Connecting External SCSI Devices

External SCSI-2 devices connect to your system through the built-in single-ended Fast/Wide SCSI-2 port on I/O+ boards (except for the board in slot 1), or through FSBE/S, DSBE/S, SWIS/S, or DWIS/S SBus cards installed on I/O+ boards.

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Note -

The onboard SCSI-2 bus on the I/O+ board in slot 1 controls internal media tray devices. Therefore, the external SCSI connector on the I/O+ board in slot 1 must always have a terminator installed.

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Note -

The maximum combined length for a string of SCSI cables is 6 meters for non-differential cables. For differential SCSI cables, the maximum is 25 meters. When calculating the total length of a SCSI string, include external cables, internal cables, and printed traces. Table 2-3 lists internal measurements for the Enterprise servers.

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Table 2-3 Internal SCSI Lengths (Approximate)

Location	Internal Length
SBus+ I/O board	0.43 meter
Graphics+ I/O board	0.43 meter

For information on device addressing, priorities, and slot assignments, refer to "Rules for System Configuration" in the Sun Enterprise 3500 System Reference Manual, part number 805-2630.

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Caution -

Risk of equipment damage. Do not assign the same SCSI address to two devices sharing the same SCSI bus or SBus card.

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To connect an external SCSI device to your system:

1. Connect a SCSI cable to the appropriate SCSI-2 host on the I/O+ board.

   • For the I/O+ board in slot 1, this is an SBus card installed in an appropriate SBus slot.

   • For I/O+ boards in slots 2 through 5, use the onboard SCSI-2 port or an SBus card installed in an appropriate SBus slot. Figure 2-13 shows the location of the onboard single-ended SCSI connector on the I/O+ board.

   Figure 2-13 Onboard Single-ended SCSI Connector on the I/O+ Board

   
   

2. Connect the other end of the SCSI cable to the external SCSI-2 device.

3. Power on the system and test the server.