Tom,
Well the main service-like benefit of COM that most people want is being able to run the application without a logon. Another is running without an interface.
Most of my experience with this is running web VFP application servers which, of course, must work without a logon and have no interface. It's similar to communications programs like yours since you have one app (a C++ .exe or ISAPI .dll in our case) communicating with the VFP app server. I actually first did this with DDE. It worked and was fast but didn't have a lot of the benefits of COM.
I really love how smoothly a VFP mtdll works and scales so effortlessly creating and re-using threads as needed - if anything I'd say your app may need less memory, but, definitely try it out to see how it works for your situation.
>Claude,
>Thanks for the reply. We are considering using COM server in place of some of the DDE message passing. I am interested in what you think are the benefits of using COM that would be the same as Win2000 Service?
>
>One example of our system is a program that communcates with serial devices. When it gets a query from the serial device, it then uses a DDE Request to pass the query to a program that validates the query and then returns either an error message or some data. When the communication program gets the data back it transmits it via the serial port to the device. There are several communication programs running at the same time, all of which send DDE requests to the same DDE server.
>
>We were thinking that the DDE Server could be setup as a COM server and provide the same functions. Having never used COM before, we were wondering about which of the different methods would be best in this case. I read about in-process and out-of-process, but then I see "as DLL" or "as EXE" in the Build options. It is somewhat confusing at this point, having nver tried it. We were wondering also whether this method would require a whole lot more RAM. Many times we have 8-10 communication programs linked to the one DDE SErver. If we used COM would that require 8-10 times as much RAM as the 1 DDE server setup?
>
>Thanks.
>Tom
>
>>Tom,
>>In addition to what Sergey said, I would also consider whether a VFP COM server might work well (either .exe or .dll) in your situation. VFP COM servers have most of the basic benefits of Windows Services...
>> >We are moving a system from Win98 to Win2000 Pro. The system has several programs that run in the background accepting and sending data via DDE. These programs currently have a visible window but htere really is no purpose for the window other than to close the program, which is almost never done.
>>>
>>>So my question is, How can we set these programs up to as a service in Windows 2000 Pro? That way they can still be easiliy started and stopped but do not clutter the desktop or task bar.
>>>
>>>Thanks,
>>>Tom