A file system MAY<8> support
alternate data streams within a file or a directory. For a general description
streams, section 1.1.
Every file has a default stream, which is the stream that is
referenced when no stream name component is specified as part of the pathname.
A directory does not have a default data stream; however, it can have named
alternate data streams.
For more information on stream naming, see section 2.1.5;
for more information on streams in general, see section 5.