Technical data

Figure 2–7: Inserting Bus Node ID Plugs
MLO-004045
Bus Node
ID Plug
2.4.3.2 Labeling RF-Series ISEs for Systems with Multiple DSSI Busses
VAX 4000 Model 300 systems have two separate DSSI adapters built into
the CPU. Other systems may have more than one DSSI bus using the
KFQSA storage adapter. Using R400X expanders you can fill up to four
DSSI busses for a total of 28 RF-series ISEs. Each bus can have up to
seven ISEs (bus nodes 0–6). When there are devices on more than one bus
and the system’s allocation class is not zero, you need to program new unit
numbers for ISEs, as the unit numbers for ISEs throughout the system
must be unique. Instructions provided in a later step describe how to
program new unit numbers, overriding default values.
With devices on two or more busses and a nonzero system allocation class,
the ISE unit numbers 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 2–11.
Installation 2–15