SD card not detected as mmcblk0

I have a Sandisk 8GB microSD card but as I insert it in the computer it is detected as sdbbut not as mmcblk0


It’s not matter, some computer convert the SD interface to USB, if then, the SD card will be detected as sd*.

Thanks Steven,
I sorted out the problem. Now the 12.04 runs on the beagleboard. But there is another problem the interface is too slow and it cannot run audio and video files. When I checked on the angstrom audio as well as video is playing well.