On Wed, Jul 02, 2003 at 11:27:22PM -0700, John M McIntosh wrote:
> >
> > Besides, signalling the event semaphore from the VM will only work if  
> > you
> > have a multi-threaded VM implementation which can process incoming UI  
> > events
> > in parallel to the VM's loop. If you don't, then you'll only get new  
> > events
> > every 500ms or so (depending on what your VM interrupt check counter  
> > says)
> > so not stimulating the input semaphore is not an option given all the
> > non-multithreaded implementations.
> 
> Well yes the mac os-x VM is a muti-threaded VM that has a separate  
> thread for the UI events. That's
> part of the carbon/cocoa event model. In fact the UI thread uses  
> pthread locking to deposit events onto the
> Squeak VM thread.

As an aside, the Unix VM with an X display could probably be made to do
this without resorting to pthreads. All external events are going to
originate from one of:
 1) external files
 2) sockets
 3) events originating from the X server (which arrive on a socket channel)
 4) OS signals

The first three can all be handled by the aio mechanism in Ian's VM, and
the forth can be handled in the obvious way. All four can therefore
trigger a Squeak Semaphore, and no VM level threads would be required.

Dave