Comment #1 on issue 3322 by jannik.laval: [Kernel Dependencies]
ClassDescription>>#updateInstanceFrom:
http://code.google.com/p/pharo/issues/detail?id=3322mail from Mariano:
The problem is the class changes. If there are objects that or disk with an
image semgment, you want to load back the segment, update their instances
(of the class that changed), and then put them again on disk. To do this,
ImageSegment puts its code in updateInstancesFrom: oldClass
I don't know about announcements or SystemNotifier. If someone is already
notifying a class change, then ImageSegment could be just registered there,
be notified and wala, no dependency. But I am not sure if someone is
notifying or how to do it (to add it).