I'm thinking about designing a system for a project using some single-board computer (RaspberryPi, CubieTruck etc) that runs Linux.
My main requirement is keeping the complexity of the booted SD card to a minimum - my vision is something like:
/
boot.txt
settings.txt # DHCP /ifconfig data etc.
error.log # optional
OS.tar.gz # the OS Omni-file
Kernel.img # If it can't fit with the Omni-file
The OS doesn't have to modify its files, except possibly for some error log.
My best guess so far is booting from an actual ISO using easy2boot, but the layout isn't trivial enough (and it seems kinda backwards).
Is there any project / boot option that can help me achieve my goal?
update
I found out about loop devices, which look like what I need - a FS inside a file.
I managed to format and mount it, like:
losetup /dev/loop0 /tmp/disk.img
mkfs -t ext2 /dev/loop0
losetup -d /dev/loop0
mkdir /tmp/disk-mount
mount /tmp/disk.img /tmp/disk-mount -o loop
touch /tmp/disk-mount/bla
umount /tmp/disk-mount
Is there any documentation for booting from such a device?