Hello, all. I've recently learned that you can virtualize an existing OS on your host hardware within Sun VirtualBox. I have two internal HDDs: one with Ubuntu on it (currently my "main" OS), and one with Windows XP on it. I was wondering if anyone could point me to a guide on how to set up the Windows drive in VB, and if this would be risky or not. All I know in that regard is to not install Guest Additions, because that would probably blow my driver setup all to hell on that drive.

I have VirtualBox 3.0.6 (non-OSE), and I currently have only one VM set up in it (a Slackware install, just to see what all the fuss is about. It seems that a lot of LQ users are running some version of Slack ).

One main concern I do have is whether VB will screw with the MBR on any of the drives...I don't want to take any chances with that, and I'm hoping there's a safe way to use the Windows drive with VB that doesn't involve messing with (or, god forbid, erasing) the MBR.

Have a read of the user guide, "Advanced Topics" - especially the warning in the text-box. Fixing an MBR is the most trivial of data recovery.
Personally I don't use raw disks in guests.

Thanks for the reply. I took a look at the user guide, and I guess this is something I should only do if I'm willing to back the Windows drive up first. The main reason I asked is because I think it would be convenient to be able to run my Windows environment without rebooting, and without having to purchase another copy of Windows to install in VB (which would be kinda pointless anyway, because then I wouldn't be able to access my stuff on the physical Windows drive). I would make a VDI out of my existing HDD, but I think that would be illegal according to the Windows EULA...right? I've heard how the Windows EULA is infamously restrictive, but I don't know exactly how far it goes...I've never looked at it, I just skipped it right along during the install process when I was setting up again for like, the 3rd time in a row...

AFAIK, virtual HDDs can be configured as real HDDs, real partitions or files on the host file system.

I understand you want to run ubuntu as the host and WXP as the guest and you are wondering about license issues and using the existing WXP file system(s) (on one HDD) without the need for re-installing WXP.

It has been said that the EULA does not permit this. That seems unreasonable; the license is tied to the hardware (thanks, Microsoft -- that's really convenient ) and you are running it on the hardware. It has been reported:

• When Microsoft have been asked to unlock WXP on virtual hardware when the same license key is already registered with real hardware, they have done so, in what appears to be breach of their own EULA.
• WXP installations into virtual machines using license keys already registered with real hardware do not prompt for re-registration.

As you have already concluded, modifying your existing WXP HDD's file system(s) to run in a virtual machine would stop them being useful on the real hardware. The reasons for this are not so much MBR changes (which may not matter at all) as much as the apparent hardware changing drastically and consequent changes in WXP to suit resulting in i no longer being matched to the real harware. More details on the link below. WXP in a virtual machine without Guest Additions is usable but it's a lot nicer with them.

If you do want to install WXP in a virtual machine from your existing real WXP HDD, then AFAIK this is the way to do it. It ain't easy and nobody has reported here about doing it (successfully or unsuccessfully):

1. Image your existing WXP HDD.
2. Define a virtual machine for WXP including a virtual HDD at least as large as your imaged HDD.
3. Boot the imaging program (from .iso or actual CD-or-DVD) in the virtual machine.
4. Restore the backed up HDD image to the virtual HDD.

Now the real work would begin, to modify the contents of the virtual HDD to suit its new virtual environment. See the instructions at virtualbox.org.

All in all it's probably easier to do a new installation in the virtual machine and, anyway, WXP often benefits from being re-installed.