> What are you saying? That Microsoft can't build a consumer OS with great power-management because the kernel also needs to work on high throughput servers?
It's more the drivers than the kernel. Apple has a lot more control over OS X drivers.
Right, but the original post said the same about Linux.
With very few exceptions, Linux drivers live in the kernel tree, so the Linux community has absolute control over them. The claim doesn't really seem to make sense. It's not like power management is unimportant in a server rack.
In fact, there's a really nice talk somewhere by (I think) the LWN guy, about how running the same kernel on mobile and on big iron gives huge benefits to development -- it turns out that the needs are really not so different after all, and power management work intended for the mobile space helps big iron (and vice versa, cf. PowerTop from Intel).
Nothing is free - everything is a trade off. Hardware isn't magical. There is cost to how fast you can switch between various C states on Intel CPUs for example. There is hardware that explodes if you play too hard for another example. Servers need maximum performance and low latency - guess what aggressive power management will do to that?
You talk about drivers but what about firmware? Have you looked at how kludgy and unreliable ACPI implementations across hardware are? What about the in kernel drivers being mostly reverse engineered - how many hardware vendors care to provide power management docs for their hardware?
Everything is possible of course - it's just that it is way harder to do when you support everything from toasters to big iron in case of Linux and Phones to gazillion varying PC hardware combinations in case of Microsoft.
It's more the drivers than the kernel. Apple has a lot more control over OS X drivers.