After aborting when I received a low space notification, some code using 
a WeakArray stopped working because FinalizationLock was waiting 
forever.  Apparently some process had taken the semaphore and never 
signalled, so I had to manually signal to get things working again..  Is 
this a symptom of some fixable bug or just unavoidable?  Could we 
#ensure: something that would stop things from getting into this state? 
  This isn't an area of Squeak I'm hugely familiar with and I don't 
really have time to look into it further right now, but I'm just 
wondering if this immediately brings any ideas to mind..

Cheers, Andrew