I'm not familiar with VirtualDisk. I found this: COMPAREX - INFINISTORE VirtualDisk on the internet. Is that what you're using?
VirtualDisk is a Windows-Application to mount Images in a virtual CD/DVD-Drive and use it like a regular Disk.
You can even provide those virtual Disks over the network.
You don't need any special software under Linux to archive your DVD's and play them off the hard drive. The way Pluto does it is to use 'dd' to backup the DVD a single file containing a byte-for-byte copy, and then 'mount' it when you want to watch it.
I am not that familiar with linux. I only looked for a standard-application like the one for Windows. I did not know, that there is a built-in - feature like "dd". How does it look like, when I want to mount a certain ISO-File ?
How many Images can Pluto handle ?
I'm not sure how VirtualDisk does it and if the file format is compatible.
The format of my Images is .ISO and .IMG. They are stored on an external Disk-Array and connected via Serial-ATA to my Server.