Hi folks. Sorry for the cross-post, I am not sure if it is image or vm problem. If I implement this: SmallInteger >> initialize self addInstVarName: 'Zaraza'. I have the error: 'SmallInteger cannot be changed' This is because SmallInteger is in the ClassBuilder >> tooDangerousClasses and the error is in ClassBuilder >> name: className inEnvironment: env subclassOf: newSuper type: type instanceVariableNames: instVarString classVariableNames: classVarString poolDictionaries: poolString category: category unsafe: unsafe Now....since this is Smalltalk, I can just comment something, continue, or any other kind of hack so that I can add class variables to SmallInetger. For my CompiledMethod proxies stuff, I am using SmallIntegers and I have some crashes (one is due to a corrupt heap and Eliot said something about sizes)...I wonder if this is related to this...So the question is: is really SMallInteger a too dangerous class so that it cannot be changed? not even adding a class variable??? does the VM assume that the class SmallInetger has a fixed size? if true, where? Thanks in advance Mariano