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.

Malik.. it is very interesting what you are with hiding the partitions. You could really take it a step further by using GRUB, the boot loader for most newer Linux distributions to activate and hide your partitions on demand with a simple boot screen.

Here is the partition screen using PQ Partition Magic 7.0 in WindowsME.
The only bootable partition in Disk2 is Windows 95.
Whereas in Disk1, the volumes MS-DOS_6-22 and Windows_ME are BOTH bootable. Have to use hide and seek here during installation, otherwise, things can go real bad.

Once all installations are complete, you can unhide ALL partitions. No problems here.

So under bios, when selecting which to boot, I select "D" drive to boot into Windows95. As for MS-DOS/WinME combination, first I set the BIOS to boot "C" drive. Then depending on my usage, I either choose the MS-DOS partition or WinME using the respective fdisk to change the "Set Active" option to either of these volumes.

I believe this is one of the advantages to have a later bios.

Another comment : The MS-DOS partition, which is shown as "K" drive will be automatically reassigned to C: drive when setting the partition to active.