古时候的文件传输靠的是驿站,一般每隔20里有一个驿站,一旦需要传递的公文上注明“马上飞递”字样,按规定要求每天300里,如遇紧急情况,可每天400里、600里,最快达800里。传递紧急文件时,每个驿站都用快马,这样,虽然不是千里马,但每匹马都死命跑。“六百里加急,八百里加急”用来表示情况紧急程度。在文学作品中,对此有精彩描写:“八百里加急!八百里加 File transmission in ancient times rely on the post, usually every 20 years there is a post, once the need to pass the official documents indicate ”fly immediately“ words, according to the requirements of 300 miles per day, in case of emergency, every day 400, 600, the fastest up to 800. When delivering emergency documents, each station uses a quick horse, so that although not Maxima, but each horse is running to death. ”Six hundred miles urgency, eight hundred urgent“ to indicate the urgency of the situation. In literary works, there is a wonderful depiction of this: ”Eight hundred li an urgent! Eight hundred Rica