John,

> AH, well yes, but it seems we prim the event semaphore everytime we 
> want to get an event from the queue. Which makes the event semaphore
> mostly useless, other than keeping the EventSensor from spining to 
> look for null events.

Well, yes and no. It depends on what you're planning to do to make
Squeak passive. I can see at least three ways to do it, two of them
using the input semaphore and one of them not using it. It all depends
on how you'd go about integrating delays, I/O, and input events.

> Technically it would be nice for async VM to signal it, and not have 
> the Smalltalk second guess what the VM is doing. I'll try that, but 
> I'm not sure what value it adds. Other than saving a few hundred byte 
> codes and a primitive call everytime Morphic wants an event.

There's probably not a lot to gain.

Cheers,
  - Andreas