HP 9000 Series Service Manual page 463

HotSwap Disk Bay (D Class Only)
Address Switch:
The fourth position is labeled "ADDR. 12-15" — "ADDR. 8-11". The lower four module
positions in a Model D3xx system will be either 12, 13, 14, 15 or 8, 9, 10, 11. In the Model
D2xx system optional HotSwap module, the second disk module position will be either
12 or 8. The default setting is "ADDR. 8-11".
Appendix C C-9