Being someone who has to use a mix of OSes in a heterogeneous (and I guess that's the case for a lot of people here), I deal mostly with FAT32 partitions as host systems, because it make life easier (think of a VM that has to go from Windows to Linux to OS X on an external HD). It's been fine for a while with multiple 4GB partitions (and enforces good practices as separating the OS from the data or from the swap), but today, some OSes (Vista, some bloated but nonetheless useful Linuxes) just won't install on such 'small' partitions. I'd like a feature (and I don't think it is a feature that would take time to implement) which automatically spans the .hdd in as many files of an arbitrary size as needed (say vista.000.hdd, vista.001.hdd, vista002.hdd and vista003.hdd and voilà , a 16 GB partition). I know some people will tell me that FAT32 is outdated, useless, etc., but in the case of virtual hard disk, it's just not true: its inherent simplicity makes it very compatible and really quick to use as a virtual hard disc container. There's no use for a complex host filesystem as ReiserFS or NTFS for files that contain their own filesystem, with journaling and all. In fact it only makes the emulation slower. As for fragmentation of the host file, that is _not_ an issue if you work with plain (non sparse) hdd images. Defragment it once so that the four or so files are contiguous and you're done. So please, Parallels team, consider this for your next build
