Re: nanobsd [was Re: Cross compiling user applications for armv7]

On 9/19/2025 22:30, Zach Metzinger wrote:
> On 9/19/25 20:58, Mark Millard wrote:
>> Not that I'm familiar with the details, but I'll note
>> nanobsd as a possible source of some ideas for builds
>> and installs for embedded applications, not necessarily
>> tied to the specifics above:
>>
>> https://man.freebsd.org/cgi/man.cgi?nanobsd
>>
>> Some quotes:
>>
>> "nanobsd.sh  --  utility used to create a FreeBSD system image 
>> suitable for embedded applications"
>
> This is fantastically useful to know. Thank you, Mark!
>
> I have a number of Beaglebone Greens in the wild that use read-only 
> root with /tmp and /var mounted as tmpfs. This is done auto-magically 
> by standard FreeBSD when / is marked ro in /etc/fstab.
>
> Quite useful when something is powered from an unreliable/limited 
> energy source, such as solar.
>
I use both nanobsd and Crochet (which is old but leverages the same 
paradigm) to build "embedded" images and those which MUST come back 
online unattended after a power failure -- like your Internet gateway, 
for example... :-)

The gateway, for example, boots from a USB stick and my home control 
stuff runs on the Pi series and boots from the microSD card.

There are ways to have that also be two-root-partition allowing 
"near-line" updates (update the other partition with the new OS code 
then reboot to activate it) provided you have a deterministic way to 
know which device the loader will boot from.  On EFI boot machines this 
can be problematic to obtain deterministically once the system is running.

-- 
Karl Denninger
[email protected]
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