PHPVirtualbox install OS forbiden

annot open host device '/dev/sr0' for readonly access. Check the permissions of that device ('/bin/ls -l /dev/sr0'): Most probably you need to be member of the device group. Make sure that you logout/login after changing the group settings of the current user (VERR_ACCESS_DENIED)

Following the instructions, I see the following:

[root@desktop ~]# /bin/ls -l /dev/sr0
brw-rw----. 1 root cdrom 11, 0 Nov 18 10:30 /dev/sr0

I understand how Linux files have user permissions. Do devices have something similar? How are permissions on devices viewed and modified?

hat phrase is a classic adage in the Linux world and it is meant to be taken quite literally. In the Linux world, (almost) everything is a file. This includes pipes, directories and devices. So, the way of changing permissions for a device is the same as doing so for any other file:

# ls -l /dev/sr0
brw-rw---T+ 1 root cdrom 11, 0 Nov 18 14:55 /dev/sr0
# chmod a+rw /dev/sr0
# ls -l /dev/sr0 
brw-rw-rwT+ 1 root cdrom 11, 0 Nov 18 14:55 /dev/sr0