COM+ uses a thread-pool per server application, and the size of the STA thread-pool is approximately 10 threads multiplied by the number of CPUs. You can increase/decrease the size of the thread pool—see Microsoft Knowledge Base article Q303071.
Also, under plain old MTS, which a vfp mtdll will use unless it's running under Low Isolation, there's a simple registry setting that determines how many threads are allocated for COM objects running in the mts process. This defaults to 25 x [# of cpu's]. So on a dual-proc server, you would have (25 x 2) 50 threads allocated by default, and you could adjust this setting yourself by going into the registry and changing the cpu multiplier from 25 to whatever.
Even ouside of COM+ and MTS, you could use the AspProcessorThreadMax property if calling from ASP or ASP.NET.
You're implying that this technology is hard to control or somehow dangerous and it's just not true...

>>You can limit the number of threads used by using COM+. COM+ also allows more scalability when there's the need to put the DB on another server.
>
>I am not aware of that. How exactly? If you're talking about object pooling you realize that this doesn't work with VFP and STA components as it requires re-entrant objects.
>
>+++ Rick ---