Most of us have now submitted entries for validation, and a portion of us have seen our apps fail validation for what are common mistakes.

These errors and omissions can be easily avoided if we simulate the validation environment prior to submitting our entry. Enter VMWPlayer, the free virtualization offering from VMWare. With a virtual environment, we can not only simulate the vanilla OS, but reset the state back for subsequent tests. Below you will find a very simple tutorial on getting started. The following applies to any Windows OS, with an emphasis in this document on Windows XP.

Step 1 Install VMPlayer

Head on over to http:// and get the free version of VMPlayer here: http://www.vmware.com/products/player/. Once downloaded, install using default settings.

* Note: By default, this product is fairly basic, with no built in feature to create new VMWare Images. See the next step for the solution to that.

Step 2 Create your new virtual disk with Qemu

Now we need to create a virtual image (or disk) to nistall our test OS onto. Thankfully this is a simple task thanks to a utility called Qemu.

Download and Install Qemu: http://wiki.qemu.org/Download

Once installed, open a command prompt and execute the following command to create your virtual disk:

C:\Program Files\Qemu>qemu-img.exe create -f vmdk ATOM_Test_Disk.vmdk 4G

Now we have a 4 GB disk to work with.

Step 3 Configure Virtual Disk

We need to let VMPlayer know what kind of disk this will be and what settings to use. This is as simple as creating a plain text VMX file with the same name as used above (ATOM_Test_Disk). Open up your favorite text editor and create ATOM_Test_Disk.vmx, Paste in the following:

config.version = "8"
virtualHW.version = "3"
ide0:0.present = "TRUE"
ide0:0.filename = "ATOM_Test_Disk.vmdk"
memsize = "256"
MemAllowAutoScaleDown = "FALSE"
ide1:0.present = "TRUE"
ide1:0.fileName = "auto detect"
ide1:0.deviceType = "cdrom-raw"
ide1:0.autodetect = "TRUE"
floppy0.present = "FALSE"
ethernet0.present = "TRUE"
usb.present = "TRUE"
sound.present = "TRUE"
sound.virtualDev = "es1371"
displayName = "ATOM Test Environment"
guestOS = "winXPPro"
nvram = "ATOM_Test_Disk.nvram"
MemTrimRate = "-1"m"
MemTrimRate = "-1"

ide0:0.redo = ""
ethernet0.addressType = "generated"
uuid.location = "56 4d 5c cc 3d 4a 43 29-55 89 5c 28 1e 7e 06 58"
uuid.bios = "56 4d 5c cc 3d 4a 43 29-55 89 5c 28 1e 7e 06 58"
ethernet0.generatedAddress = "00:0c:29:7e:06:58"
ethernet0.generatedAddressOffset = "0"

tools.syncTime = "TRUE"
ide1:0.startConnected = "TRUE"

uuid.action = "create"

checkpoint.vmState = ""

* Note: As you can see, there are many variables to work with above. A quick Google on VMX file format will give you many options.

Step 4 Installing your OS

Well, now we need an Operating System. For simplicity we will install Windows XP. This may be the easiest part so far.

Simply insert your Windows XP CD into your computer, then double click on the ATOM_Test_Disk.vmx you created in Step 3. VMPlayer will boot from your installation CD. Proceed through the installation process then remove the CD.

Step 5 Getting ready for ATOM Testing

Now is a good time to back up your "master copy" of your new virtual environment. Simply copy your VMDK and VMX files to a safe location.

We want to emulate what the testers will be doing when validating our entry right?

Well, we know they have Windows XP SP3, so go ahead and download and install onto your new virtual environment.

* Note: DO NOT install the CRT (C++) Runtime. This is critical as the MSI installer for your ATOM entry must provide this automatically.

Now each time you would like a clean test environment, you can be ready in minutes. I recommend you create a set of validation tests such as checking for the creation of a desktop icon, application launch, etc. Best of luck in your ATOM application testing!