Hello,
OS X has always been a bit IFFY on SCSI support... I have a G3 powerbook, the Lombardi, and certain things on SCSI do not work, and certain things do work. I typically go into OS 9 if I need to do SCSI work.
Will your iBook load OS9? If so, give it a try. Your Jazz might work properly.
If memory serves, a Jaz removable disk held 1 GB of data or so.
Christian