On Thu, Mar 12, 2015 at 7:24 AM, Frank Shearar <frank.shearar at gmail.com>
wrote:

> It's right where we left it. Spur introduces a new object memory
> format, so we're doing the right thing: we're breaking the format and
> telling people.
>
> When you load packages into a Spur image, things will just work. When
> you load changesets, things will just work. As far as I know, we've
> taken care that ImageSegments will also load into Spur, and just work.
>

Ah, not quite.  Image segments saved in 32-bit Spur will load in 32-bit
Spur.  Image segments saved in 64-bit Spur will load in 64-bit Spur.  Image
segments saved in Cog will load in Cog.  But no interoperability is
possible (yet!).  And indeed I believe that image segments saved in the
64-bit Interpreter VM will only load in that 64-bit VM.

The problem with image segments is that they are in the format of the VM's
heap objects.  However, Bert and I want co co-mentor a project to implement
image-level support for loading segments from "foreign" object memories.
Alas GSoC did not approve our organization this year.  Maybe soon.  Or
maybe some student at one of the teaching institutions using Squeak or
Pharo would be interested in having a go.

Note that e.g. Fuel does not have this problem.

But sometimes, if you want to actually make progress, you're going to
> have to bite the bullet and make breaking changes.
>

+1.  Spur has lots of advantages over the existing system but these can't
be introduced without forcing a change to a new image and a new VM.

frank
>
> On 11 March 2015 at 20:45, Trygve Reenskaug <trygver at ifi.uio.no> wrote:
> > What's happened to the "write once, run everywhere" that used to be the
> > hallmark of Smalltalk?
> >
> >
> > On 11.03.2015 21:34, Chris Muller wrote:
> >
> > Hi Eliot and all, for this release I wonder whether we should provide
> > alternate binary's in the bin directory of the VM to help users manage
> > the different image formats.
> >
> > What if, in addition to bin/squeak, Cog would include bin/cog and Spur
> > would include bin/spur.  In that case, although bin/squeak would be
> > whoever was installed last, at least users could be explicit about
> > which VM they want to launch which image.
> >
> > I know we also talked about some universal bin/squeak which could id
> > the image format and launch the appropriate binary, which would be
> > great.
> >
> > We should plan on doing _something_ in this area for the release.
> >
> >
> >
> >
> >
> >
>
>


-- 
best,
Eliot
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