这条grub命令错在哪了？

elais

map (hd0,0)/hd.img (fd0)

C盘下面有hd.img文件，但grub显示error command

herberteuler

map
---

- Command: map to_drive from_drive
     Map the drive FROM_DRIVE to the drive TO_DRIVE. This is necessary when you chain-load some operating systems, such as DOS, if such an OS resides at a non-first drive. Here is an example:

          grub> map (hd0) (hd1)
          grub> map (hd1) (hd0)

     The example exchanges the order between the first hard disk and the second hard disk. See also Note DOS/Windows.