Hi,
Here's a system for which I am in the process of evaluating the architecture design options in .NET

Server Application
1. Communicate through a socket connection to receive expected data
2. Persist the expected data on server objects
3. Listen on a COM Port to get the actual data from Scanners, and trigger a refresh on the client application

Client Application
1. Access the server object to retrieve the expected data
2. Receive a periodical trigger from the server to refresh screen with actuals.

The architecture design options with the pro(s) and con(s) is the objective. The 2 challenges are 1) Persisting Data and 2) Server/Client Communication

One option we can think about is Remoting for communication in distributed environment using singleton objects.

MSMQ can also be an available option. As for distributed environment, web service communication can also be an option.

What are the other feasible options we're left with? And how can a server application trigger off a client to make it appear event-driven?

Any inputs will be of great help.
Thanks,
Jemima.