Reading Notes: an operating system for multicore and clouds

Some of my reading notes for the paper "An operating system for multicore and clouds: mechanisms and implementation"

Things I liked and that were interesting

It was interesting to learn that in future manycore systems the number of cores will exceed the number of processes. In connection with this the authors say that it is necessary to do space multiplexing instead of time multiplexing. I think this is a very big shift in thinking about computing power, as one has to think about how to map cores to processes, instead of time slicing one CPU to achieve multi-tasking.
It was also interesting that the authors presented VMs as a limiting factor. They argue that VMs provide an additional layer of indirection that make it more difficult to have a global picture of all the resources.

Limitations and Problems I had

I think it was strange that the authors tried to come up with a solution for both multicore and cloud computing. I prefer the approach of Barrelfish, where the researchers only focus on multicore and were thus able to come up with a more thorough solution in my opinion.
I also felt that the topic of security and isolation was left out in the paper. They talk about the disadvantages of VMs and state that their system provides a uniform view of all global system resources. However, one of the main benefits of having VMs is that they provide protection, and it would have been helpful if the authors discuss how protection was ensured when there was only a single system image OS. For example, in case of a compromise of fos, is there some mechanisms to do damage control, or is the attacker inevitably able to access all resources of the whole cloud?

Reading Notes: multikernel

Some of my reading notes for the paper "The Multikernel: a new OS architecture for scalable multicore systems".

Things I liked and that were interesting

I found it interesting that the authors decided to incoorperate ideas from distributed systems and networking into their OS. By regarding each CPU core as an independent unit and only using message passing, they said that they could exploit insights and algorithms from distributed systems.

I also found it interesting that they chose to make OS structure hardware neutral. At first this statement didn't make much sense to me, because one would think the OS is the most hardware dependant layer. Then they explained that by this they meant the design decision to separate OS structure as much as possible from the hardware specific parts (messaging transport system and device drivers). I think if one would really succed in making it as hardware neutral as possible, this would significantly facilitate the OS development process.