Multi-Initiator Support; Configuration Rules - Sun Microsystems Sun Enterprise 220R Owner's Manual

The following figures provide a summary of the cabling guidelines.

Multi-initiator Support

The SCSI implementation of the system includes multi-initiator support: any
external host adapter on the bus can drive Termpower. This means that if the system
should lose power, the devices on the SCSI bus (except those powered by the
system) can continue to operate.

Configuration Rules

For fast/wide performance, you can connect up to 12 devices to the external SCSI
bus. For UltraSCSI performance, no more than seven devices may be connected.
Each device must have a unique target address (SCSI ID) in the range from 0 to 15.
You cannot assign target address 7 to any device; it is reserved for the host adapter
on the main logic board.
For UltraSCSI performance on the external SCSI bus, all cables used must be
UltraSCSI-compliant, and you must adhere to the following bus length restrictions:
For 1 to 3 devices, the maximum bus length is 3 meters (9.84 feet)
For 4 to 7 devices, the maximum bus length is 1.5 meters (4.92 feet)
86 Sun Enterprise 220R Server Owner's Guide • October 1999
System Non-Sun device
68 - 68
System Sun device
68 - 68
Sun device
68 - 68
Autoterminating
Sun device
68 - 68
Adapter cable
Autoterminating
Sun device
68 - 68
50-pin device
T
Terminator
68 -50