I bought a camera a few days ago. Eagerly wanting to import the images from the SDHC flash card I use with the camera I noticed my laptop came equiped with a flash card reader. It felt a little bit nostalgic as I inserted the flash card in the slot, reminding me to the days of floppies but better, instead of the always magneticly recorded data on the mechanical floppies. Which always seemed to loose data no matter how gentle you treated the disk. I have never had a flash card break.
I have no software to automatically mount newly detected storage media. So it was up to me to somehow figure out what file in /dev the device would be represented by. As I asked for advice on how to do this on the Archlinux IRC channel I got two very nice tips:
First by reading the messages from the message buffer of the kernel right after I inserted the card in the flash reader, using:
$ dmesg | tail
which yielded on the last lines of the buffer the messages,
mmc0: new high speed SDHC card at address bddc mmcblk0: mmc0:bddc SD04G 3.69 GiB mmcblk0: p1
I could get the necessary information of what the kernel was doing. As one can see all was fine, I was a little bit worried because the text printed above the flash reader only says, “SD/MMC – MS/Pro”, so I was not sure it would support the SDHC standard. While the messages from dmesg is very human readable it only hints at what file you should mount in order to access the flash card. A quick search on the interent shows that for some people the file was named mmc0 but that file did not exists on my system so to find out the full name of the file, I used:
$ ls /dev -l | grep brw
brw-rw---- 1 root disk 7, 0 Jul 9 02:55 loop0 brw-rw---- 1 root disk 179, 0 Jul 9 04:53 mmcblk0 brw-rw---- 1 root disk 179, 1 Jul 9 04:53 mmcblk0p1 brw-rw---- 1 root disk 8, 0 Jul 9 02:55 sda brw-rw---- 1 root disk 8, 1 Jul 9 02:55 sda1 brw-rw---- 1 root disk 8, 2 Jul 9 02:55 sda2 brw-rw---- 1 root disk 8, 3 Jul 9 02:55 sda3 brw-rw---- 1 root disk 8, 4 Jul 9 02:55 sda4 brw-rw---- 1 root optical 11, 0 Jul 9 02:55 sr0
Then simply mounting the file mmcblk0p1 at the location of my choice gave me access to the flash card.