What kind of servers does Apple have in their NC datacenter? Siri telling me more often than not that it is having trouble connecting got me wondering what kind of servers Apple is filling its datacenters with. At some point in the past, I'd have assumed Xserves running OSX Server, but given that they are no longer making Xserves (or at least they are not commercially available), I can't help picturing pallets of Dell servers being unloaded and racked at the North Carolina datacenter.

Is Apple running its datacenter on Linux or Windows? Are they using standard PC hardware from Dell or IBM or HP? Or have they continued to manufacture Xserves for their own use and have everything running Lion Server?
I have read that Apple uses Microsoft Windows Azure and Amazon Web Services as at least part of their software platform for iCloud. Sounds like heresy, but there appears to be some evidence to support this.