From:  Dean Swan at MITEL on 04/14/2000 07:52 PM

Mark,
     "Compact Classes" are not any different than "Uncompact Classes", except
that they have an abreviated "name" for use in object headers.  This allows
object headers of object which are instances of a "compact class" to fit in one
fewer word than the object header of "uncompact class" objects.  Depending on
your point of view, this is either a performance optimization, or an
obfuscation. (Has anybody actually measured the speed difference with and
without compact classes?).

     See "SystemTracer>>initCompactClasses", or select 'compact class' in a
workspace and pick 'method source with it' form the <Shift><BlueButton> menu (or
just bring up the workspace pane menu, and select 'more' then 'method source
with it' if you don't have a three button mouse.

                                              -Dean Swan
                                              dean_swan at mitel.com






"Mark Ferma" <squeak_sk at hotmail.com> on 04/14/2000 09:10:25 PM

Please respond to squeak at cs.uiuc.edu

To:   squeak at cs.uiuc.edu
cc:    (bcc: Dean Swan/Ogd/Mitel)

Subject:  Question/Compact Classes



Do You know what does "Compact Class" mean?

When I was looking at ObjectMemory description, I found this:
'If a class is in the compact class table, then this is the only header
information needed.'

Where I can read more about it? (compact class table).

Thanks.
      Mark
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