It's worth pointing out that we've written vast amounts of OCaml in Xen/XenServer from about 2005 (now used in lots of public cloud installations like Rackspace

It's worth pointing out that we've written vast amounts of OCaml in Xen/XenServer from about 2005 (now used in lots of public cloud installations like Rackspace), and much of this choice was inspired by Richard's blogging/code to show how it could be done. OCaml is almost 20 years old now, which is about the right amount of time to start trusting a language for mission critical code :) Some of our experiences in Xen that we wrote up for ICFP 2010: http://anil.recoil.org/papers/2010-icfp-xen.pdf http://anil.recoil.org/papers/2010-icfp-xen.pdf And lots of source code: https://github.com/xapi-project https://github.com/xapi-project https://github.com/mirage https://github.com/mirage