PPD Directory Field Attribute

    +---------------+
    |R|R|R|R|R|R|R|D|
    +---------------+

    The last 7 bits are  reserved  and  only  bit 0 is used.  The other 7
    bits must be 0.

    Bit 0 is the Directory  or  sub-database  bit.   If  this is set then
    the data found at the  specified  address  is  actually  a PPDatabase
    itself.  This  can  be  accessed  with  CrossIntoDatabase.   This  is
    effectively a sub directory if  you  treat  each directory entry as a
    file.