anchor.diff:  (defmethod read-header ((file file))
     (let ((buffer (make-array 8 :element-type '(unsigned-byte 8))))
       (with-slots (stream header) file
  -      (file-position stream +header-position+)
  -      (assert (= (length buffer) (read-sequence buffer stream)))
  +      (read-block buffer stream +header-position+)
         (setf header (make-header :free-list    (peek32 buffer 0)
                                   :record-table (peek32 buffer 4))))))
   
   (defmethod write-header ((file file))
     (let ((buffer (make-array 8 :element-type '(unsigned-byte 8))))
       (with-slots (stream header) file
  -     (file-position stream +header-position+)
  -     (setf (peek32 buffer 0) (header-free-list    header)
  -           (peek32 buffer 4) (header-record-table header))
  -     (write-sequence buffer stream)
  -     header)))
  +      (setf (peek32 buffer 0) (header-free-list    header)
  +            (peek32 buffer 4) (header-record-table header))
  +      (file-position stream +header-position+)
  +      (write-sequence buffer stream)
  +      header)))
   
   
   (defun valid-type-p (type-code)
  
positive.code:                                                                     (2.1 2.2)
                                                                      (3.1 3.2)
                                                                      (4.1 4.2))))
               (write-record file 40 "Hello world!"))
          (lse-data-file-close file))))
    (test/dump-lse-file  "/tmp/test.don"))
  
  
negative.code:   (with-slots (stream header record-table) file
      (unless header
        (read-header file))
      (when (zerop (header-record-table header))
        (build-record-table file))
      (let ((buffer (make-block)))
        (file-position stream (header-record-table header))
  