The AdSCSI 2000 supports more than one internal drive, up to 6 drives iirc (or some combination of internal/external units no greater than 6). You need a 50-pin scsi ribbon cable with multiple connectors to attach more than just a harddrive. With scsi chains, termination of the last drive is key. Make sure you have set the jumper on the last drive only for termination. On an A2000, this usually is a cdrom drive in the 5.25" bay (or so on all the machines I've set up). Occasionally you need to put a passive terminator on the cable beyond the last drive for fussy controllers. The AdSCSI is a pretty simple controller, so just setting the jumper on the last drive should be okay. You should know that AdSCSI is a polled scsi card (i.e. it doesn't do DMA transfers), so performance isn't that great and ties up the cpu (on a par with old ide). You can use the DB25 external connector for external drives, again just make sure you properly terminate that end of the chain. You'll need a DB25 to Centronics external scsi cable(s).
