anchor.diff:    (let ((n (sys.int::ub16ref/le array 0)))
       (values (ldb (byte 5 0) n)
               (ldb (byte 4 5) n)
  -            (ldb (byte 7 9) n))))
  +            (+ 1980 (ldb (byte 7 9) n)))))
   
   (defun root-dir-sectors ()
     0)
  
positive.code:   (error "Feature not implemented: ~a" 'rename-file-using-host))
  
  (defmethod file-write-date-using-host ((host fat32-host) path)
    (error "Feature not implemented: ~a" 'file-write-date-using-host))
  
  (defmethod delete-file-using-host ((host fat32-host) path &key)
    (error "Feature not implemented: ~a" 'delete-file-using-host))
  
negative.code: ;;; bits 0-4 2-second count, 5-10 minutes, 11-15 hours
  (defun decode-time (array)
    (let ((n (sys.int::ub16ref/le array 0)))
      (values (ash (ldb (byte 5 0) n) 1)
              (ldb (byte 6 5) n)
              (ldb (byte 5 11) n))))
  
  