It had to be robust, which is to say crash-proof, doing without many standard programming tools that give developers flexibility but can lead to unpredictable results.

• 它还必须是坚固可靠的，也就是说要具有防撞击性。它用不着很多标准的编程工具，这些工具为程序开发员提供一定的灵活性，但却会导致意想不到的后果。