User guide

C
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.
On VAX 4000 Model 105A/106A systems, an embedded DSSI adapter on
the KA53/KA54 CPU provides the interface between the CPU and the DSSI
storage devices.
The KFDDA-BA daughter card adapter provides a DSSI bus that can
support up to eight nodes, where the adapter and each DSSI storage device
count as one node, hence each DSSI adapter can support up to seven DSSI
storage devices (six DSSI storage devices for a two-system DSSI VAXcluster
configuration; five DSSI storage devices for a three-system DSSI VAXcluster
configuration). The adapter makes a connection between the CPU and the
requested device on the 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.
Note
On some sytems, an optional DSSI daughter card (KFDDA–AA)
provides two DSSI interface adapters, so there are two DSSI buses
with the same specifications.
Programming Parameters for DSSI Devices C–1