Adaptec AAA-130U2 Installation And Hardware Manual

Contents

Adaptec AAA-130U2 Installation And Hardware Manual Manual pdf 21 page image

2-7Installing the HardwareTerminate the EndsTo ensure reliable communication on the SCSI bus, terminators mustbe installed (or enabled) on the devices at the physical ends of eachSCSI channel. The devices between the physical ends of each SCSIchannel must have the terminator removed (or disabled).Terminating SCSI Channels on the AAA-131U2/133U2 RAID CardTermination on the AAA-131U2/133U2 itself is controlled via theSCSISelect™ utility. We recommend that you leave each channel onthe AAA-131U2/133U2 set to its default setting of Auto Mode (theterminators are enabled or disabled according to the SCSIconnectors in use). If you want to manually disable theAAA-131U2/133U2 termination setting, see Chapter A, UsingSCSISelect and Disk Utilities.Terminating SCSI DevicesOn most internal SCSI devices the termination setting is controlledby setting a jumper or a switch, or by physically removing orinstalling a resistor module(s). On most external SCSI devices,termination is controlled by installing or removing a terminatingplug (see Figures 2-14 and 2-15 on page 2-17). Read the device’s doc-umentation to determine how to enable or disable termination onyour particular device.The internal SCSI cables supplied in an Adaptec AAA-131U2/133U2kit have a terminator attached. If you have this type of cable, disabletermination on all internal SCSI devices connected to the cable. Ingeneral, we recommend that you terminate the internal cableinstead of terminating the SCSI devices. If you are using an externalarray enclosure, we recommend that you terminate the SCSI back-plane or install an active terminator on the second SCSI connectoron the rear panel instead of terminating the individual SCSI devices.If you follow these recommendations, SCSI bus termination will notbe affected when you remove or replace SCSI devices.Note: We recommend that you enable termination power onall SCSI devices in the system so that termination powerwill still be supplied if you replace one or more drives onthe SCSI bus.