Et Al: (Hoping this hasn't been posted twice by myself.)

Instead of using Time Machine for this, I want to backup my iTunes epubs and audiobooks into a dmg file (Books.dmg) on a usb stick (MEDIA LIB 1).

Using Disk Utility I created Books.dmg with read/write properties.

I am working tediously (newbie at this) with Applescript to check the modificaton dates on Books.dmg as well as the epubs in iTunes. If the epub has a date later than the one for Books.dmg, this would add that epub into the appropriate Author folder in Books.dmg.

Now, I know i refer to a folder (in Applescript-speak) as folder "Books". What do I use for MEDIA LIB 1 and Books.dmg?

I have tried things like volume, disk image, folder, and some others, to no avail.

How do i refer to them?