On Wed, Aug 19, 2009 at 6:56 PM, Igor Stasenko <siguctua at gmail.com> wrote:

> 2009/8/20 Eliot Miranda <eliot.miranda at gmail.com>:
> > Hi Igor,
> >
> > On Wed, Aug 19, 2009 at 6:00 PM, Igor Stasenko <siguctua at gmail.com>
> wrote:
> >>
> >> 2009/8/20 Jecel Assumpcao Jr <jecel at merlintec.com>:
> >> > Colin Putney wrote on Wed, 19 Aug 2009 14:25:21 -0700:
> >> >> On 19-Aug-09, at 10:15 AM, Jecel Assumpcao Jr wrote:
> >> >>
> >> >> > For example, I would far prefer to
> >> >> > see Squeak move to a binary based development model (I would
> mention
> >> >> > Projects and Etoys here) than the current source based things we
> are
> >> >> > doing (trunk, bob or whatever).
> >> >>
> >> >> Forgive me for seizing on a throw-away comment like this, but would
> >> >> you mind expanding on this a bit? Are you saying you prefer something
> >> >> spoonish, where CompiledMethods  are passed directly from image to
> >> >> image? Something else?
> >> >
> >> > Heh, I got asked about this on IRC as well. Though I had actually
> >> > started to explain this a little in the original email, I ended up
> >> > deleting it to keep on topic. With a new subject line I don't feel I
> >> > have to worry about that. Some details about this (with a few
> drawings)
> >> > can be found in the Chunky Squeak wiki page:
> >> >
> >> > http://wiki.squeak.org/squeak/584
> >> >
> >> > The idea is to be more like the Etoys users which can load binary
> >> > projects containing not only the code they need but also hand crafted
> >> > objects which have no source (like a drawing, some nested Morphs or
> even
> >> > some text). This is very simplistic compared to Spoon, and my proposal
> >> > was even more simplistic. In particular, this doesn't handle the case
> >> > where any changes to bytecodes or object format are needed.
> >> >
> >>
> >> The central question, which arising immediately is, what is the
> >> credible way(s) to reproduce such artifacts?
> >> When we having a source code, we could (re)compile it on a different
> >> system. But what you propose to do with pure binary data, a soup of
> >> objects, in respect that it is incredibly hard to understand, what
> >> bits you need and what's not, in case if you need to do clean-up ,
> >> refactor, rewrite and simply analyze what is happening.
> >> This is what making a huge difference, for instance, between
> >> applications with open source code and applications shipped in binary
> >> form - you can only report bugs, but can't realy make any suggestions
> >> about what happening.
> >> I don't think that developers of Squeak should be victims of such
> >> situation(s).
> >
> >     it is possible to have your cake and eat it too.  One can create a
> > binary format that includes source and includes the meta-source for its
> > creation.  But including a binary representation allows much faster
> loading,
> > loading without a
> > compiler, and source hiding if one choses not to include the source.
> >
> There are other advantages, such as not cluttering up the changes file when one loads a package  In the VW parcel system, to which I added source management, we replaced the SourceFiles with a SourceFileManager whose job was to manage the sources and changes file and an arbitrary number of source files for parcels, the binary format.  In
> > the parcel file the source pointers of compiled methods are the positions
> of
> > their source in the parcel source file.  When one loads a parcel the
> > SourceFileManager adds the file to its set of managed files and assigns
> an
> > index for the source file.  The parcle loader then swizzles all the
> source
> > pointers so that they include the source file index along with the
> position.
> >  So accessing the source for a method loaded form a parcel accesses that
> > parcel's source file.  We used a floating-point like format for source
> > pointers, where the exponent was the source file index, and the mantissa
> was
> > the position in the file.
> > We didn't create a single file format, having two separate files for
> binary
> > and source, which is probably a mistake.  A format with a short header,
> > followed by source, followed by binary, followed by metasource, would be
> > easier to manage than three separate files.
> > We didn't include any metasource, but we did include pre-read, load and
> > unload actions.  I did a very bad job on version numbering and
> prerequisite
> > selection.
> > That's not the whole story but enough to start answering your question.
>  If
> > there is a well-defined definition of the objects in a package and that
> > definition is included in the package as metasource, then one can
> comprehend
> > the binary package's contents by examining the metasource and can
> reproduce
> > creating the package, provided that the tools are careful to impose
> > ordering, etc.
> > best
> > Eliot
>
> I think you inevitably made wrong decisions, because you went this way
> by allowing an
> arbitrary binary data , held by package.
> In such situations it is much more easier to make a mistakes.
> But sure, one who's making no mistakes is one who doing nothing :)


We didn't disallow representation of arbitrary data but we also didn't
support it.  The only thing the Parcel system supports (as in the tool set,
rather than what one can extend the framework to do in specific
circumstances) is to represent code, which it does very well.

What are these mistakes?  Can you be specific?  I think the parcel system
has been a major success.  VW is now deployed as a system of components, the
base image and a much larger suite of parcels.  Parcels are not tied to a
particular version or implementation and yet are still fast to publish and
load.  What's not to like?


>
> Obviously one of the side of such problem is uniform object memory,
> where each object could
> reference any other object and limited only by a imagination of people.
> There is no layers or any other means which could establish a certain
> barriers (which we calling a modules)
> in smalltalk.
> It means, that once you integrated the parcel into image, and started
> using it, you may have a hard times trying to unload it.
> It is possible to develop an image as an artifact, which contains both
> binary & sources , but such approach
> having a drawbacks, which we, by the way, trying to overcome nowadays.
> Practice shows that such approach is credible only
> for a small group of individuals, but becomes a bottleneck if you
> adopt such scheme for a wider community.
>
> So, i think , that before entering this domain (allowing binary data),
> first we should solve more basic problems of smalltalk & its design -
> modularity, name spaces, layering & etc etc.. Only the we could return
> to original question and solve it.
>
> --
> Best regards,
> Igor Stasenko AKA sig.
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://lists.squeakfoundation.org/pipermail/squeak-dev/attachments/20090824/fd974633/attachment.htm