这个只跟硬盘有关，跟操作系统是什么没有关系。主引导记录告诉机器从哪里启动系统，所以一般来说主分区是安装系统的。

This limitation is due to something called the Master Boot Record which tells the computer which partitions it can boot from, and so primary partitions are usually reserved for operating systems.

youdao

现在键入root (hd0, 0)(或者是你自己得到的返回值)，以告诉Grub该从哪个分区启动，然后键入setup (hd0)以在你的硬盘主引导记录重新安装引导程序。

You should now type root (hd0, 0) (or your equivalent) to tell Grub which partition is being used to boot from, followed by setup (hd0) to reinstall the boot loader into the disk's master boot record.

youdao

硬盘则不同。硬盘有一个MBR(主引导记录)，这是因为一个硬盘可以有多个分区，并且其中的任何一个分区都可以是可启动的。

A hard disk is different. A hard disk has an MBR (Master boot Record), this is because a hard disk can have multiple partitions and any one of them can be bootable.

youdao

不过对于JOS，我们将使用传统的硬盘驱动器启动机制，这意味着我们的启动引导程序必须符合那微不足道的512字节。

For JOS, however, we will use the conventional hard drive boot mechanism, which means that our boot loader must fit into a measly 512 bytes.

youdao

不过对于JOS，我们将使用传统的硬盘驱动器启动机制，这意味着我们的启动引导程序必须符合那微不足道的512字节。

For JOS, however, we will use the conventional hard drive boot mechanism, which means that our boot loader must fit into a measly 512 bytes.

youdao