You mean Multi Boot?

How to create a multiple-boot system in Windows XP
http://support.microsoft.com/kb/306559

You may also use a third party product (boot manager) to do something
similar.

Or even a low-tech solution of defining hard drives in the BIOS only when
you want to boot from one or the other.

I've heard you can do it with floppies and CDs, anyway (and doing this
might be better for you than devoting a whole drive to it.. though maybe
not).  First i'd google "DOS 6.22 boot disk" and see what you find...

Suppose! If you have one hard disk and you want to install an operating
system on it then your OS will only look for Primary Partition. That doesn't
matter that where the partition is? Either it is on Master or Slave, Primary
or Secondary.

If you have more than one hard disks and you want to install another OS on
your second hard disk then you must care of many things. The very first
thing: is your current operating system is supportable with new one for dual
booting.

If no, then you have to create 2 Primary Partitions for each HDD and use a
third party softwares like XOSL [Extended Operating System Loader] which can
create a menu for both operating systems and can active the Primary Partition
for the drive you will use.

But all these things need a advanced knowledge else you can make your PC
unstable.

Let us know!

Use a third party boot manager like BootItNg by Terabyte Unlimited
http://www.terabyteunlimited.com/bootitng.html or XOSL
http://www.ranish.com/

John

Though you could install Dos6x on a fat16 partition
either with a boot manager or else just booting to is with a floppy...
You can run "command" in XP to give you a virtual dos.

NOTE: Some basic programs rely on CPU timing loops
so will may not run on your new machine with a fast CPU.

I was able to get some qbasic stuff to work after I modified the timing
loop.