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Comment by bregma | Hacker News Reader

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.

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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.

Amiga: https://wiki.amigaos.net/wiki/Introduction_to_Exec

> The Multitasking Executive, better known as Exec, is the heart of the Amiga's operating system.

> All other systems in the Amiga rely on it to control multitasking, to manage the message-based interprocess communications system, and to arbitrate access to system resources.

They can generally be run on bare metal, to my knowledge.

I personally don't remember exactly what was meant with "executive".

I've only ever heard of that as the type of a DOS/Windows .exe binary.

that's an executable...

There were publications in the 80s that used that term iirc, and I do recall the term for how slightly incongruous it was, and how it didn't come with an explanation.

In looking into ut some more, it looks like the executive was a term from mainframes for the layer of the kernel that enforced isolation, but I must have read the term being loosely used in pc magazines. Or maybe mockingly?

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