Comment by bregma

1 month ago

So, if I understand correctly, a "unikernel" is what we used to call an "executive" except it is intended to be run as a guest on a virtual machine provided by a full-fledged traditional kernel/userspace OS instead of on bare metal.

The article does reintroduce some concepts that were commonplace when I was first learning computers and it gives them some new names. I like that good ideas can still be useful after years of not being the latest fad, and it's great that someone can get new credit for an old idea with just a little bit of marketing spin.

There is no need in the operating system to run Unikernels. Every Unikernel includes parts of operating system needed for interacting with the underlying hardware. So Unikernels can run on bare metal if they know how to interact with the underlying hardware (i.e. if they have drivers for that hardware). Usually Unikernels are targeted to run on virtual machines because virtual machines have unified virtualised hardware. This allows running the same Unikernel on virtual machines across multiple cloud providers, since they have similar virtual hardware.