User`s guide

Operations on Virtual Machines and Containers 81
 If you want to use an existing image file as a virtual CD/DVD-ROM drive, keep in mind
that Parallels Server Bare Metal supports .iso, .cue, .ccd and .dmg (non-compressed
and non-encrypted) image files.
 A virtual machine can have only one floppy disk drive.
 A virtual machine can have up to 16 virtual network adapters.
 A virtual machine can have up to four serial ports.
 A virtual machine can have up to three parallel ports.
 Any virtual machine can have only one sound device.
 A virtual machine can have only one USB controller.