Technical data

Figure 2–11: Unit Number Labels
MLO-004237
Attach Unit
Number Label
10
0
as bus node 1, one storage assembly as bus node 2, and so on; you can
have only one storage assembly on bus 1 identified as bus node 1, one
storage assembly as bus node 2, and so on.
• By convention, the ISEs are numbered in increasing order from right
to left starting with 0.
NOTE: Bus node ID plugs are also used to supply node numbers on VAX
4000 model 200 and model 300 systems. The two DSSI host adapters.
2.5.2 Labeling RF-Series ISEs
VAX 4000 systems have two separate DSSI adapters built into the CPU.
Each bus can have up to seven ISEs (bus nodes 0–6). When devices are
added to the second bus (bus 1) and the system’s allocation class is not zero,
you need to program new unit numbers for ISEs on one of the busses, as
the unit numbers for ISEs throughout the system must be unique.
When both DSSI busses have ISEs, and the system’s allocation class is non-
zero, the unit numbers for one of the busses will not match the bus node
numbers on the bus node ID plugs. Unit number labels are provided with
each ISE to identify unit numbers for the user. The labels stick onto the
recessed label area on the ISE front panel as shown in Figure 2–12.
2–22 BA430/BA440 Enclosure Maintenance