因为在C语言草创的年代，UNIX是最好的大型机系统。后来又用C语言重写了UNIX代码。

时至今日，UNIX和它的各种发展型仍然是最好的大型机系统。C语言也是最好的底层开发语言之一。

-Since all by himself at the age of C language, UNIX mainframe systems are the best. Later, using C language to rewrite the UNIX code. Today, UNIX and its various development still is the best type of mainframe system. C language is the best one of the underlying development language.