anchor.diff:                                :if-exists if-exists
                                 :block-size (bytes-per-cluster ffs)
                                 :dirty-bit dirty-bit
  +                              :block-n block-n
  +                              :buffer buffer
                                 :buffer-position buffer-position
                                 :position file-position
                                 :length file-length
  
positive.code:                               :if-exists if-exists
                                :block-size (bytes-per-cluster ffs)
                                :dirty-bit dirty-bit
                                :buffer-position buffer-position
                                :position file-position
                                :length file-length
  
negative.code:                  (:create
                    (multiple-value-setq (buffer-position dir-array file-offset)
                      (create-file host dir-array dir-cluster (pathname-name pathname) (pathname-type pathname) nil (ash 1 +attribute-archive+)))
                    (setf buffer (make-array `(,(bytes-per-cluster ffs)) :element-type '(unsigned-byte 8))
                          block-n 0
                          dirty-bit t
                          abort-action :delete))
                   ((nil)
                    (return-from open-using-host nil))))
  