booting disk image on a USB thumb drive

[David H. Lynch Jr.]

     I am looking to create a USB thumb driver with grub2 and boot 
linux from a disk image on the thumb drive.
    This is similar - but not identical to booting an ISO image - the 
disk image would be formated to ext2 or reiserfs or something like that 
rather than iso9660.
    I am looking to do something that is essentially the same as what 
ubuntu wubi does under windows - except on a flash device.


    I can handle building a custom kernel image as required, as well as 
a custom initrd/initramfs.

    Is there any approximation of a howto on this ?

    I am also not sure I conceptually understand how grub is dealing 
with this.
    If the linux kernel and initrd are outside the disk image should I 
need the grub loop facility at all ?
    I would think only the init scripts on the booting copy of linux 
would need to know they were using a disk image.






--
Dave Lynch                                                  DLA Systems
Software Development:                                    Embedded Linux
717.587.7774           address@hidden     http://www.dlasys.net
Over 25 years' experience in platforms, languages, and technologies too 
numerous to list.

"Any intelligent fool can make things bigger and more complex... It takes a touch of 
genius - and a lot of courage to move in the opposite direction."
Albert Einstein