>>there is really only a single thread of execution, if you need to have several >identical instance of a method to execute simultaneously, ytou need to use MTS >to manage multiple instances of the object.
>
>Nope. Wrong answer <s>...
>
>Just because VFP is single threaded doesn't mean it can't run concurrent requests. Apartment Model Threading allows for this to work by loading
>in essence multiple copies of your server into memory and running them
>side by side. They share a runtime, and they run in a single process
>but all their data is separate - stored in Thread Local Storage (TLS).
>In essence your VFP component is in fact running on multiple threads
>simultaneously (as evidenced by my examples).
>

I was aware that this happened with multiple interfaces, but not with a single interface referenced by multiple clients simultaneously. If this is the case, what manages thread affinity for a given client? I thought that MTS was needed to take care of the issue.

>The tool must support this by providing true local data for all instances
>and VFP does this in the MTDLL implementation of VFP. It did not provide
>the data protection in 6.0 though, although it was Apartment Model Threaded.
>Since data was not local, the blocking was forced on the runtime. SP3's
>MTDLL localizes all data and the blocking disappears.
>
>MTS doesn't help or hinder this process in anyway. MTS is just another
>multi-threaded client for a VFP COM object, just as IIS/ASP can be.
>
>A *true* multi-threaded component can run in a process's MTA (multi-threaded
>apartment) which is more efficient. A single copy of this component
>(data and code) can service all incoming requests because the component
>can run on any thread at any time. The component itself is responsible
>for being thread safe and isolating its data (typically via CriticalSections
>etc). COM doesn't need to fix up a special wrapper STA apartment for the
>object to run in first.
>
>MTA capable components can be very efficient, but IIS and MTS don't support
>them very well, so there's little benefit for them. MTA components make
>a lot of sense for ASP Application object components, but otherwise the
>benefits from standard MS apps is minimal.
>
>
>+++ Rick ---