- programatically declare the /dev/ files and their permissions
- link the binaries you want to use
I've learned about crunched binaries (like busybox, but in reverse), so I wonder if there's a BSD way to do that.
There have been others in the past, but this seems to be the most polished and ready to use ATM(for FBSD).
Another would be NanoBSD (also FBSD).
For NetBSD you're on your own, starting from there https://wiki.netbsd.org/tutorials/how_to_create_bootable_net... , and/or asking on https://daemonforums.org/ , https://www.unitedbsd.com/ (taking inspiration from some 'live-distro' discussed there. like 'OS-108'), reddit(?), 'crap-overflow', and even https://www.linuxquestions.org/.
Of course you're free to use the official NetBSD mailing lists, and some obscure IRC-channels in even more obscure IRC-networks also :-)
(You won't be spoon-fed, and are expected to have read the manuals and other documentations...)
However, I need pointers to get started.
> You won't be spoon-fed, and are expected to have read the manuals and other documentations...
I read a lot of FreeBSD and NetBSD documentation to get to the point of compiling my own kernels, but I don't think I ever read about the equivalent concept of Linux cpio/initramfs for BSD. My minimal images use a UFS filesystem.
Here, after checking https://mfsbsd.vx.sk/ and https://github.com/mmatuska/mfsbsd/blob/master/scripts/mdini... I think mfsbsd is just a using tmpfs so it may not exactly the same thing as initramfs, that allows booting linux from a bzImage + initrd
I'll keep searching, it's not super high priority at the moment, but it's something I'd like to do with (Free|Net)BSD.
Back to topic, does it matter if it's using different mechanisms, if achieving the same result at the end of the day? Like running in RAM, and not necessarily having to be 'installed' on some medium, being very minimal, and optionally 'rebooting/remounting/pivoting' into something larger, which may also reside in RAM?
That OS-108 may have been misleading, because it seams rather dead, but I thought it did something like that, eons ago, when I looked at it in emulation.
https://github.com/OS108/OS108/tree/master/LiveImgScripts
Anyways, it's based on this https://github.com/tsutsui/netbsd-teokureliveimage , which isn't, most relevant would be mkimagebuilder.sh and mkliveimage.sh from there, I guess. If that doesn't get you further than your own minimal images, I've understood you wrong, and probably wasted your time.