opinion.

Best regards

Oliver Fromme, secnetix GmbH & Co. KG, Marktplatz 29, 85567 Grafing b. M.
Handelsregister: Registergericht Muenchen, HRA 74606,  Geschäftsfuehrung:
secnetix Verwaltungsgesellsch. mbH, Handelsregister: Registergericht Mün-
chen, HRB 125758,  Geschäftsführer: Maik Bachmann, Olaf Erb, Ralf Gebhart

FreeBSD-Dienstleistungen, -Produkte und mehr:

$ dd if=/dev/urandom count=1
$ file perl script text executable

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