JFFS2, CF, PCMCIA adapter, ATA

[David Woodhouse]

On 4 Nov 2001, Michael Rothwell wrote:

> I've been trying to create a jffs2 image on a 16MB compact flash card
> today. I've got a pcmcia-to-cf adapter that works well for treating the
> CF like a small disk.

The CF _is_ a small disk. You may think it has flash inside - we couldn't 
possibly comment. As far as you're concerned, it's just alien technology 
which allows them to stick a real IDE hard drive inside that package and 
stops you from hearing the whirring sounds.

There is a driver which uses a real hard drive as backing store for a 
faked MTD device - see the 'blkmtd' driver. I haven't used it - others can 
perhaps give you more helpful advice.

> How do I create a "loopback" jffs2 filesystem? 

# insmod mtdram total_size=16386 erase_size=64
# dd if=jffs2-image of=/dev/mtdblock0
# mount -t jffs2 /dev/mtdblock0 /mnt/jffs2

> How do I create a jffs2 filesystem on the CF card using the PCMCIA adapter 

# dd if=jffs2-image of=/dev/hda (or hda1, hda2, etc.) 
# insmod blkmtd device=/dev/hda
# mount -t jffs2 /dev/mtdblock0 /mnt/jffs2

You may want partitioning if you want to boot from this too, not just use 
it as filesystem.

> I'm using 2.4.13, with mtd and jffs2 compiled in. No devfs.

There have been some blkmtd updates since then. I'm hoping the maintainer 
will send those to Linus if appropriate.

-- 
dwmw2