How to install FreeDOS in Linux dualboot with GRUB, not having cdrom or floppy drive
If you need instructions to do it the optimal way, scroll down.
The pioneer way
FreeDOS comes in form of .iso images. My laptop has no cd drive and installing from unetbootin'd install cd to flash didn't work (it booted from flash ok though), so i had to go creative. Here's what i did:
Repartitioned pendrive with xfdisk and installed FreeDOS on it
dd'ed dump back to pendrive
Made a free FAT32 partition on laptop
Booted FreeDOS pendrive on it
Then i tried to cp the fdos/ directory on new partition, but it hang up halfway through. So i booted Linux and happily copied the files over.
Set up grub to boot FreeDOS using chainloader
The optimal way
What you need for the task is:
Any FreeDOS bootable media. I recommend using unetbootin to convert one of FreeDOS cds (you actually need only base cd) to bootable pendrive. Alternatively you can try using sys-freedos-linux to make the partition bootable