Not entirely the case. Just like the OS on a physical disk takes longer to seek for fragmented files, it still takes longer to seek fragmented files within a virtual disk (which resides on a large portion of a physical disk).
That's true, but I don't think the Windows defragger actually moves any files or directory entries within the virtual container file. It's my understanding that the Parallels hypervisor abstracts file I/O from Windows to such an extent that when the Windows defragger attempts to move a file, the Parallels hypervisor merely discards those commands without changing anything inside the container. I might be wrong about that, but I seem to recall reading that that's the case--if you look at the container file before and after running a Windows defrag program, the container file hasn't changed.
