Which does the term 'modern multikernel computers' refer to? Distributed systems or multi-core computers?
I saw it in a one-line question, so no context to help! Google didn't help neither.
Both. It's something like treating a multicore computer like a distributed system.
The Multikernel approach is described in this paper by Andrew Baumann et al.: The Multikernel: A new OS architecture for scalable multicore systems (published by the ACM, 2009). You'll find every possible information there, but here are the most important parts from the abstract.
First, why is there are need for something like this?
Then, what is multikernel?
Finally, you can even try it. Barrelfish is a multikernel operating system, released under the MIT open source license, created by the ETH Zürich and Microsoft.
Related to this, yet a bit earlier, also by Andrew Baumann et al.: Your computer is already a distributed system. Why isn’t your OS?.