Depending on various factors, it is very important to have termination on a SCSI Chain. Some machines like the IIfx are very persnickety about termination.

Some devices come with terminators already in them, finding out which ones you would need to open the up and check or look at their port sections and see if there is a switch for termination (like Zip/Jazz Drives do). When you find out which ones are terminated, put those terminated ones on the end of the chain.