说明：  详细介绍了FAT文件系统（包括FAT12,FAT16,FAT32），不知是哪位牛人写的电子书，非常经典，多亏了它，我才完成了FAT文件系统在ARM上的实现
(Detailed the FAT file system (including FAT12, FAT16, FAT32), I do not know which cattle were written e-books, very classic, thanks to it, I finally completed the FAT file system on the ARM realize)