I'm being asked about how best to seperate the business logic from a 'vintage' application.

This application runs standalone for some clients, networked for others and (of course) we'd like to migrate it to the web. It happens to be a VFP application (currently 5.0, I think), which grew up from a FPDos 2.6 application (if not earlier).

The business logic is volatile (well, maybe it changes once or twice a month) and it's modified from a central location. I'm not sure how much data is transferred in a typical transacion yet. Reliability is a major factor.

I'm told all current users have full-time internet connectivity. I'm not yet sure if we can make this a requirement for future users, but my gut feeling is that we can.

Soo... they're thinking along the lines of a COM object they can have running on the client machine for single users (updated with new business logic through an updater) doing the calcs for them - with the COM object on a server for our networked clients, and another copy of the same COM object running on the web server for the yet-unborn web version of the application. I have little experience with COM, but am never afraid of learning new stuff. I know that D-COM is a dead-end and difficult to configure.

I'm thinking a web service might be best - assuming we can keep the servers up and running in a reliable fashion. Depending on the nature of the data, I may have it either do the calculations real-time or just send the data from pre-built lookup tables which are refreshed whenever the business rules change. If the data set is large, we may have to go to SQL server but I have not investigated the licensing costs of doing that in this scenario.

I'd like some feedback! Is COM a tachnology that has outlived it's usefulness? Is it appropriate for these three distribution types? Can I make a web service with a pair of load-balanced servers as reliable as a standalone FP 2.6 application? Is MS-SQL the right back end to use for this, or should I consider something with more reasonable licensing terms?

TIA...
Michael