Installation guide

Storage Architecture Overview A-5
On both CI and DSSI, all nodes directly connect to each other. The DSSI
bus requires electrical terminators at both ends to ensure signal integrity
because it is DC-coupled (the CI bus does not require physical termina-
tion).
Logically, each DSSI bus is equivalent to a small CI with its Star Coupler.
The RF/TF devices on the DSSI are functionally equivalent to a combina-
tion of HSC and RA/TA devices on the CI. Like the HSC, each ISE control-
ler can communicate with multiple VAX 10000 hosts on the DSSI and or-
der disk seeks. ISEs do not have to share an HSC like CI devices, so each
additional ISE linearly increases I/O throughput and bandwidth.
DSSI can be implemented in single- or multi-host mode. In single-host, one
system has access to integrated storage elements (ISEs) across the DSSI
storage bus. In multi-host configurations, the systems remain functionally
independent while their common DSSI storage bus, together with
VMScluster software, makes ISEs available to each system, providing mul-
tiple data paths for access to ISEs.
For more information:
KFMSA Module Installation and User Manual