Using the micro-SD card

David Corking lists at dcorking.com
Wed Aug 22 18:49:10 CEST 2007


On 8/22/07, Brian Schrock <schrock.brian at gmail.com> wrote:
> > However, I am still wondering if it isn't possible to use the Neo1973 as
> > a card-reader/writer from my desktop PC (running Slackware), as I would
> > really prefer not to have to every time I have a new image, move the SD
> > card from the Neo to the PC and back. Such an excersize *will*
> > eventually ruin the SD card holder in the Neo.
...
> > Then, does it also mean that I have to format the SD card to ext2 in an
> > external to the Neo, card reader/writer?
> > Or is it possible to use the default vfat file system on the card?
> >
> I have not formatted any of my cards yet, not sure what the card was
> that came with the neo (I never looked), but the my new 2GB card is
> vfat and maybe that is why I am having problems with mine...

The 512K SanDisk card that came with my Neo mounts automatically.
'mount' gives this :

/dev/mmcblk0p1 on /media/card type vfat
(rw,sync,fmask=0022,dmask=0022,codepage=cp437,iocharset=iso8859-1)

So you can see it is preformatted with a vfat-compatible filesystem

I have tried with a couple of kernels and rootfs - see
http://wiki.openmoko.org/wiki/User:Dcorking - the vfat and sd drivers
and the automount magic were included in the ones I tried.

To save taking the cover off the phone, I wrote to it with 'scp'.
Since the phone is USB 1.1 it will be quite slow.

Unfortunately, when I tried on Monday, scp exited without an error
(that I recall) at 368k of a 3M file.  Today the whole 3M file
transferred (and the md5 fingerprints match.)

I don't know if u-boot can boot a kernel from vfat, but if not, mke2fs
is included on the phone.

> > Just out of curiosity, what issues have you seen with a 2GB card? I
> > suppose that so far, only SD is supported, and not SDHC?
> >
> I am not sure what SDHC is (And too lazy right now to look it up) but
> my card was a standard cheapo kingston 2GB micro SD card from
> Microcenter (like $40). I stuck it in and tried to copy a 300+MB file
> and it failed part of the way through. I have not looked into why yet,
> but I will soon.

Kingston cards may not be compatible yet - see for example:
http://lists.openmoko.org/pipermail/openmoko-uboot/2007-February/000012.html

I seem to recall someone mentioned concern about sizes over 1 GB, but
I can't put my hands on any documented rumours.

David



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