Function FindDir(Var Data:DBaseDir):Word;

    Searches for a directory  item  with  name  and  number matching that
    specified  in  Data.   If   this   is  not  found,  it  searches  for
    a name match and if  this  is  not  found  it  searches  for a number
    match.  The directory details are then returned in Data.

    Notice that this  returns  where  in  the linked list the item can be
    found, not an error number.  0 is returned if none could be found.