I don&#x27;t technically have a horse in the unikernel race but have only been following the MirageOS team.<p>From what I understand unikernels or &quot;operating system as a library,&quot; are not not a new idea. The cost of implementing an entire TCP&#x2F;IP stack for every unikernel ecosystem is probably what kept them from being adopted early on. However we have some good specifications these days and battle-hardened implementations to test new ideas against. I think the idea behind MirageOS is that they see C&#x2F;glibc&#x2F;etc as a liability.<p>So building a TCP&#x2F;IP stack in a pure-functional language is an interesting idea. Just because we have a reliable system now doesn&#x27;t mean we can&#x27;t make it more robust by experimenting with new ideas.<p>One certainly needs to take more care building unikernel infrastructure than a typical web application or script. I&#x27;d only touch them in production with verifiable formal specifications and a strongly-typed functional language implementation... but that&#x27;s light-years ahead of what a typical gnu&#x2F;linux VM guarantees.<p>(Also the reason why I don&#x27;t think size will matter here is that they all aim to be pretty small and in a cloud, 42KB difference on HVs with &gt;64GB of RAM doesn&#x27;t make much of a difference)