: You may be right. Do you know any books or manuals or magazines or other WP:RELIABLE sources that discuss the compatibility (or lack of compatibility) between the Cray-2 and the Cray-3? 
 : So far, we have a reference in the article that says that, early in the design of the Cray-3, it was *intended* to be compatible with the Cray-2, but we don't yet have any sources that specifically say whether the actual shipped computers were binary compatible or source compatible or not.