2-3Installing Your ControllerWide devices allow data to be transferred at twice the rate ofNarrow devices. The Wide bus is backward compatible withNarrow devices, allowing both types of SCSI devices to be used withthe same controller. The Narrow interface is still used with someSCSI devices, such as tape and CD drives.LVD and SE DevicesAttaching a single-ended (SE) SCSI device to an LVD bus causes thebus to slow down to Ultra SCSI speed (20 MHz) for all devices.Note: Adaptec RAID controllers cannot be used with olderSCSI 5-V differential (DE) devices.SCSI CablesAdaptec recommends you using Ultra160 SCSI devices and goodquality LVD SCSI cables, which can be purchased from Adaptec, atwww.adaptec.com, or other suppliers.SCSI Device IDsThe SCSI specification allows up to 7 SCSI devices (and a controller)to be connected to a single 8-bit SCSI bus. A Wide SCSI bus cansupport up to 15 devices and the controller.All SCSI devices, including the controller, must be assigned a uniqueSCSI ID. SCSI IDs, which are typically set using jumpers or switcheson peripheral devices, can be assigned any number from 0 to 7 for8-bit SCSI devices or 0 to 15 for Wide SCSI devices.Set the SCSI ID of each SCSI device attached to the controller to aunique ID number between 0 and 6. The Adaptec RAID controller isset to ID 7 by default (most SCSI controllers use ID 7). Wide SCSIdevices can also use SCSI IDs 8 through 15. SCSI IDs can only beduplicated on the same controller if the devices using the same IDare not attached to the same bus.
