secondary FDC on PC with MS-DOS?

Hi, I am building a test station using an old 486 ISA only computer to test floppy disk drives and old ST-506/ST-412 style hard disk drives. The computer seems to work OK and has a Western Digital ST-506 MFM hard disk controller with a FDC on the card (IO address $1F0). To help with testing floppy drives, I thought I would add a secondary FDC however that is turning out to be much more difficult than I planned. It seems there are drivers required to make floppy drives attached to the secondary controller appear as drive letters under MS-DOS. I searched around a bit and found SDRIVE.SYS which refuses to acknowledge any of the other FDCs I place in the computer at the secondary address (IO address $170). There are some references to a DC2.SYS program but I cannot find it anywhere online. http://www.seasip.info/VintagePC/floppies.html Does anyone know how to add multiple FDCs to a PC so I can have multiple floppy disk drives? Of course, the Compaticard IV would be nice but those are very expensive and almost unobtainable these days. I have a Compaticard I which "sort of" works but the drive gives errors every other time I access it. Thanks in advance for any help -- especially if someone could send me or tell me where I could find the DC2.SYS files. Andrew Lynch