I use Microsoft (formerly
Connectix) Virtual PC to test servers etc, and I find it very useful to have a
handfull of different OS's pre-installed into VPC. To speed things up even more,
you can use the disk differencing feature.
Disk Differencing works by
storing only the changes to an original image in a new VPC virtual hard-disk. So
in ASCII:
VPC Image:
________________________
|
|
| OS
VHD |
|
|
|_______________________|
Differencing VHD:
_ _ _ _ _ _ _
| |
| Changes |
| |
|_ _ _ _ _ _ _|
This allows you to then have
multiple VM's on your machine using only one parent VHD.
This is how its done:
1. Create a new Virtual Hard
Disk using the Wizard
2. Create the differencing VHD
in a folder of your choice. (This is the disk that will hold the changes made to
the parent)
3. Select Differencing hard
disk
4. Then select the Parent VHD.
(The one with the OS installed on it)
TIP: Always mark your parent hard disk “Read Only“ as to prevent making accidental changes to it. If you do make changes; it can cause all sorts of problems with your VPC's based off that parent. (Thanks to John
Howard for
this tip!)
5. And you're done creating
the disks.
6. Now create a New Virtual PC
to host the Virtual disks
7. Choose a folder and a name
for the VPC
8. Select an OS from the list and assign it memory; then select to use an existing disk.
9. Select the differencing disk you created in step 2. (You can
enable undo disks too; but that will degrade performance and use up even more
hard drive space)
10. You're done.
