Interesting.
Though some do not prefer it, I always try not to dual boot. Instead I always prefer to create separate partitions for different OS. I try not to mix two OSs in the same partition and then dual boot.
For example, I just finished setting up my latest HDD Multi-OS configuration using two hard drives. Please bear in mind that this particular "classic" system is based on a PIII 1GHz Socket 370 based system. So the BIOS will be relatively newer.
One HDD is a 80GB drive, the other 40GB.
OS: MS-DOS 6.22
On the 80GB HDD, I first used FDISK to delete all partitions. Then started creating.
It recognized only the first 8GB of the total space. (That comes to 10% of the actual capacity.)
I let it create the first "Primary" FAT16 partition and set it active. Then created extended partitions in the rest of the space. It created upto 4 drives by using FDISK - C,D,E, and F.
Then I used Partition Magic 7 (PowerQuest) to create a FAT32 partition in the rest of the space. Then I "Hide" the FAT16 primary partition to prevent installation errors of other OSs. I then set this partition Active. Installed Windows 98SE in this partition. Booted properly into Win98SE without problems.
To use back the MS-DOS 6.22, I use Windows 98's FDISK to set the dos partition active. I've created a ms-dos shortcut in w98 to do this.
So when I want to switch back to Windows98, I set the the FAT32 partition (which is showed as Non-Dos Partition" under dos 6.22's fdisk) active.
This method will prevent manipulation of windows98 files by dos programs like defrag, since ms-dos 6.22 "can't see" the FAT32 partitions.
The other drive has Windows 95 currently. Planning to install Windows2000 in another partition.
You need a thrid party partitioners like partition magic for optimum management of the partitions.
And you need to play around with the partitons by playing "Hide-And-Seek" to make things install smoothly in the beginning. Otherwise, especially Windows 95 will be whining not to install it! 😉
UPDATE: Also, look for the HDD specs on the drive label itself and enter this info into the BIOS manually.