Functions and features, Path, Section 8 – HP NonStop G-Series User Manual
Page 125: Control path
DSM/Tape Catalog User’s Guide — 520233-008
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Storage Server Interface (SSI) to the
Tape Library Control Path
The Storage Server Interface process ($ZSSI) is the interface between the automated
cartridge system library software (ACSLS) that manages the storage and movement of
tape cartridges for tape libraries and the NonStop Kernel tape management process
$ZSVR.
$ZSSI translates and routes messages between the $ZSVR process on the NonStop
Kernel and the Client Server Interface (CSI) process on the ACSLS library server.
$ZSSI communicates with the CSI using RPC over TCP/IP and communicates with the
$ZSVR process through $RECEIVE. $ZSSI is used only by $ZSVR. Errors from the
tape library are returned to $ZSVR and logged in the EMS event log.
There is a one-to-one correspondence between $ZSVR and $ZSSI. $ZSSI is started
only by $ZSVR. $ZSSI is a persistent process because $ZSVR starts it. If $ZSSI stops,
$ZSVR automatically restarts it. $ZSSI is not a NonStop process; $ZSVR handles the
NonStop logic. Only $ZSVR sends messages to $ZSSI. There can be only one $ZSSI
subsystem on a node.
Functions and Features
The $ZSSI subsystem communicates through RPC over TCP/IP with the CSI software
component of the ACSLS library server software.
Request messages supported by $ZSSI are limited to those required by $ZSVR in its
support of the tape library. Support required by $ZSVR includes translating requests
and responses to these commands:
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