CompuServe Messages

Hi, Tim! Well, this whole thing of SCSI-2 vs SCSI-1 is fuzzy at best, but from what I've gleaned from the book I bought this is what you need to know about compatibility, assuming the A2091 is essentially the same as my A3000 SCSI controller (built-in): 1) SCSI-2 Hard Drives all have the SCSI-1 commands standard, which means they will be "software-protocol" compatible with a SCSI-1 controller. If you later add a SCSI-2 controller, the extra features in SCSI-2 are then available. Using a SCSI-1 controller on a SCSI-2 drive presents no real problems, the only side effect might be that you are limited in the transfer rates (the drive may be slightly slower than if you had a SCSI-2 controller), which isn't really a factor for Syquest or ZIP drives. 2) A Syquest or ZIP drive is a removable hard disk, so it should have no problems with your A2091, assuming you have the proper driver. I think that for the Syquest you might need a utility called SCSIMounter or something like that, to make the Amiga aware when you swap cartridges. Otherwise, I think the setup is similar to setting up a regular hard disk using HDToolbox. On the ZIP drive, I read in CU-Amiga that Fourth Level Development has come out with a driver that lets the OS know when you swap cartridges. Dale Larson (IAM) may know more about this, as he distributes their products. This driver is sold with ZIP Drives in England/Europe. Those drivers would be needed if you had a SCSI-2 controller, anyway. 3) The external Drive needs to be Terminated. As of SCSI-2, there is an option for the drive to supply the +5v termination power, either to its own resistors, or the bus. I highly recommend that this be disabled (Bus supplies term power), usually set by a jumper or dip switches, so that no damage can be done to the drive or the A2091. Under SCSI-1, only the Controller supplies the termination power. Hope this helps… remember, I might be wrong about some of this… I hope others will chime in and point out any errors…Bottom line is you can use Syquests and Zips on a SCSI-1 controller without too much hassle – just be aware of the termination. — Dave