Installation guide

Glossary–4
THROUGH-BUS
A mode of operation where all the ISEs in an SF72 enclosure are
connected to the same DSSI bus. In this mode, the DSSI bus is
terminated using an external terminator.
TMSCP
Tape Mass Storage Control Protocol. Application layer protocol that is
used by the host to perform tape I/O operations and I/O control functions.
TTM
Transition termination module. A PC board that provides connection
between the SF72 OCP and RF72 ISE, and also provides DSSI bus
termination when in split-bus mode.
UNIT NUMBER
Also called the MSCP/TMSCP unit number. Default value is the ISE’s
DSSI node ID. A unique value can be selected using PARAMS.
VAX DIAGNOSTIC SUPERVISOR
A diagnostic environment that allows access to DSSI tests and programs
in VAX 6000 series systems.
VIRTUAL CIRCUIT
A logical point-to-point link between nodes.
XBN
External block number. The blocks located in the external block area
contain the FCT. They are not visible to the host operating system.
XMI
Extended Memory Interconnect. The system bus for the VAX 6000 series
systems.