About SCSI on your Amiga

PLEASE READ THIS CAREFULLY IF YOUR AMIGA HAS A SCSI CONTROLLER!!!

SCSI termination is a weird thing, even when drives are not terminated properly they may work fine. However, all of a sudden they may just stop.

This is how SCSI works: SCSI controllers are a device in themselves, this means they occupy a device number. Usually this is either 8 or 0, check the manual (most controllers use 8).
If you have a conflict with your devices, they won't work properly... make sure none of your device numbers are the same.
As a rule of thumb, your drives should always be in sequential order. That is, the boot drive is device number 0, and every drive after that is sequentially higher (that's not to say that they have to be in regular order 1..2..3..4, they should just be sequentially higher, as in 0..1..4..5..7). Your last drive and ONLY your last drive should be terminated.

For those who don't know what "terminated" means, it means that one of the drives has terminating resistor packs on it.
All SCSI drives have some sort of terminating resistors, they are small little electronic components on the drive, or for external devices are blocks that plug in directly to the free port on the last drive.

There are usually more than 1... usually 2 or 3 and located either on the underside of the drive or near the SCSI connection. They can be tricky to find since sometimes they are inserted to an electronic component that looks similar to a small IC. Your drive's manual should detail where to find them. Only the last drive on the chain should have a terminator!

External drives with a pass-through connector, are terminated with external terminators, they are usually a big gray block with a connector that fits onto the pass-through connector.

What about drive jumpers? As a general rule of thumb, SCSI drive jumpers should not be changed from their factory settings. If the drive is connected properly and it still doesn't work, contact the manufacturer by phone or by web, before changing jumpers.

In the words of Mr. Dave Haynie (one of the more famous Amiga engineers from the Commodore days) "Even if it says SEX and FREE BEER, never change a jumper you are not familiar with!"