[yocto] Trying to understand my boot configuration

[Paul D. DeRocco]

I have a simple x86_64 system based on Morty, and I'm trying to understand
the way the system boots. The disk image file is a FAT16 parition which I
use as the second partition on my SSD, with the boot flag set. (The first
partition is a FAT16 partition that contains a bunch of data files and my
application.) The boot partition contains a file called rootfs.img, which
obviously is my rootfs.

GRUB is the boot manager on this 64-bit system, and it puts up a menu of
four items that allows me to specify graphics or serial as the console,
and either booting or installing. After booting, I see that rootfs.img is
loop mounted as the root.

My questions are:

1) Is this a "live image" boot? As I understand it, a live image is a
system that boots from removable media, and gives the user a choice
between copying its rootfs to a RAM disk and running a volatile session
from there, or installing the rootfs somewhere. Since I see "install" menu
items in GRUB, that suggests that this is a live image. But at runtime the
rootfs appears to be on the actual drive, not in RAM, because my command
history persists across reboots.

2) Why do I have a FAT partition with a loop mounted root file system, in
the first place? Is it possible to boot directly into a plain ext3
partition? I tried using the ext3 partition image as-is, but it hung on
boot if I used an MBR, and complained there wasn't a bootable partition if
I used a GPT.

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Ciao,               Paul D. DeRocco
Paul                mailto:pderocco at ix.netcom.com