On Jan 31, 2016, at 12:49 PM, Chris Muller <asqueaker at gmail.com> wrote:

>>> I guess the distinction between “Kernel” and “System” isn’t quite clear to me.
>> 
>> I guess, for me, Kernel contains those things that are essential to a
>> running Smalltalk image. System contains stuff that's generally useful
>> to most things - most, but not all.
> 
> I've long thought that we'll eventually move Array, OrderedCollection,
> Set and Dictionary to Kernel so that Collections could be unloaded...

The inheritance relation won't let you do it.  Collection would have to be in Kernel and that's completely wrong.  And one can't represent Smalltalk programs without at least Kernel Numbers & Collections cuz all literals are either numbers or collections.  So it is a pipe dream to be able to unload these.

It might be nice to split Numbers into Numbers-Kernel and Numbers-TheRestOfTheCoreLibrary to distinguish between those numbers that can be literals and those that aren't, but then you'd have to add Numbers-Base to hold the superclasses of large and small integers and the floats up to and including Number.  And of course similarly for Collections.  But it's pain for little  gain.  There are other levels of organization (such as implement its of #isLiteral) that make the finer grain structure visible.