POSITION

 Indicates the position of a file connected for sequential access.
 It takes the following form:

 POSITION = pos

 pos   Is a character expression with one of the 
       following values:

 'ASIS'   Indicates the file position is unchanged if the file 
          exists and is already connected.  The position is 
          unspecified if the file exists but is not connected.
          This is the default.

 'REWIND' Indicates the file is positioned at its initial point.

 'APPEND' Indicates the file is positioned at its terminal point 
          (or before its end-of-file record, if any).)

 A new file (whether specified as new explicitly or by default) is
 always positioned at its initial point.