I got this section:
Direct-load INSERT with no-logging. In this mode, data is inserted without redo or undo logging. (Some minimal logging is still done for marking new extents invalid, and dictionary changes are always fully logged.) When applied during media recovery, the extent invalidation records mark a range of blocks as logically corrupt, since the redo data is not logged.

out of this Link:
http://otn.oracle.com/doc/oracle8i_8...dlins.htm#2545

Here is another link:
http://otn.oracle.com/doc/oracle8i_8...5/c09parti.htm

Hope this helps.