Quote Originally Posted by johnc View Post
There is a lot of open source software on Windows.

The fact that Intel seems to have two separate drivers and two separate driver teams that probably don't communicate is indicative of some other reasoning. Why not just have a unified driver like NVIDIA and AMD?
But still, opening stuff has a cost, you need a legal team to review the whole stuff, possibly redo internally (with clean room) some bits that you bough to a third party, or even possibly, some technology of a startup you bought that you don't own fully, etc...
Against that, you have gains: you can use open source tools for your driver, other corporations and individuals will be working for you, you can influence the whole platform if it's open too, the kernel/OS developers can work with your stuff more easily, etc..

For the windows platform, most of these gains don't exist: there are no open source tools or kernel to build upon, and development is centralized. And if you want OS devs to work/debug with you, they all will be professional Microsoft employee, so you can give them NDA + sources or debug dlls, that won't have all the hurdles of public distribution.

So it's quite possible that costs/benefits balance in one direction on Linux and the other on Windows... If their code base is small enough of "non-legacy" enough, it makes sense for them to develop two drivers, each best adapted to its environment.