[oracle] How to find available directory objects on Oracle 11g system?

I assume this information is available in Oracle metadata tables, but where exactly ?

I need the directory object for BFILENAME as in this answer: Using PL/SQL how do you I get a file's contents in to a blob?

I tried:

select * from all_objects where object_type ='DIRECTORY';

OWNER                  OBJECT_NAME
------------------------------ ------------------------------
SUBOBJECT_NAME          OBJECT_ID DATA_OBJECT_ID OBJECT_TYPE
------------------------------ ---------- -------------- -------------------
CREATED         LAST_DDL_TIME   TIMESTAMP       STATUS  T G S
------------------- ------------------- ------------------- ------- - - -
 NAMESPACE EDITION_NAME
---------- ------------------------------
SYS                ORACLE_OCM_CONFIG_DIR
                    12689        DIRECTORY
2010-03-30 10:16:30 2011-01-10 12:49:39 2011-01-10:12:49:39 VALID   N N N
     9

SYS                DATA_PUMP_DIR
                    12764        DIRECTORY
2010-03-30 10:16:43 2011-01-10 12:49:38 2011-01-10:12:49:38 VALID   N N N
     9

SYS                XMLDIR
                    57134        DIRECTORY
2010-03-30 10:29:37 2010-03-30 10:29:37 2010-03-30:10:29:37 VALID   N N N
     9

But based on the output timestamps these are not the dirs created for me. This also doesn't show what is the real OS filepath for the object.