Mounting CD inside VM fails first time after changing image

[Frans Pop]

I boot the installer using with the VM's CD pointing to an ISO CD image (CD1). During the installation I need to switch to a different image (CD2). Even if I do that procedure completely manually, the first mount command will always fail.

# umount /cdrom
/* use virtual disk manager to change CD ISO image */
# mount /dev/hdc /cdrom
mount: you must specify the filesystem type
# mount /dev/hdc /cdrom
mount: block device /dev/hdc is write-protected, mounting read-only
/* use virtual disk manager to change CD ISO image */
# mount /cdrom
mount: no medium found
# mount /cdrom
mount: block device /dev/hdc is write-protected, mounting read-only
# umount /cdrom

There is one strange thing: I can only reproduce this when using the Debian kernel compiled for a 486 processor (which is the one used in the Installer), not with the one compiled for a 686 processor. I can provide the kernel configs if needed.

I first experienced the problem during installation, but also reproduced it in an installed Debian system after booting it with the 486 kernel.

As this problem does not occur in vmware, I think it must be an issue in VirtualBox.

Context: Using a Debian Installer CD image to install a new system
Host system: Pentium D SMP x86_64 system running Linux 2.6.23
VM: VirtualBox 1.5.2 running 2.6.22 kernel

This report is based on my mail to the user list:
​http://vbox.innotek.de/pipermail/vbox-users/2007-October/002362.html

[Frans Pop]

The comment that the problem cannot be reproduced with a kernel compiled for a 686 processor is incorrect. I'm not sure why I could not reproduce it with that initially as I can reproduce it reliably now.

I've also tested that with a current 2.6.24 kernel the issue is still there, so it really looks like this is something in VirtualBox.

[Frank Mehnert]

Please reopen if this problem is still reproducible with VBox 3.1.6.