Re: L4Re with GCC 9; Repositories and Roadmaps

On Thursday 23. January 2020 12.44.29 Martin Decky wrote:
> 
> Sorry for playing Captain Obvious here, but there are other
> microkernel-based operating systems (both inside and outside the happy L4
> family :)) that might be closer to achieving this goal of suitability for
> general-purpose computing.
> 
> A curated list can be found at http://www.microkernel.info/

Well, I am aware of several of them, of course. Maybe my memory is failing me, 
but I am pretty sure I mentioned the Hurd in a recent message, and previous 
messages will have mentioned Minix 3 as well. Those two are probably the ones 
that most Free Software developers would recognise and investigate further. I 
have previously looked at Genode, HelenOS and various parts of seL4, mostly to 
see what kind of architecture they employ for certain aspects of the system.

My motivation for using L4Re to begin with was that it works on the MIPS 
architecture. Indeed, using it on the MIPS Creator CI20 was the entry point 
for using it on other related devices and for more general investigations. I 
did look into a number of different operating systems - microkernel and 
otherwise - as part of my familiarisation with the MIPS architecture, 
experimentation with bare-metal code, and gaining confidence in deploying low-
level software. (Of course, I was already using these devices with Linux, in 
case anyone feels the need to make me aware of its existence as well.)

The primary considerations for me when adopting software include things like 
whether...

 * I have a chance of running it on hardware I actually have
 * It can be used for practical things
 * It is documented beyond academic papers
 * Obtaining and deploying the software is relatively convenient

Where your interests and mine may diverge is that I am not particularly 
interested in whatever the current trends are with regard to microkernel 
design, even though some of these design elements may be useful and worth 
pursuing. Most of the "next big thing" microkernels that get announced tend to 
get abandoned in short order (often for the next "next big thing"), so I would 
rather focus on projects that have actually been around for a while.

Naturally, this might mean having to deal with an imperfect collection of 
mature software, hence my complaints about certain aspects of L4Re, although 
perhaps my most significant reservation about working with L4Re is that there 
doesn't seem to be any kind of community around it. Maybe if other independent 
developers were using it, there would be an exchange of ideas that would be 
beneficial to everyone concerned.

If you have any concrete suggestions of systems other than L4Re that provide a 
decent, if basic, level of support for running user space programs written in 
mature languages, that work on the MIPS architecture, and that have not 
already laid down a rigidly prescriptive system architecture that would make 
experimentation awkward, I would obviously like to hear them.

Paul