> 
> I use no slower than Class 10 mSDHC cards in mine. Anything slower takes for-ev-er to image. 
>

Right-on. I use my laptop for its card-reader/writer. Any ideas on one that I
should attach to desktops?


> There’s no way to add a SATA drive to the Pi without doing it over USB so there’s no benefit to that other than capacity to doing it that way - you’re probably better set using it as secondary storage and not running the OS from it. That’s the plan with my projects.
> 

Great advise. And this is also my conclusion. I want to OS to boot and rebuild
the RDWR partitions/mount-points so that I never corrupt the system itself,
which should run from RDONLY mount-points.

But where the data lives will be the USB-drive. That is why I need a robust
shutdown of the FS.


> I’ve run all my stuff off a massive 12VDC LGM battery for days at a time without issue and, to be fair, shutting down improperly is something the Pi just doesn’t have to worry that much about. Yes files get left open sometimes but I’ve never had one fail because of a file issue… entire cards have failed but never a boot failure caused by locked files.
> 

I had not looked closely on the booting sequence of the RPi to really know.
But I think you are right, that it has most of the OS in RDONLY mounts. But
data can be corrupt if collecting data is what one is doing.

Good pointer on the battery too. What I would like is to have a circuit to
monitor battery remaining capacity and attach it to the RPi itself. Info on
something like that?


> Tweaking can be done directly on the memory card, if you feel you have to, but I use SSH connections for my non-Zeroes to do my configurations if I don’t have a KVM handy.
>
 
I have done both. Remounting the partitions RW from a running system works
fine. What would be best is if I had a virtualization/emulation of the RPi
so that I can do all my booting testing on a VM. Ideas on that?

Thanks so much. This is great info!