Dan Ingalls <Dan at SqueakLand.org> wrote:

> A related topic is general compatibility.  It would be nice if...
> 
> 	A 64-bit VM could read in a 32-bit image
> 	This would mean we wouldn't have to store separate 64-bit images
> 	for every release.
> 
> 	A 64-bit Squeak could read in a 32-bit image segment (ie project)
> 	This would offer at least one-way sharing of projects.
> 
> 	A V4 Squeak could read in a V3 imageSegment
> 	This would carry forward all current projects to V4
Betcha that 9 times out of 10 an image used on a 64bit machine could be
written out as a '32bit' image. Anytime the object space is some
suitable size (let's say 1Gb for now) then the oops could be munged
down and the remaining hard work woud be checking all SmallInts to make
sure they fit into 31 bits. 64bit addresses stored in byte arrays or
whatever would be troublesome perhaps but then if you do that sort of
thing you deserve problems.

It might be easier to do it via a SystemTracer than in the VM though.

tim
--
Tim Rowledge, tim at sumeru.stanford.edu, http://sumeru.stanford.edu/tim
Strange OpCodes: EFB: Emulate Five-volt Battery mode