Microsoft Virtual PC defaults the hard disks for it’s virtual machines to 16 gig in size. For most instances that’s large enough, but you could have cases where you simply need more disk space. Or, perhaps you’d like to keep your demo or project code in a separate virtual hard disk than the main virtual disk your applications run on. Regardless of your reason, creating a second hard drive for your virtual machine is fairly easy.

A few up front points, in these instructions I’ll be doing what I believe to be the most common scenario for most folks and be using Windows XP for my guest system.

First, before you launch your Virtual PC click on it once and select the settings button. Now go to Hard Disk 2. Change the option button from “None” to “Virtual hard disk file”. Next, click on Virtual Disk Wizard.

The first screen is simply the welcome screen, just click next.

On the next screen it asks about disk options. Take the default of “Crate a new virtual disk” and click next.

You are now asked about what type of disk you’d like to create, a hard or floppy disk. Take the default of “A virtual hard disk” and click next.

Now you are prompted for the name and location. I stored this with my other VHD files, so enter the path and location you want and click next.

The next screen asks what type of drive you want to select. The default, “Dynamically expanding” is the default, and is what we’ll be using. This is a great option as it puts a small file on your drive and lets it slowly expand as you need it to grow.

“Fixed size” creates just what it sounds like, a fixed size hard disk. The one main use I could think of is to create a virtual disk the same size as a DVD. You can then store your files on it prior to burning to a DVD. Downside is that the drive always takes the same amount of disk space.

“Differencing” is a big topic, but in brief a differencing drive is based on another VHD file. Once you create a differencing drive, the original is locked and cannot be changed; all changes are written to the differencing disk. Why would you want to do this?

Well let’s say you were teaching a class and wanted to let the students work on labs. You’d create your base image with your software loaded, and then create a differencing disk. Your students would write their changes to the differencing disk. After that class was done all you have to do is create a new differencing disk instead of having to recreate your entire disk image.

Final is linked to a hard disk. It saves your info out to the real hard drive. This is considered an advanced option, and to be honest I haven’t experimented much with it so that’s all I’ll say for now.

As I said, we’ll go with the default for now, and pick “Dynamically expanding”. Click Next to continue.

Next we are prompted for the maximum size of the VHD. In this demo we’ll take the default of 16 gig and click next, however if you’d like to change it go ahead, enter the maximum number of megabytes you want, when you’re done click Next.

OK, you’re up to the final screen, this just asks you to confirm your choices. Click on Finish to complete the process.

You should see a small message saying you’ve created the disk. Just click Close to close this message.

Now that you’ve created your drive, you need to tell Virtual PC to use it. If you recall, in the settings window we’ve already selected the “Virtual hard disk file” option. Now click the Browse button and pick the vhd file we just created.

OK, now we’ve got Virtual PC all setup. Click on OK to close the settings, then click on Start to start the Virtual PC. Once you’ve logged in, open up a My Computer window. Here’s a snapshot of mine.

OK, I can hear you now. “Hey, I created another drive, where’d it go?” Well, it’s there, the problem is you haven’t formatted it yet so Windows XP doesn’t know what to do with it. Let’s fix that now.

Open up Control Panel, and go into Administrative Tools. Now double click on Computer Management. Now click on Disk Management under Storage in the tree. The minute you do, you’ll be presented with the “Initialize and Convert Disk Wizard”. After taking a look at the opening screen, click Next.

The next screen asks which disks you want to convert. Here, you see Disk 1 is selected, which is correct (your C drive is disk 0, then each additional drive is 1, 2, etc.) Click Next.

Now it asks about converting disks to Dynamic disks. Check this on, and pick next. (Note in the pic below I haven’t checked it on yet, you will need to.)

Finally, you are presented with the Finish window. Click Finish to complete.

Now the window shows Disk 1 as initialized, but it’s still not quite ready to use yet.

Hang on, we’re almost done. Right click in the Disk 1 area, and select New Volume. This launches the New Volume wizard. On the opening screen just click Next.

Now you are presented with the Select Volume Type. Simple is the only option enabled, so let’s just select Next.

The next screen is prompting you to see how much disk space you want to allocate to this new volume. In our case we’ll use all the space, so we’ll just click Next.

In the next dialog we’re asked what drive letter to assign to our new volume. You can pick any available letter, but I think I’ll just take the default of E and click Next.

Now the wizard will prompt about formatting. We need to format this drive, so we definitely want to do this. I did change the default volume label from “New Volume Label” to “VSDriveE” since I’m using this with a vhd I use for Visual Studio. However, you should name it something appropriate to your use. Other than that, I’m leaving the other options alone and clicking Next.

Finally we’re nearing the end. The next screen is the “Completing the New Volume” wizard. Here we are simply confirming our choices. Take a quick look, if all looks well, click Finish.

While it formats, it will show you the progress in the status window, as you see below.

OK, that’s it, you’re done. Close the Computer Management window, then the Administrative Tools window. When you return you new computer, you will see your new drive, ready to go!

Well there you go. Seems like a lot of steps, but it took a lot longer for you to read this than it will take you to actually do it. If you do create new drives, drop a comment and let us know what creative uses you use your second drive for.