translation.en: It was such a radical change, in fact, that the early Macintosh development team in '82, '83, '84 had to write an entirely new operating system from the ground up.
translation.zh: 那是一个很彻底的改变，事实上， 早期的苹果机开发团队 在'82，'83，'84年 不得不完全从零开始写一个全新的操作系统。