transport types define methods by which the environment document is communicated from the
deployment platform to the guest software.
To enable interoperability, this specification defines an "iso" transport type which all
implementations that support CD-ROM devices are required to support. The iso transport
communicates the environment 1346 document by making a dynamically generated ISO image
available to the guest software. To support the iso transport type, prior to booting a virtual
machine, an implementation shall make an ISO 9660 read-only disk image available as backing
for a disconnected CD-ROM. If the iso transport is selected for a VirtualHardwareSection, at
least one disconnected CD-ROM device shall be present in this section.
Support for the "iso" transport type is not a requirement for virtual hardware architectures
or guest 1351 operating systems which do not have CD-ROM device support.