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Conference varese::basestar_open

Title:BASEstar Open Multiplatform Application Framework
Notice:Kit pointers: see topic 3
Moderator:VARESE::CORBETTA
Created:Tue Oct 02 1990
Last Modified:Fri Jun 06 1997
Last Successful Update:Fri Jun 06 1997
Number of topics:607
Total number of notes:1971

603.0. "B* Client reconnect" by MSAM03::VIJAYARAJ () Thu May 29 1997 17:45

    Hi,
    	We are setting up a BASEstar Open server running on Digital Unix
    with BASEstar Open Client for WNT V3.1 running on WNT Workstation,
    PC's. Our requirement is that, if the BASEstar Open server is rebooted,
    we want the BASEstar Open clients, to be able to recoonect to the
    server without manual intervention.
    
    	Is this possible ? Please advise !
    	
    	Thank you.
    
    Best Regards,
    Vijay
    
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603.1PossibleVARESE::ZOCCOLADeprimitElatosLevatAlexandriaStratosFri May 30 1997 10:5620
Yes, it is possible, building applications in the right way.

Let me explain.

BASEstar Client library is connection failure aware, that's to say it allows an 
application to be informed that the connection toward the server has broken and
the application can start a recovery phase via API.
For more information on this functionality, see API manual under "Recovering
applications on Client Nodes".

Nevertheless, remember that BASEstar operations are not stateless, that's to say
when a server goes down and restarts, the objects it was managing are no longer
available, so the recovery phase may need to recreate them.



		Redards.

			< Aldo >
603.2AlternativesMSAM03::VIJAYARAJMon Jun 02 1997 19:5327
    Can the following method be applied to achieve quite a similiar result
    ?
    
    Define a data point on BASEstar server, whose value is consistent
    changed from 1 to 2 and from 2 back to 1. At the client, use an
    application that supports BASEstar client for NT (e.g. Wonderware
    InTouch), and monitor the
    datapoint. If the datapoint value fails to change value for a duration
    of time (e.g. 1 minute) we assume that there has been a BASEstar
    server-client connection break (either because the server has shutdown
    or because the DDE bridge is down !). When this happens the InTouch
    application will start up an NT script program (program A).
    
    Program A will shutdown all applications on the BASEstar
    client station and trigger a reboot. Upon reboot the startup script,
    when starting up BASEstar client processes ensure that there aren't any
    error messages (indicating server-client connection problems). If there
    was any error messages during startup, the shutdown and reboot process
    is performed again. This carries on until a successful startup (without
    any errors) is performed.
    
    Please advise if the above is a viable solution.
    
    Thanks.
    
    
    Vijay
603.3??VARESE::ZOCCOLADeprimitElatosLevatAlexandriaStratosTue Jun 03 1997 15:2413

DDE bridge built-in recovery has been implemented to avoid all these user 
headaches.

Why are you planning such a solution ?

However, if this solution fits other needs of yours, you are free to implement 
it.



		< Aldo >