方法一：cmd
fsutil file createnew c:\100MBfile.txt 104857600
方法二：
You can use the Sysinternals Contig tool. It has a -n switch which creates a new file of a given size. It will create a file almost instantaneous.
快速创建空白大文件用法：Contig.exe -n D:\wamp\1.tmp 2147483648