[johnnym]

I think NetBSD perhaps fit SGI machines better? It's more lightweight and they won't remove hardware support easily.

Well, the list of supported machines for NetBSD/sgimips doesn't actually speak for that and not everything works as stated (for example Indigo R3000 doesn't work with the shipped kernel last time I tested but only with out-of-tree modifications by a Japanese developer) - and now compare that to what OpenBSD/sgi has to offer - but as OpenBSD retired/abandoned the sgi platform there is some point in that. Though they didn't do it easily, it took them multiple versions (6.6 to 6.9) to finally do it.

And that is also a main advantage I think, because you can basically do what you like with it now, because there's no gatekeeper between your changes and the source code. I for example try to maintain OpenBSD/sgi and follow the main code base and fixing stuff as best as I can, but you could maybe do real development there. For starters I believe there's still stuff not yet ported from NetBSD/sgimips to OpenBSD/sgi, e.g. the sound hardware in Indigo, Indy and Indigo².