This thread was very helpful: > Explain this to me then: What's the difference, conceptually, between (A) a VM host running a unikernel capable of solving one

This thread was very helpful: > Explain this to me then: What's the difference, conceptually, between (A) a VM host running a unikernel capable of solving one particular kind of problem, and (B) an OS running on bare metal running a process capable of solving one particular kind of problem? They are very similar. The main difference is the shape of the OS APIs. In the former scenario, the host provides things that look like CPUs, NICs and things that look like block devices, with no high-level abstractions (e.g. threads, sockets, and filesystems). If these are needed, then the unikernel will link in device libraries that provide them. In contrast, in the later situation the OS will be providing these even when they are not needed and they will add overhead to those code paths. Additionally, the amount of process state owned by the OS is far greater in the latter case. Things like file descriptors, thread priorities and so on make it far harder to snapshot or migrate an OS process. Hypervisor interfaces tend to be as close to stateless as possible.