The SCSI FAQ (Frequently Asked Questions) is an excellent source of information. It is posted in comp.periphs.scsi on Usenet during the first week of each month. In addition, a recent version can be obtained via anonymous ftp from:
Note: the gfield directory will not show up using DIR, but it's actually there. Just CD to it.
OR rtfm.mit.edu: pub/usenet-by-group/comp.periphs.scsi/comp.periphs.scsi_FAQ_part_*
OR via the World Wide Web (WWW):