anchor.diff: +;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
   ;; Specification:
   ;;
   ;;     (ubyte position)  - byte = 8bits  (== byte)
  
positive.code: (def-nxt-command start-program #x00 #x00 file-name (string 2 21))
  (def-reply-package #x00)
  
  (def-nxt-command stop-program  #00 #01)
  (def-reply-package #x01)
  
  (def-nxt-command play-sound-file #x00 #x02 loop (ubyte 2) file-name (string 3 22))
  
negative.code: (defun last-byte-of-spec (spec)
    "Returns the last byte in the command vector occupied by spec."
    (case (type-of-spec spec)
      (uword (+ 1 (second spec)))
      (ulong (+ 3 (second spec)))
      (t (car (last spec)))))
      
  (defun command-length (command-spec)
  