VirtualBox: why there is no Passthrough checkbox on Storage screen?

[Warren Block]

On Tue, 30 Oct 2012, Bernhard Fröhlich wrote:

> On Mon, Oct 29, 2012 at 11:13 AM, Yuri <yuri at rawbw.com> wrote:
>> All conditions from section 23.3.3 are satisfied (atapicam is in kernel and
>> device permissions are right).
>> But storage screen only allows me to select some iso file to export into
>> guest. Passthrough checkbox never shows up on the Storage window.
>> For example, under IDE I see "IDE Primary Master", etc choices, it says
>> CD/DVD Drive but never offers passthrough (checkbox always stays invisible).
>>
>> How to understand why isn't passthrough available?
>>
>> DVD drive is recognized by system as:
>> cd0 at ata2 bus 0 scbus9 target 0 lun 0
>> cd0: <PIONEER DVD-RW  DVR-112D 1.21> Removable CD-ROM SCSI-0 device
>
> I've just verified it on my box and it just works. So it's hard to find out what
> the problem is. I remember that I had some problems in the past after updating
> the kernel but I did not recompile cdrtools or dvd+rw-tools which caused all the
> atapi commands to strangely fail when trying to burn a DVD. VirtualBox also
> uses that tools so I'd recommend that you just rebuild those two and check
> if it helps.

Try setting the VBOX_CDROM environment variable to the drive:

   setenv VBOX_CDROM /dev/cd0

or the sh(1) version:

   VBOX_CDROM=/dev/cd0