Why did Windows 7 pick THAT driver ?


Today I stumbled against the following Blog. Which perfectly answers one important question of my (and my customers) .

“How do make Windows pick the correct driver?”

The secret behind this is called ranking, ranking occurs when drivers are added to the driver store and that happens of course when we deploy a new Windows 7 machine and drivers are injected. When using MDT in a LiteTouch configuration, the LiteTouch script will do a Plug and Play scanning of the hardware and the use the information the get the correct drivers from the MDT out-of box drivers folder. Now, MDT cant really “know” if that particular driver is the perfect driver so it will copy all drivers to the \Drivers folder on the machine to be deployed. But if you use Driver Groups or any other method that will “filter” the drivers the script would then only copy the one and only driver need.

Well that’s in the perfect word and since that does not exist we will get multiple drivers copied down to the \Drivers folder and then when MDT (using DISM in a offline mode) pushes those drivers into the OS there will be scenarios when we are going to have drivers that have the same PNP number and Windows must choose the correct one and now its time for ranking. In the best of worlds, when all the vendors created perfect drivers and everyone is always running the latest and the greatest this would not be a problem. But in the reality not all vendors have a perfect .inf file, in fact some of them are uglier then others and they does not even work.

Before we go into details on how that work, you might want to know how to “see” this, well that is not a secret there is of course a log file for that and the logical name for that is c:\Windows\inf\setupapi.dev.log and here is a sample where it just happens to be two drivers to pick from: (This log files has been modified and shortened just to show you)

Original and full Source: http://deploymentbunny.com/2011/06/06/nice-to-know-why-did-windows-7-pick-that-driver/


About arnepeleman

I am a system center enthusiast, IT Geek. View all posts by arnepeleman

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