Of course that was a study for a unrealistic situation. I quickread through the document, and it discussed a server park (web services), without saying anything about a backup solution, high availability, etc. Usually, SLAs will mention availability and maximum restore times.

I don't want to dismiss the document, but I do want to stress out to not use it to generalize. It does discuss TCO of a specific setup - and can't be taken as a general comparison between Linux, Windows and Solaris (I doubt that's even possible).

Abigail