Server 2008: Windows System Image Manager and WDS

Windows System Image Manager, or SIM, is a tool that comes in the Windows Automated Installation Kit (AIK).

The AIK is not part of Windows Server 2008, but is a free download to any licensed user.

The one catch is that the AIK comes in the form of a DVD image which means to use any one part, you have to download the whole thing and then burn it to a DVD (or extract it somewhere else.) This is a slight pain, but probably better than trusting some website with the parts posted for download.

The good news is that the AIK has some other tools that come in handy as well. But, we’ll get to that later.

What is the Windows SIM?

The Windows SIM is a way to build and maintain answer files for use with Windows System Images (wmi files) or more specifically for taking WDS the rest of the way toward the promised land of easy automated installations of numerous types of systems.

While WDS handles all of the imaging using its clever PXE/TFTP structure, those images are still a long way from finished systems. That is where the answer files come in.

The old method for making an answer file was to sit down in front of a text editor and do your best to crank one out. Then, you would do an install with the answer file and wait for the inevitable errors to show up.

You would go back to your text editor, do all the fixes you thought you needed and try again. Obviously, this isn’t the best way to run a railroad.

With Windows SIM, you get a GUI interface to help you build your answer files. In and of itself, this is a great thing, but it is much more than that. Thanks to Windows SIM, you can take an answer file you are unfamiliar with, and instead of sifting through it line by line, you load it up and at a glance find the one or two values you need to change — make a couple of clicks, type a couple of values, and you have a new answer file ready to go.

But, the best thing about SIM is that it will validate your files without having to do any actual testing of an install. It isn’t perfect, but what it does do is bang your unattend.xml file against your setup packages.

If it detects missing parameters if flags those for your attention, so you don’t have to puzzle over why your install hangs at a certain point. It also will point out extra values that you don’t need which can help you determine if a component you want is missing.


Now, if you are thinking that you’ve seem Windows SIM before, you are right. As mentioned, SIM is not part of the Windows Server 2008 package the way WDS is.

Theoretically, you could use WDS without ever using SIM, though I wouldn’t recommend it. So, the key is to find where SIM fits into WDS.

Depending on your organization you may need to use SIM a lot more or a lot less than others. The more standard your systems are, the less you will need it. But, even with standards, it is likely that you have several kinds of systems running around your enterprise.

Those accounting computers have special programs that the engineering computers don’t and vice versa. Plus, most companies don’t have just one kind of accounting computer. There are the accountants who do billing, the ones who do modeling, and the ones who crunch the numbers for financial reporting, and so on.

Chances are each department breaks down further and further like this. With each subdivision, you might not only need additional operating level settings like an additional partition or drive map, but application settings as well.

What you really need is a way to use your images, but also handle various specialty applications and settings are dependent upon job function. To do that, you’ll use an unattend file.

Working with WDS

Basically, the way it will work is that WDS will incorporate your answer file into the image install process. So, the 30,000 foot view becomes, a system is booted to PXE, connects to TFTP/WDS Server, the base image is installed, and the linked answer file fills in all the gaps.

This requires one more piece of infrastructure — Distribution Shares.

Distribution shares are used to get the files that will be needed to add the additional software to the base image. A distribution share has three folders:

  • $OEM$ Folders,
  • Out-of-Box Drivers,
  • and Packages.

The $OEM$ Folder is where you put the software package you need installed, maybe QuickBooks or something like that.

Out-of-Box Drivers is where you put any third-party drivers that are needed. For example, maybe the driver for the scanner that the accountant uses to scan in invoices could be installed from the Out-of-Box Drivers folder.

Package is for actual packages from Microsoft. If your accounting PCs need an extra hotfix for whatever reason, that would go in the Packages folder.

Once your distribution shares are ready (and accessible from the computer you are installing) then it is necessary to link the answer file to the image within WDS.

To do that, log into the WDS Management console and find the image you are working with. Under properties select Allow Image to Install in Unattend Mode.

Once you do that, you can select the unattend file you want to use. Now, whenever a system comes looking for that image, it will also get the unattend file.

With that, we close in on the utopian "zero touch install."


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