Actually, I think he's asking Dragon if he has to change jumpers when specifying in BIOS to boot from the Slave drive first.
That would be no. If the BIOS allows it, you just tell it what sequence you want to use to detect a bootable drive. For instance, mine is HDD0, HDD1, CDROM which would search the Drive Master, then Slave, then CD.
If I set it HDD1, HDD0, then if the Slave is a bootable drive, it will boot from that, if not then it will boot from the Master.
A bootloader such as LiLo or NTLDR will give one a menu to choose which Operating System (OS) to boot from, and those OSes can reside on different hard drives (preferable, actually), which is what Dragon uses.