SCSI Computer Devices
Though most people won't run into SCSI devices when dealing with computers, it doesn't hurt to know how to work with them.
Unlike IDE which can only have 2 devices on each cable (master and slave), SCSI can have many devices on a cable in a daisy chain. Each device has to have a unique number assigned to it (there can't be any duplicates). How do you assign your SCSI device a number? Use the jumpers. On the back of all SCSI devices there should be a set of jumpers (like regular IDE devices). Read the manual to see exactly which ones are which, but each set of pins should have a certain value and the values should go in order like this: 0,1,2,4... You can put more than 1 jumper on, so if you want to assign a device as 3, jumper both 1 and 2.
Keep in mind that hard drives usually are lower (0s and 1s) than other things. Also remember that SCSI devices are daisy chainable, so the end of the cable needs a terminator.