GMail running Solaris 8?

According to Netcraft, GMail is alternating between Linux and Solaris 8?
Netcraft - Google running Solaris 8?
I always read and heard that Google runs Linux exclusively on their huge cluster. (here’s another link)
So I wonder if…:

  • …Netcraft is determining the operating system incorrectly
  • …Google is actually using Solaris 8 on some of their machines in the cluster
  • …Google is using a few systems with Solaris as a “gateway” to their Linux cluster
  • …I am the first person to notice this outside of Google. (Or at least the first to create a blog entry about it.)

Maybe we will hear something official. Or if there has been some kind of information released by Google regarding Solaris 8, please add a link to it within the comments.

P.S. – If you were wondering what GFE/1.3 is, it is Google’s web server software, which is rumored by some people to stand for Google Front End (version 1.3).