1–6 Model 2100 and 2200 Ultra SCSI Controller Enclosures User Guide
Ultra SCSI Buses
Array controllers receive data from a host, process this data, and through ports, distribute
the data over single-ended, 16-bit, Ultra SCSI buses to the storage enclosures. Each bus
has 16 possible SCSI bus addresses (IDs): 0 through 15. Every node on each bus must
have a unique SCSI bus ID. Both array controllers interface with all I/O modules, where
very high density computer interconnect (VHDCI) cables connect the enclosure to the
storage enclosures.
The following addresses are reserved for the array controllers:
■
SCSI bus ID 7 — always used by Controller A, initially assuming primary controller
responsibilities in all configurations. No other device on the bus can use this address.
■
SCSI bus ID 6 — always used by Controller B, initially assuming redundant controller
responsibilities. No other device on the bus can use this address.
Communication Ports
One communication port adds functionality to the enclosure— the serial port (see
Figure 1–4,
1). This port is used for power monitoring activities and uses a 10-pin RJ45
cable connector.
Figure 1–4. Communication port location
1
Serial port
CXO6868B
1
