Indicates run-time library behavior following WRITE operations.  It
  takes the following form:

  BUFFERED = bf

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

       'NO'   Requests that the run-time library send output
              data to the file system after each WRITE
              operation.

       'YES'  Requests that the run-time library accumulate
              output data in its internal buffer, possibly
              across several WRITE operations, before the data
              is sent to the file system.

              Buffering may improve run-time performance
              for output-intensive applications.

  The default is 'NO'.

  On OpenVMS, BUFFERED has no effect.  The operating system
  automatically performs buffering, which can be affected by the
  values of the BUFFERCOUNT and BUFFERSIZE keywords when the file is
  opened.