Grant, you are right, sorry for mistaking this so easily: I now looked it up (felt ashamed :-) and here it is (humorously from a sun site *g*)
http://sunsolve.sun.com/handbook_pub/Devices/Disk/DISK_SCSI_Overview.html SCSI-1 Narrow 8-Bit Data Bus Single Ended (SE) or High Voltage Differential (HVD) Asynchronous Transfer Rate up to 2.5Mbytes/sec Synchronous Transfer Rate up to 5Mbytes/sec Fast SCSI / SCSI-2 Narrow 8-Bit Data Bus Single Ended (SE) or High Voltage Differential (HVD) Asynchronous Transfer Rate up to 5Mbytes/sec Synchronous Transfer Rate up to 10Mbytes/sec Fast and Wide SCSI / SCSI-3 / SCSI-3 SPI Narrow 8-Bit or Wide 16-Bit Data Bus Single Ended (SE) or High Voltage Differential (HVD) Asynchronous Transfer Rate up to 10Mbytes/sec Synchronous Transfer Rate up to 20Mbytes/sec (adaptec 2944 is a differential scsi pci controller) (adaptec 2940 is not differential) Fast-20 SCSI / Ultra SCSI Narrow 8-Bit or Wide 16-Bit Data Bus Single Ended (SE) or High Voltage Differential (HVD) Asynchronous Transfer Rate up to 20Mbytes/sec Synchronous Transfer Rate up to 40Mbytes/sec Fast-40 SCSI / Ultra-2 SCSI / SPI-2 Narrow 8-Bit or Wide 16-Bit Data Bus Low Voltage Differential (LVD) Backwards compatable with Single Ended (SE) Asynchronous Transfer Rate up to 40Mbytes/sec Synchronous Transfer Rate up to 80Mbytes/sec i have Adaptec 2940uw2 controllers with "normal" single ended uw2 disks and also normal single ended wide scsi cables internally.i mistakenly thought of "ultrawide" with 40MB/s but it is (as you stated) uw2 single ended with 40mb Fast-80 SCSI / Ultra-3 SCSI / Ultra-160 SCSI / SPI-3 Wide 16-Bit Data Bus Low Voltage Differential (LVD) Backwards compatable with Single Ended (SE) Synchronous Transfer Rate up to 160Mbytes/sec Fast-160 SCSI / Ultra-320 SCSI / SPI-4 Wide 16-Bit Data Bus Low Voltage Differential (LVD) Backwards compatable with Single Ended (SE) Synchronous Transfer Rate up to 320Mbytes/sec thanks again for clearing this out, next time i promise not to sleep at hardware basics school again :-) bye, Alex