They seem to spin up (reuse?) an entire instance for each request There are some clever platforms running on bare Xen (no direct OS) that can spin up an entire

They seem to spin up (reuse?) an entire instance for each request There are some clever platforms running on bare Xen (no direct OS) that can spin up an entire instance and destroy it on every request pretty quickly. http://erlangonxen.org http://erlangonxen.org is a great example. 100ms to boot your entire "system" for production usage.