[ECOS] Sharing JFFS2 file system between ecos and linux

Thomas Koeller thomas.koeller@baslerweb.com
Mon Mar 15 18:00:00 GMT 2004

Hi David,

I am currently researching ways to boot Linux on an embedded
system. The system's only persistent storage is some amount
of flash memory. So I came acrross the following idea:

I create a JFFS2 file system containing the kernel image as
a file. Some of the flash memory is set aside to contain an
instance or RedBoot, which has support for reading files
from JFFS2. RedBoot loads the kernel and executes it. The kernel
then mounts the JFFS2 as its root file system. A simple and elegant
solution, of course, but will it work? I guess not.

When analyzing ecos-created JFFS2 images using jffs2dump I am
getting lots of warnings, like so:

Wrong bitmask  at  0x00fe45dc, 0x1000
Wrong hdr_crc  at  0x00fe04bc, 0x98f7fb1d instead of 0x5936d419

The second warning is most likely caused by different checksumming
algorithms. I am not sure about the 'wrong bitmask' lines, though.
Would it be difficult to achieve full compatibility across both
platforms, so that file systems could be shared? That would be a useful
feature, and as a bonus jffs2dump could be used on ecos-generated
file systems.

I'd really like to hear your opinion!


Thomas Koeller, Software Development
Basler Vision Technologies

thomas dot koeller at baslerweb dot com


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