Jon Hylands wrote:
> I can't find any Squeak images that implement #gcBiasToGrow:... Is that
> something you wrote, or part of some package I don't have?

It's been part of the VM for a long time but not exposed to the image in 
any shape or form. We added it to Croquet:

SystemDictionary>>gcBiasToGrow: aBool
	"Tell the VM to grow after tenures instead of running in a tight loop 
where it does IGCs over and over. For some weird reason the primitive 
takes an integer not a bool but oh well..."
	self primitiveGCBiasToGrow: (aBool ifTrue:[1] ifFalse:[0])

SystemDictionary>>primitiveGCBiasToGrow: arg
	"Tell the VM to grow after tenures instead of running in a tight loop 
where it does IGCs over and over. For some weird reason the primitive 
takes an integer not a bool but oh well..."
	<primitive: 'primitiveSetGCBiasToGrow'>
	^self primitiveFailed

Ditto for any others that may be missing.

Cheers,
   - Andreas