I have a Linux operating system, grub is installed at the boot partition.
There is two fat32 partitions in the harddisk, hda1 and hda5,
I want to add a DOS operating system to the computer, and add a entry for it in the Multiple Starting up Menu of grub, can I achieve this?
Thank you.

The dos system will have to go on hda1. If that one is free, there should be no problem. Add the right entries to grub (sorry, I'm not familiar with grub but should be no different from adding an entry for windows, so just search in the forum), and things should be fine.

I don't want to install windows operating system,
I want to install DOS operating system, such as freedos9, freedos32.
It isn't difficult to install freedos in a floppy disk,
it is difficult to install it in the harddisk to me.
How to install freedos OS in harddisk?

You need to set the hda1 active if not already so with fdisk. I assume the partition is formated. Boot with your floppy disk and install. Its been forever since I played with freedos so not sure how to install to the hard drive.

Add this to your grub conf file.

title DOS
rootnoverify (hd0,0)
chainloader +1

what do you want to run a 'dos' for would it be possible to use bochs or dosemu for what your trying to do?

Thank you, quatsch, michaelk, and kev82.

Perhaps grub for dos is a good choice, however, I want to have a try to boot dos without it. Just is a try.

Hi, kev82, I want to install dos to the harddisk, because I like the operating system installation method that without floppy disk drive and harddisk drive (edit: "harddisk" should be "CDROM'). In some statuations, to do this, there must be a dos OS, so the installation can began from dos.

I don't know what are bochs and dosemu,
but I'll search them by google just now.

Thank you.

Well, if you remove grub then you will need a boot floppy to load linux. You can download DOS bootable floppies from www.bootdisk.com