jchludzinski at worldkey.net wrote:

> BUT when I try the exact same code on 2.9a - it freezes.
> 
> Has anyone else seen this?  Another engineer I work with has hung
> Squeak 2.9a by simply saving the image.

Have you tried forking the threads at a priority lower than the 
UI (i.e. use "forkAt: Processor userBackgroundPriority" instead of fork)?

This may tell you something.

A process running at or above the priority of the user interrupt handler
can keep Squeak from responding to a user interrupt.

A process running below that, but at or above the priority of the
UI, can keep you from being able to interact with the notifier that
the interrupt handler brings up.

-- 
Ned Konz
currently: Stanwood, WA
email:     ned at bike-nomad.com
homepage:  http://bike-nomad.com