On Thursday, February 14, 2002, at 05:09 PM, Tim Rowledge wrote:

>
>> On Thu, 14 Feb 2002, Karl Goiser wrote:
>
>>> Aren't most modern operating systems and environments event driven?
> OSs are usually interrupt handling, UIs are typically non-interrupt
> event driven. Note however that nearly all of them (I have been assured
> in the past that Be OS is exclueded here) require you (as in the
> application) to poll for those events.

Mac OS X with Cocoa is also an exception.  Your app just sits there and 
you get bona-fide messages sent down the responder chain.  While it is 
theoretically possible to run the event loop yourself, it isn't really 
practical, which is why CocoaSqueak is two-threaded.  The encapsulated 
"event-loop" essentially sits waiting for Mach messages.  It also 
handles timed background 'processes' using timeouts on the waits (it 
could in theory send itself a Mach message at a specific time, but that 
would be somewhat pointless, if 'more pure').

Marcel