40.68 and 40.70 exists for both A4000 version (desktop & tower)
difference between 40.68 & 40.70 is a different version from the scsi.device
(40.70 scsi.device where reported to make more problems with some drives, thats the reason for shipping 40.68 instead 40.70)
difference between "tower" & "desktop" is the missing workbench.library (replaced by wb.find and library outsourced to disk) and the additional ncr_scsi.device for the scsi.controller
