My problem conversion was a new G5 dual core 2.3 with older scsi Epson Expression 1600 flatbed and Polaroid 4000 slide scanners. The ATTO express PCI card is ~$450 with new LaserSoft software D~$400 is too much. I tried a Ratoc firewire/ultra scsi converter (FR1SX) ~$90. Connected the Ratoc to 400 firewire port on the G5, used internal termination on Epson, and Epson scan software that did not work previously with firewire on my old G4 dual 500. Turned on scanner, Ratoc light went on, turned on G5, started Epson scan and all looks go. I do not have to use Twain with Photoshop but can scan alone with Epson. I will also try Hamrick VueScan later for the Polaroid scanner. Also the speed of the Ratoc seemed like the old scsi --fast!!!!!!! Yes, SCSI still works great.
best, nrb