Vista VM Disk Size < 12Gb

I recently installed Vista in a VM on my Linux virtualization platform, running Qemu/KVM. Today, I installed a Vinat on a VM on my Vista laptopn, running Microsoft Virtual PC 2007. As part of the experiment, I wanted to how small I could make the virtual disk. On my Linux platform, I gave Vista 20 gigabytes, and was disappointed to find that it took about 12GB of space.

This time, I gave it 10GB, expecting to get an error, and found that it installed on about 7GB, This seems to imply that Vista, which no long prompts for "what do you want to install" makes these decisions for you based upon the space it sees. By giving it less space, it put less crap on the drive. I was able to clean about another 500MB by deleting Games and few other silly things.

Unfortunately, the VM would not install SP1 from disk, as it needed 4GB to extract. By adding a second virtual drive of 5GB as a "D Drive", SP1 was able to install. I actually removed the second drive once loaded. Thus, it looks like it could be possible to run Vista on 8GB, but 12GB seems to be the base.

*** Update 8/12/2009 ***
Using a second disk was too unstable. After installing SP1 and a dozen security patches, the 8GB disk reached capacity. and the VM would lock up. There was no easy way to shift components from the C: drive to D:. I ended up rebuilding at 12GB, and after updates have 3GB left-- acceptable for small testing tasks.