Simply have a boot manager that will allow you to select a partition to boot from. Windows installation is notoriously strong in overwriting things like the MBR on the HD, and at times clobbering the MBR to the point where it can’t be used for boot purposes. I have heard folks doing things like seperate installations on seperate drives, then mirroring them over to the target drive (whatever partition you desire), and also paying attention the installation sequence, one windows installation may be more prone to munge the entire installation (read MBR damaged or such).
Here are some links from googling…
and finally to answer best practice on this one… Its a good question. The goal is to make reimaging easy, so you can quickly refresh/mirror at the end of each test cycle or sequence. If you are limited to hardware, and can’t afford or justify the 3 systems or VMs in question, you then may want to just do a triple OS installation on a multiple partitioned drive and call it good. One problem with this approach is that you can’t fire off another test sequence while the drive mirroring/refresh is going on. So, my gut feeling is either to do the following:
3 drive system, with 3 OS install one per…
1 drive system (large, 200-300 gig maybe), 3+ partitions, 3 OS install.
Multi Host SUTs, each with 1 drive each…
Virtual Machine with VMWare or Citrix and state save/mirror and be done with all this about drives, systems and hardware
My desire is to pick #4, for obvious reasons. The pros and cons you can figure out and have to fit into your environment. Remember, snapshots are not instant and are not free. They take time just like anything else to come up to speed/run. They are great for a lot of reasons, but take drive space too, and versioning can be very costly in this realm (depending on your SUT configuration requirements).
There is a lot to think about, and you can try some of these things out in pre production with VMWare and Citrix, and Parallels if you want to run the Windows stuff on Intel hardware (which a lot of people do with XServers).
Let us know what you find out, and think is going to meet your particular needs, of which surely its a moving target and changes daily. Other’s input here is very welcome, and I hope more people start sharing their VM solutions, what works and doesn’t (maybe a new topic would be in order for the forums).