Writing an OS in Rust

But has anyone actually done that? Can you even express those as safe interfaces in Rust?

I doubt they would give up that money stream in their current condition (automobiles for one market).

I asked, both before QS sold it to RIM and after the deal, in both cases I didn't even get an answer (and I would have been in a position to put up a substantial chunk of money in order to get a dual license deal in place). Real pity, but maybe it will still happen.

QnX is one of the most elegant OSs out there and having a public domain or GPL'd version of it would be a great thing.

I'm hoping they open source QNX after the Blackberry disappears. The Blackberry is a dead end, but we really need something solid for embedded work.

seL4 is quite good, but their approach to message passing has a problem. Messages are limited to a few bytes passed in registers. Anything bigger has to be done through shared memory between processes. This is great for the kernel; it never has to do a long operation like a big copy, so there's an upper bound on the time for each kernel operation. But with shared memory, one process may be able to mess up another. The usual library for L4 shared memory puts multiple "chunks" into one shared memory area, with an allocator. "A shared memory area can have multiple chunks."[1] Messing with the chunk structure or the wrong chunk from one process may adversely affect another one. That's a bad kind of attack surface.

So, although the kernel is secure, server processes with higher privileges than their callers may not be. Since this is how processes talk to file systems and drivers, it's an obvious way to attack.

QNX copies data from one process space to another. This adds copying overhead, but it's usually not too bad, because 1) most messages are short, and 2) if you just created a message and sent it, it's in the cache. In practice, the big overhead item today is context switching.

[1] http://l4re.org/doc/group__api__l4shm.html

This seems to be about using Rust for the kernel running inside the virtual machines, not for the hypervisor itself, which is what I was talking about.

> Well, Rust is a systems language, and so it should be a good fit for OS development. We're still working on bits of it, but it's a stated goal of the language, so testing that out is valuable.

My questions was not well formulated. Let me rephrase it: C is also a system language and there are plenty of OS libraries written in C. C++ could be seen as another system language. Even the syntax of Rust is similar to C/C++ according to Wikipedia article. So, what's the advantage of Rust over other systems language? Better support for autonomous systems? Reflective model? Do you have a paper? It is a research project? Do you plan to replace Linux or something like that?