1、采用无缓冲方式实现文件读写。2、采用高速缓存实现文件读写。3、采用异步方式实现文件读写。以及三种方式的比较。-1, unbuffered file read and write. 2, file read and write cache. 3, the use of asynchronous file read and write. And comparison of the three ways.