OSDev.org

While the virtual machine and just-in-time compiler in ring0 can cause performance penalties there are also some improvements over the usual microkernel design: IPC is done very quickly in a managed os as it is just a memcopy() operation if the communicating tasks reside in one address space. Furthermore there is no need for page directory switches - all tasks can be put into the same page directory (i.e. if it is large enough, e.g. on 64-bit cpus). The cost of syscalls is also reduced: They can be done using a usual call instruction. IIRC there were some benchmarks that showed that singularity's system calls were many times faster than windows' and linux'
system calls. So my answer is yes: managed os are viable as widely used desktop os.

@jnc100
I don't have any releases or a website yet, my os does not have any fancy features yet. I'm currently working on the user-space garbage collector. As soon as it works I'll write some drivers. Maybe I'll release some code after I have few utilities like a shell and a text editor working.

Thanks for clearing that up - I was under the impression that this type of managed kernel was still using memory space switches for running it's services. As you say though, this wouldn't me necessary with managed code as long as the address space was large enough (a fact that had escaped my attention).

Cheers,
Adam