When I used OpenBSD, I was a big fan of
bsd.rd: a kernel that includes a root file system with an installer and a few tools. When I invariably did something bad to my root file system, I could use that to repair things.
bsd.rdis also helpful for OS updates. And there is only a single file involved.
On NetBSD however, there is usually no
netbsd.rdkernel installed, or even available by default. The facility is there, it’s just not standard. To be fair, there are a number of architectures that use kernels with a ramdisk for installation.
Recently, I have been toying with NetBSD on an Orange Pi 5. This is a 64-bit ARM board, using the evbarm-aarch64 architecture. I am booting from an SD card (details in a followup post) but once booted, the kernel does not see the card any more, only the NVMe SSD. So my thoughts went back to
bsd.rdand I decided that I want one!
Such a kernel seems like a very useful tool to have, so if you’re running NetBSD – this guide will help you add it to your toolbox.