RSC/MP Installation and Configuration Guide

Best Practices Guide Host Home-Terminal Considerations
Host Home-Terminal Considerations
In many NonStop installations, it is common practice to connect to the host through
Telnet or X-Windows sessions on a workstation. Howeve r, you should not use such a
session as the home terminal for a TDP, PIPEMAN, or NIF process.
By nature, Telnet sessions are transient. They are created when a user logs onto a
NonStop server and are deleted upon logout. Home terminals, on the other hand, are
more permanent because they are required to exist for as long as the processes using
them exist. In particular, many NonStop processes, including the RSC/MP host
components, require that the home terminal exist at the time the processes are
launched; otherwise the processes will ABEND upon startup.
For example, if a TDP is configured to run as a process pair, and this pair is launched
from a Telnet session, both the primary and backup instances of the TDP will be
assigned the Telnet session as the home terminal. When the operator logs out, the
Telnet session is closed and the TDP continues running. If the CPU containing the
primary TDP fails, the backup process takes over, becoming the primary process.
When the failed CPU is restored, the TDP attempts to start another backup in that
CPU. The new backup is assigned the original Telnet session ID as the home terminal.
However, since that Telne t session has been deleted; the backup TDP process
ABENDS. The primary process is notified of the ABEND and attempts to start another
backup process, causing an endless cycle.
To avoid this situation, when starting Piccolo from a Telnet session, use the IN, OUT
and TERM options in the [PIPEMAN] section of the Piccolo configuration file to specify
a permanently configured device. For example,
[PIPEMAN]
IN=$CONSOLE
OUT=$CONSOLE
TERM=$CONSOLE
Similarly, modify your STARTRSC file to specify a permanent device as the home
terminal of the TDP. For example,
run [rscsys].tdp /name $xrsc, nowait, in $0, out $0, hometerm $0/
HP NonStop Remote Server Call (RSC/MP) Installation and Configuration G uide — 52235 8- 013
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