Installation guide

Each DSSI bus has a limit of eight physical addresses: one, two, or three
adapters (KFMSAs) and from one to seven ISEs (RF disks or TF tapes).
Each ISE has a controller in the physical (tape or disk) drive which uses
the mass storage control protocol (MSCP) or tape MSCP. ISEs are located
in a VAX 6000 cabinet, a VAX 4000 Model 300 cabinet, or an SF2xx storage
cabinet.
Each connection has an initiator and atarget node. Any node on the bus can
act as either an initiator or a target. The actual communications are limited
to two nodes at a time. Arbitration mechanisms accommodate multiple
dialogues on the DSSI bus.
The ISE receives a complete packet of information requesting a task to be
done. The controller interprets the packet and performs the task without
any further communication from other DSSI nodes. The controller has a
command queue and handles access requests. It can start and monitor an
internal diagnostic, and provide status of the storage element.
VAX 6000 DSSIsubsystems supportRF72 andRF73disks, TF85 tape drives
in cabinet, and TF837 and TF857 tapes in SF2xx storage cabinets.
FOR MORE INFORMATION
Primary reference: SF2xx Storage Array Installation Guide
Secondary references: VAX 6000/SF2xx Embedded Storage Installation Guide
SF7x Storage Enclosure and SF2xx Storage Array Cabinet Ser-
vice Guide
TF85 Cartridge Tape Subsystem Owner’s Manual
DSSI VAXcluster Installation Guide
Connecting to a DSSI Subsystem 3–13