Hey isolo,
The RPM files you see is the Virtual Appliance/VBA itself with rpm being the installation method we chose. We could have used an ISO, a Windows installer, etc., but we felt RPM was the cleanest, fastest method for ESX. When the VBA starts up and begins a backup, it is a completely self contained virtual appliance, meaning it is a virtual machine with a VMDK file, an installed operating system and a programed instruction set. Don't think it is much different than a NAT appliance, or a DHCP appliance, etc. There is a small piece of our application that does run in the console but that is mainly for scheduling and passing backup instructions to the VBA.
Pete@esxpress