&gt; A DNS service built with IncludeOS results in a 158K disk image (for comparison, the MirageOS DNS server image came in at 200K).<p>A 42K difference and OCaml buys you memory safety and the ability to embed an invariant in your type system; further restricting the allowable executions of your program.<p>That is the point of MirageOS. They chose a functional language because they wanted a trusted computing base (or something as practically close to trusted as one can get).<p>I don&#x27;t think <i>size</i> is going to be the big determining factor for people choosing competing unikernel implementations.