't IsGoud

The next version of Virtual PC is released.

Important advice for those of you who already clicked the "download" button. Before you upgrade to Virtual PC 2007 make sure you have turned your virtual machines off.

Saved states are not compatible.

I uninstalled VPC 2004 SP1 and installed VPC 2007 and made the mistake of not reading the release notes. Well mistake, a link to the release notes, was only available after installing. ;-(

The first virtual machine I tried to open popped up a warning screen with the message: "Virtual PC was unable to registyer this virtual machine configuration file. The saved state assiciated with the virtual machine is not compatible ...".  If you happen to run into this screen and you have important changes in your saved state machine then there is still a fallback scenario:

1. Keep the Error dialog open.
2. Go to the directory with the files of your virtual machine.
3. Rename the .vsv file.
4. Open the virtual machine in Virtual PC 2004 SP1 and turn it off
   (You might have to reinstall Virtual PC 2004 SP1 for this step).

Another piece of good advice from the release notes:
ReInstall the "Virtual Machine Additions". That is uninstall the "Virtual Machine Additions" from the previous release and install the "Virtual Machine Additions" from the 2007 release. I haven't encountered problems yet but it is supposed to keep you out of trouble when you use "drag and  drop" between the virtual machine and the host.

New and improved in Virtual PC 2007:

• Support for x64 Windows as a host operating system.
• Support for hardware virtualization support.
• Support for Windows Vista as a guest and host operating system.
• Support for PXE network booting of virtual machines.
• Support for the use of fullscreen virtual machines on multi-monitor systems (VM still stays on just one monitor though).
• Improved performance compared to Virtual PC 2004.
• Improved support for use on Laptops.

For a recent project I needed to boot a machine with a specific UUID. I could not use Virtual PC because it had no support for it so I had to use VMWare. With this new version of Virtual PC this has changed. I compared the contents of the virtual machine configuration (.vmc) file and one of the new settings is the "bios_guid".
After creating a new virtual machine the settings are not yet available. Only after an initial run these settings appear in the .vmc file. This is the same in VMWare. Different though is the format of the GUID. VMWare uses an own syntax for storing the GUID while VPC uses the format as it is stored in the BIOS of a machine.

After the first test I found out that the bios_guid and the UUID from the BIOS are not exactly the same. The first half of the UUID found in the BIOS should be swapped pair wise in the .vmc file. I'm not sure what the reason is for this "swap", Big Endian, Little Endian conversion? Whatever. Just follow the swap scheme below and you're done .
The first line displays the UUID from the BIOS, the second line displays the bios_guid in the .vmc file.  

Overall I'm very pleased with this new PXE boot feature. Now I can stick to one virtualization application per platform. Parallels on my MacBook and Virtual PC on my Windows machine