Re: [Gumstix-users] MMC card and mount point

[Dave H. <dhy...@gm...>]

Hi Chuck,

On Fri, Aug 29, 2008 at 4:10 PM, Chuck Randall
<shi...@ro...> wrote:
> Yes, I expect my mmc card to be automounted at /media/card, but I
> don't see my card's contents in /media/card. The mount point appears
> empty.
>
> And, even if I don't have a mmc card attached, I still get a
> persistent, writable /media/card directory!

So filesystems are mounted onto a directory. If there is no filesystem
mounted, then it's just a directory on your local filesystem, and yeah
you can write files into it.

You can use the mount command to see what filesystems are currently
mounted onto which directories.

> So, I'm totally confused by this. Is /media/card really my mmc card or
> not??

Only if it's mounted.

> When I don't have a card attached, where is that space allocated
> from in /media/card, from flash RAM?

It will come from whatever filesystem /media/card would come from. So
if /media were mounted to a ramdisk, then /media/card would be from a
ramdisk (provided there is no mount on /media/card).

Often times, it will just be a directory on the jffs2 filesystem
that's mounted at /

> Stuff written there is persistent
> across boots. It sure doesn't go onto my mmc card.

Then it's going to the jffs2 filesystem.

-- 
Dave Hylands
Vancouver, BC, Canada
http://www.DaveHylands.com/