(edit added later so that we get credit going where it's due: It occurred to me that it was Sebastian Wicki who was campaigning for the no-userspace mode last summer as part of his lowRISC project, and did the initial work to be able to again use Rumprun without "userspace". Apparently my memory of events goes only a few weeks back if I don't think about things carefully ...)
Now, if I'm allowed to summarize rump kernels, I'd say the goal is to build a framework which incorporates enough of the past to allow things to work, but tries to be as flexible as possible so as to enable the future. I'm a firm believer in "there's no such thing as #1", which means you shouldn't produce software components which work only in one type of tool, because it's easy to foresee that right around the corner you'll have to build components for the next tool.
p.s. "Atti"? That one was new, usually it's "Antii" or something like that ;) ;)
Having everything in-kernel (single memory space) with POSIX-y API for applications the right direction ?
or I just brain farted here ?
Anyway, that's the right direction if that's what you want you want to accomplish. Otherwise it's the wrong direction.
sincerely, anti
POSIX is just the part of UNIX that should have been part of the C runtime, but instead they made it into an optional standard.
Almost ever other programming language with richer runtimes don't have any need to depend on POSIX.
All their APIs for creating processes, threads, accessing file systems, communicating over the network aren't POSIX dependent.