The virtual CD/DVD drive(s) by default support only reading. The medium configuration is changeable at runtime. You can select between three options to provide the medium data:
-
Host Drive defines that the guest can read from the medium in the host drive.
-
Image file (typically an ISO file) gives the guest read-only access to the data in the image.
-
Empty stands for a drive without an inserted medium.
Changing between the above, or changing a medium in the host drive that is accessed by a machine, or changing an image file will signal a medium change to the guest operating system, which can then react to the change (e.g. by starting an installation program).
Medium changes can be prevented by the guest, and VirtualBox reflects that by locking the host drive if appropriate. You can force a medium removal in such situations via the VirtualBox GUI or the VBoxManage command line tool. Effectively this is the equivalent of the emergency eject which many CD/DVD drives provide, with all associated side effects: the guest OS can issue error messages, just like on real hardware, and guest applications may misbehave. Use this with caution.
Note
The identification string of the drive provided to the guest (which, in the guest, would be displayed by configuration tools such as the Windows Device Manager) is always "VBOX CD-ROM", irrespective of the current configuration of the virtual drive. This is to prevent hardware detection from being triggered in the guest operating system every time the configuration is changed.
The standard CD/DVD emulation allows for reading standard data CD and DVD formats only. As an experimental feature, for additional capabilities, it is possible to give the guest direct access to the CD/DVD host drive by enabling "passthrough" mode. Depending on the host hardware, this may enable three things to work, potentially:
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CD/DVD writing from within the guest, if the host DVD drive is a CD/DVD writer;
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playing audio CDs;
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playing encrypted DVDs.
There is a "Passthrough" checkbox in the GUI dialog for configuring
the media attached to a storage controller, or you can use the
--passthrough option with
VBoxManage storageattach; see Section 8.18, “VBoxManage storageattach” for details.
Even if pass-through is enabled, unsafe commands, such as updating the drive firmware, will be blocked. Video CD formats are never supported, not even in passthrough mode, and cannot be played from a virtual machine.
On Solaris hosts, pass-through requires running VirtualBox with real root permissions due to security measures enforced by the host.