[eschaton]

It should just be a matter of producing a kernel and, if necessary, RAM disk that can be booted the same way as Linux.

[jonhohle]

“just” is doing a lot of work in that sentence.

[eschaton]

Yes and no; kernels aren’t magic, and “change how this kernel is loaded to match how Linux does it” is actually a reasonable first assignment for an Operating Systems class at a top-tier school. (You’re basically just creating an alternative `main()` if you don’t need a RAM disk image from which to load drivers.)

[cpach]

Then one needs to launch it. Not sure if there are any lancher UIs out there, or if one has to write custom code for that.

[fragmede]

Parallels will run a VM that can (manually) boot bsd.rd from the EFI shell if you stick BOOTAA64.EFI and bsd.rd on a FAT32 GUID formatted.dmg, connect it to the VM, then boot EFI shell. Type:

    connect -r
    map -r
    fs0:
    bootaa64.efi
    boot bin.rd

Then you'll be in the OpenBSD installer, having booted an OpenBSD kernel.

You can grab the files from: https://ftp.openbsd.org/pub/OpenBSD/snapshots/arm64/

Actually installing the system is left as an exercise for the reader.

[eschaton]

My point is that as long as OpenBSD can boot like Linux, you just have to tell whatever VM front-end you’re using that you’re booting a Linux but give it an OpenBSD kernel and RAM disk.

Traditionally BSD has booted very differently than Linux, because Linus adopted the same boot process as MINIX when he first developed it (since he was actually using the MINIX boot blocks at first).

BSD has historically used a bootstrap that understands V7FS/FFS and can load a kernel from a path on it. MINIX takes the actual kernel and RAM disk images as parameters so it doesn’t need to know about filesystems, and that tradition continued with Linux bootstraps once it was standalone.