External SD Card & Internal Flasher Media in ICS

Two methods:

1. indicate external sd card based on internal flasher media(NAND or SD/MMC)

http://stackoverflow.com/questions/6156649/is-there-a-documented-way-in-android-2-x-to-inspect-multiple-sd-cards-for-cont?answertab=active#tab-top

2. update Android SDK, exist /sdcard, /external_sd and /udisk

Environment.getExternalSDStorageDirectory()Environment.getExternalUDiskStorageDirectory()Environment.getExternalExtSDStorageDirectory()Environment.getExternalSDStorageState()Environment.getExternalUDiskStorageState()Environment.getExternalExtSDStorageState()

To access media through MediaProvider, the Android application should use the URL content://media/external_sd, content://media/external_udisk, and content://media/external_extsd for the
specific media files in /sdcard, /udisk, and /exts, respectively.

http://reviews.androids.name/2011/03/i-mx-android-firmware-developers-manual-very-good/