Reza Alirezaei’s Blog

In part 2, we went through the process of creating a differencing drive based off a timebombed virtual image from Microsoft. Now, let’s look at what the value proposition of this process is. First, you have built a virtual machine that has a timer bomb in it. Second , instead of distributing the whole VM machine, you only distributed a much smaller differencing drive. You can tell others to download the MS base image, rename it to what you chose for the base image and place it in the same folder. Then ask them to create a new virtual machine and point to your differencing drive. That’s all! Let’s go through the step by step practice together:

1) Download my differencing drive from here. It is only 4.54 MB!

2) Unzip and place DhWSSDevDiff.vhd in a folder in your hard disk. For example “F:\Test\DhWSSDevDiff.vhd“. It is not important where you place it.

3) Download this MS image from the download center. I used this image, so you must use this one as well.

4) Unzip and place WSS.vhd in the same folder as DhWSSDevDiff.vhd.

5) Rename WSS.vhd to MsWSSBaseWithSP1.vhd. I used this name for my base image, so you must use the same name as well.

6) Create a virtual machine and point it to my differencing drive (DhWSSDevDiff.vhd).

7) Start your virtual machine. Once you login, your desktop looks like the below picture.

8 ) Great! Now ,you have learned how to ship your functionalities in a diff drive protected by Microsoft EULA and timer bomb in the base image– Thanks MS!

Like any other workaround, this has its own demerits:

1. You are locked down to the expiration dates MS places on their images. As I alluded to in part 1,  there is going to be at least one SharePoint images available to use in this process until Sep 2009.
2. You have to use the correct base image, otherwise this doesn’t work. Using the same base image is a very important step!
3. There is a point of no return when using differing drives. If for any reasons base image needs to be updated, you need to rebuild the differencing drive and redistribute it. You can’t expect those changes to be propagated to your differencing drives automatically. An image that is used as the base for differencing drives must be sealed (Make It Read only). Changes to the base image will cause unexpected behaviors in the derived vhds if they are not rebuilt.
4. The point of no return is also true about the base image. If you need to retimebomb it, you need to to build and redistribute your differencing drive again.

I still have to verify when the counter starts. From when you built your diff drive or from when your customer attaches your diff drive to their base trial image? Either case , they have 30 days maximum to play with the virtual machine and they can’t use the machine when the current date > VM drop dead expiration date (Septemberish!).

If you are downloading my diff drive available here one month after the date of this blog post ( the same date I built the diff drive) and following the steps above and you see the time bomb gets activated , please leave me a comment here and let me know that the bomb was exploded properly.

In case you need to add a prelogin image to your timebombed VM providing your users with login and other useful information, just create a BMP image and store it somewhere. Then fire up regedit and put the full path in HKEY_USERS\.DEFAULT\Control Panel\Desktop\Wallpaper key:

And here is the end result: