Device is capable for automatic detection and use of supported external drives (FLASH drives, USB drives).
There will be an attempt to mount all available partitions in case when supported external drive connected.
Contents of every valid partition will be available for file operations in so-called "mount points". Those mount points located in /media/ folder and have format USB-<XXX>-<YYY> where XXX is the serial number of connected drive and YYY is the partition number (count from 1).
There is an additional information available for mount points using /home/default/rdir.cgi get_storage_info sub function. Without arguments get_storage_info returns an array of JSON objects, which holds an information about every mount point available at the moment. Or you can supply get_storage_info sub function with the argument of interested mount point (excluding /media/ prefix).
The same can be done in browser with gSTB.GetStorageInfo function.