They're essentially floppy disks but with platters instead of, well, floppy disks.

Here's a manual for the 1300/2300 model, dunno if it'll apply to yours.  It does have 4 dip switches for various options.

http://www.fujitsu.com/downloads/COMP/fcpa/mo/discontinued/dynamo-x300-scsi_user-manual.pdf

I didn't know that you can toggle it between MO mode and HDD mode.  The difference is that in HDD mode it'll show up as a SCSI HDD instead of removable media.  Pretty cool.