Once these changes ( dual mode , privileged instructions , memory protection , timer interrupt ) have been made to the basic computer architecture , it is possible to write a correct operating system 一旦對一個基本的計算機體系結(jié)構(gòu)完成了以上修改(雙模式、特許指令、內(nèi)存保護、定時器中斷) ,就有可能寫出正確的操作系統(tǒng)。