I just want to unmount an ISO

[#1]

In Ubuntu I would just use unmount /dev/sr0 but I cannot see a way to do this in NIOS. 

[#2]

Hi, what is it you are trying to accomplish doing this? Using the NIOS hardware with a new OS on it? 

[#3]

The NIOS image was mounted to the VM in order to install the OS. Now it's installed, I want to remove the virtual disk from the VM but I have to unmount it in Ubunutu first.