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Comment by Animats | Hacker News Reader

I'd really like to see an open-source QNX-type microkernel in Rust. Everybody is re-implementing early Unix in Rust, but that's not a good model. The great thing about the QNX model is that the tiny kernel barely changes from year to year, because everything is outside it and not very trusted. So it approaches being totally debugged.

L4 is too low-level - you have to run another OS on top of it, usually Linux. QNX offers a POSIX interface.

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> QNX offers a POSIX interface.

You say that like its valuable. POSIX has a lot of problems, if you're going to go through the trouble of throwing away a mature kernel like Linux with all the hardware support that brings, you may as well also ditch your POSIX baggage.

What is the state of documentation on QNX? Is there sufficient documentation that it would be possible to write a QNX-compatible kernel from the documentation (plus access to a QNX machine, which has to be available somehow outside of industry, right?)?

Until Blackberry bought it, it was open source. There were free downloads. Now it's proprietary. But there's a lot of info out there from the open source era. The manuals are available.

Here's the original QNX paper.[1]

[1] https://cseweb.ucsd.edu/~voelker/cse221/papers/qnx-paper92.p...

I am amazed that I cannot find a copy of the source code from the time it was freely available now.

Here's the 2007 press release announcing QNX going open source.[1]

On April 9, 2010, the day the acquisition closed, Research and Motion took the source code offline, with no notice. All user open source projects on QNX were abandoned shortly thereafter.[2]

[1] http://www.qnx.com/news/pr_2471_1.html

[2] https://community.qnx.com/sf/sfmain/do/listProjects

Would it be possible to use rump kernels with this to get support for the myriad hardware out there from the get-go? Or are QNX-esque microkernels and rump kernels mutually exclusive for some reason?

Using the drivers from rump kernels with a QNX kernel might work. QNX runs drivers, file systems, and networking in userland. The rump kernel people have those components. The QNX kernel itself does only memory allocation, process management, CPU dispatching, timers, and inter-process messaging. So it's tiny, relatively trouble-free, and has a small attack surface.

So if someone implemented a QNX-style microkernel in Rust, file systems and networking could be adapted from rump kernels. Drivers would require more porting. That would be a nice way to get a usable but small OS for embedded and IoT devices. Linux has more than you want in an embedded device.

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