Technical data

Appendix B
Programming Parameters for DSSI
Devices
This appendix describes the console mode procedures for setting and
examining parameters for DSSI devices.
NOTE: Before you reprogram DSSI devices, you should have a good
understanding of DSSI architecture and VAXcluster software operation. If
you do not have that understanding, you should read the VMS manuals
listed in Appendix A or call your Digital service representative.
Two types of DSSI storage adapters are available for VAX 4000 systems:
an embedded DSSI host adapter, which is part of the CPU, and the KFQSA
storage adapter. The KA660 CPU has one embedded DSSI storage adapter:
bus 0.
Each storage adapter provides a separate DSSI bus that can support up to
seven DSSI devices (six DSSI devices for a dual-host configuration). The
adapters make a connection between the CPU and the requested device
on their respective DSSI bus. Each DSSI device has its own controller
and server that contain the intelligence and logic necessary to control data
transfers over the DSSI bus.
B.1 DSSI Device Parameters
Six principal parameters are associated with each DSSI device:
• Bus Node ID
• ALLCLASS
• UNITNUM
• FORCEUNI
• NODENAME
• SYSTEMID
Programming Parameters for DSSI Devices B–1