5. The method of claim 4 wherein the deletion and addition of the original fixed sized code word node includes: establishing a priority queue to record nodes in the order they are used to represent subsequent strings of data; updating the history index of the original fixed sized code word node and moving the record of the node to the start of priority queue.
5. The method of claim 4 wherein the deletion and addition of the original fixed sized code word node includes: establishing a priority queue to record nodes in the order they are used to represent subsequent strings of data; updating the history index of the original fixed sized code word node and moving the record of the node to the start of priority queue. 6. The method of claim 5 wherein the deletion and addition of the fixed sized code word node includes: establishing a second priority queue to record empty nodes in the order that they are deleted; and moving the record of the deleted node to the end of the second priority queue.