[squeak-dev] Longterm stability of image formats

David T. Lewis lewis at mail.msen.com
Mon Jul 29 11:50:09 UTC 2019

It's a good question, and you are right that we are seeing a lot
of change. 

Right now, I can run a Squeak 1.13 image from 1996 in a 64-bit VM
on my 64-bit Linux laptop and it works quite well. I can also run
an amazing range of old and new images on the SqueakJS VM (see
try.squeak.org). On my same machine, I can also run newer images
on high performance VMs with seemingly unlimited image sizes.

Time will tell if it will be practical to run your 2019 image
20 years from now, but I see no reason to expect that it will not
be possible. And hopefully those older images from 1996 will still be
working too.

It really comes down to whether there will be interested and motivated
people who, 20 years from now, will be happily working to make it happen.
To me, it is an interesting problem, and it gets more interesting as
time goes on.


On Sun, Jul 28, 2019 at 11:43:39PM +0200, Philip Bernhart wrote:
> Hi,
> I just wondered of how stable the current image format is
> supposed to be. When for example I would write now a project
> for say squeak5.2 and then that project gets abandoned for
> some reason but still runs in production, would a squeak VM
> in 10 years still be able to open it?
> As far as I know these changed over the years because
> of:
> 1. Switches from architecture 16 bit -> 32 bit -> 64 bit
> 2. Switches in VM technology: Cog, Spur, Siesta(?), etc.
> Is it even naive to believe to be able to open an old
> image file in the newest VM?
> Thanks for your time,
> Philip

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