[maemo-developers] Finding the mmc cards

From: David Hazel david.hazel at enchaine.com
Date: Wed Aug 29 23:11:38 EEST 2007
> You can also use the environment variables MMC_MOUNTPOINT and
> INTERNAL_MMC_MOUNTPOINT, but then you have to make sure that they are
> always set correctly in your environment.  (I don't think using
> environment variables for this kind of system information is a good
> idea.)

Those environment variables seem oddly inconsistent to an ex-VMS man like
it's necessary to remember which one the unqualified MMC_MOUNTPOINT refers
to (e.g. by remembering that the other one starts with INTERNAL rather than
EXTERNAL - which itself is counter-intuitive, as I would expect the internal
one to be the more "important" and therefore the unqualified one).

I also picked up on Tony's reply regarding the way in which /dev/mmcblk0 and
/dev/mmcblk1 seem to be reversed in semantics with respect to the cards they
relate to. With these two examples of inconsistency in card mappings, it
seems all the more important to me that some kind of API is provided that
can enumerate the cards with certainty (and with logical/naming consistency,
please!) and can determine a range of useful information about the cards.

Here are some ideas for the kind of information such an API might want to be
able to retrieve:
- serial number
- capacity
- whether FAT16 or FAT32 formatted
- mountpoint
- device file name
- whether write protected (yes, you can write-protect an SD card)

David Hazel

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