Expand Management Programming Manual

COMMUNICATING WITH THE EXPAND MANAGER PROCESS
Communicating Through SCP
6. If the request is directed to the EXPAND manager process
itself, that process responds to the request. If the request
is directed to the NCP or to $ZNUP, the EXPAND manager
process forwards it to that process, which in turn sends its
response back to the EXPAND manager process. Likewise, if
the request is directed to a line-handler process, the EXPAND
manager process forwards it to the line-handler process and
the line-handler process returns its response to the EXPAND
manager process.
7. The EXPAND manager process then returns the response to SCP,
and SCP returns it to the application.
8. Before terminating, the application closes the SCP process.
Usually the EXPAND manager process remains in the open state
after being opened by SCP. It will be closed if any file-system
error occurs or at the expiration of any timeout value.
CREATING THE EXPAND MANAGER PROCESS
The EXPAND manager process can be created either by a RUN command
from a command interpreter such as TACL or by a NEWPROCESS
system procedure call. After the EXPAND manager process has
been created, SPI-formatted requests can be sent to the EXPAND
subsystem through SCP.
It is recommended that the EXPAND manager process be created as
a NonStop process pair. Note that this process is a privileged
process.
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