It actually got all its data over SCSI. I suppose its
main application was
the
very oldest compact Macs which didn't even have
any PDS slot.
The very oldest Macs didn't have SCSI ports... However, a company
called Dove had a board that plugged into the ROM slots, and into
which you then placed the ROMs, that provided a SCSI interface for
the Mac 512k/512ke. They also had a memory board that had the way
of interfacing to the main board... it had funny-looking sockets
that "clamped" down on top of the existing DRAMs and which provided
enough to bring a 128k Mac up to 512k or a 512k Mac up to 1MB. I
still have both boards...
-dq