>>  >     PhiHo.
>>  >
>>  >     P.S: Now I also understand what it means by Blue Plane and Pink
>Plane.
>>  >     Just wondering what colorful plane is Squeak now riding.
>>  >     (Are Grey or Black also considered colors ? )

PhiHo,

Isn't the whole point of Squeak's openness to put the user in the pilot's
seat, flying the plane of his or her choice?  I've used it on Boeing
Linux/PCs, Lear Macs and Airbus Windows machines, and I've heard of our
favorite Fledermaus merrily cutting loops and rolls on Piper PPCs and
Aeroflot Acorns.

Best of all, once a pilot's learned a few maneuvers, everything from paint
colors to engine noises is optional.  Admittedly, the developer's version is
something of a Sukharov - agile and highly capable but not for the faint of
heart - and many of us have a hard time going from the passenger seat to the
cockpit regardless of which plane we're on, but that's a purely personal
matter.

Gary "Crash" Fisher

"Any landing you can Walkback from is OK"

----- Original Message -----
From: "PhiHo Hoang" <phiho.hoang at rogers.com>
To: <squeak-dev at lists.squeakfoundation.org>
Sent: Sunday, October 13, 2002 7:07 PM
Subject: Re: Object Format


> Who's flying the plane ?
>
> Cheers,
>
> PhiHo.
>
> ----- Original Message -----
> From: "Alan Kay" <Alan.Kay at squeakland.org>
> To: <squeak-dev at lists.squeakfoundation.org>
> Sent: Sunday, October 13, 2002 7:51 PM
> Subject: Re: Object Format
>
>
> > Depends on who's flying the plane ...
> >
> > Cheers,
> >
> > Alan
> > -----
> >
> > At 6:47 PM -0400 10/13/02, PhiHo Hoang wrote:
> > >Hi Ian,
> > >
> > >>  You might also find the following useful:
> > >>
> > >>    http://www-sor.inria.fr/~piumarta/esug98/slides.ps.gz
> > >>
> > >>  starting around page 33.
> > >
> > >     Indeed, the whole document is very useful and interesting to read.
> > >
> > >     Thanks a lot, Ian.
> > >
> > >     BTW, were you teasing ?
> > >
> > >     On page 17 you mentioned a 'violently stripped' thingy. ;-)
> > >
> > >     Where can I find such a beauty ?
> > >
> > >     Of course, I would love to lay my hand on an 'eXtremely violently
> > >stripped' one.
> > >
> > >     The smaller the more fun. Size does matter ;-)
> > >
> > >     Again, many thanks for the explanation and the document.
> > >
> > >     Cheers,
> > >
> > >     PhiHo.
> > >
> > >     P.S: Now I also understand what it means by Blue Plane and Pink
> Plane.
> > >     Just wondering what colorful plane is Squeak now riding.
> > >     (Are Grey or Black also considered colors ? )
> > >
> > >
> > >----- Original Message -----
> > >From: "Ian Piumarta" <ian.piumarta at inria.fr>
> > >To: <phiho.hoang at rogers.com>
> > >Cc: <squeak-dev at lists.squeakfoundation.org>
> > >Sent: Sunday, October 13, 2002 4:47 PM
> > >Subject: Re: Object Format
> > >
> > >
> > >>  On Sun, 13 Oct 2002, PhiHo Hoang wrote:
> > >>  > - 4 bits object format
> > >>  >
> > >>  > What is this 4-bit 'object format' field.
> > >>
> > >>  It tells you about what the instance contains.
> > >>
> > >>  The top bit (bit 3) is 1 for byte objects, 0 for word/pointer
objects.
> > >>
> > >>  If the top bit is zero (words/pointers) then:
> > >>  Bit 2 is 0 for pointer objects, 1 for words.
> > >>  Bit 1 is set if there are indexable fields, 0 if there are none.
> > >>  Bit 0 is set if there are fixed fields (named inst vars), otherwise
0.
> > >>
> > >>  A "word" object (bit 2 set) that has neither indexable nor fixed
> fields
> > >>  (bits 1 and 0 clear) contains weak references and may have both
fixed
> and
> > >>  indexable fields.  (Unless the object contains only fixed fields
then
> you
> > >>  have to follow the class pointer and look in the class's
> "instanceSize"
> > >>  field to find out how many fixed fields are in it.)
> > >>
> > >>  If bit 3 is set (byte object) then bit 2 tells you whether it's a
> compiled
> > >>  method (set means it's compiled method).  Methods start with an
extra
> > >>  header word (look in class CompiledMethod to see what it contains)
> > >>  followed by zero or more real pointers (the literals of the method).
> > >>  After the pointers they turn into byte objects again.  Bits 1 and 0
> (of
> > >>  any byte object) are the number of bytes by which the size header
(or
> size
> > >>  field in the base header) is too large (since a bytes object might
be
> 0,
> > >>  1, 2 or 3 bytes short of an integral number of words long).
> > >>
> > >>  To summarise, if we consider the format as an integer from 0 to 15,
we
> > >>  get:
> > >>
> > >>  0     0000 no fields
> > >>  1     0001 fixed fields only (all containing pointers)
> > >>  2     0010 indexable fields only (all containing pointers)
> > >>  3     0011 both fixed and indexable fields (all containing pointers)
> > >>  4     0100 both fixed and indexable weak fields (all containing
> pointers).
> > >>  5     0101 unused
> > >>  6     0110 indexable word fields only (no pointers)
> > >>  7     0111 unused
> > >>  8-11  10xx indexable byte fields only (no pointers)
> > >>  12-15 11xx compiled methods: # of literal oops specified in method
> header
> > >>
> > >>  > Where can I find further detailed information about this 'object
> > >format'.
> > >>
> > >>  Browse class ObjectMemory in the image, and the object access
> primitives
> > >>  in class Interpreter.
> > >>
> > >>  You might also find the following useful:
> > >>
> > >>    http://www-sor.inria.fr/~piumarta/esug98/slides.ps.gz
> > >>
> > >>  starting around page 33.
> > >>
> > >>  Regards,
> > >>  Ian
> > >>
> > >>
> > >>
> > >>
> > >>
> >
> >
> > --
> >
>
>