With my limited knowledge of SCSI standards, coupled with my first-hand knowledge of what have worked for me in the past, I can attest to the fact that as long as the drive is a 50pin drive, it's SE/30 compatible. In fact, you can take a new, ultra wide 80 pin driven and with the appropriate adapter, install it in you own SE/30.

However, I *have* found problems with large drives and System 7.1 and below. Seems like System 7.1 doesn't like large drives (partitions to be exact) in the gigabyte-range.