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VM/Image magic numbers (Re: Pharo 6 snap install)

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Ben Coman

VM/Image magic numbers (Re: Pharo 6 snap install)

The "magic decode for image files" seems related and possibly *very* useful....
http://forum.world.st/magic-decode-for-image-files-td4941712.html#a4941837

Now traditionally the VM has been backward compatible with old Images,
but Pharo doesn't necessarily adhere to that and policy IIUC is
release specific VM/Image pairs.
So does Pharo require extra magic numbers to co-ordinate this?
And how would this interact with OpenSmalltalk policy on these magic numbers?

cheers -ben

On Sat, Apr 15, 2017 at 4:20 AM, Stephane Ducasse
<[hidden email]> wrote:

>
> This is what we always have when we release and we freeze it.
> The vm 60 will be compatible with latest pharo 60 image.
>
>
>
> On Fri, Apr 14, 2017 at 12:09 PM, Luke Gorrie <[hidden email]> wrote:
>>
>> On 14 April 2017 at 08:53, Stephane Ducasse <[hidden email]> wrote:
>>>
>>> We always try to have a major release around mid/end of april
>>
>>
>> Once the dust settles, I think it would be wonderful to have this invariant:
>>
>> - The latest Pharo VM source release is compatible with the latest Pharo image.
>>
>> This would make it easy for me to help nix users. My job will be to package the latest source release of the VM, period, and I will know that users can use this to run the latest image. I don't have much scope to screw things up and make people sad e.g. by shipping a bad commit from the master branch.
>>
>> (Of course it makes life harder for you upstream Pharo maintainers. Now updating the VM source release is a blocker for releasing a new image. Could be that this is too constraining in practice, I dunno. I'm just a guy who wants to setup a stable Pharo that I can use to build an application :-))
>>
>>
>

Luke Gorrie

Re: VM/Image magic numbers (Re: Pharo 6 snap install)

On 15 April 2017 at 01:22, Ben Coman <[hidden email]> wrote:

The "magic decode for image files" seems related and possibly *very* useful....
http://forum.world.st/magic-decode-for-image-files-td4941712.html#a4941837

Now traditionally the VM has been backward compatible with old Images,
but Pharo doesn't necessarily adhere to that and policy IIUC is
release specific VM/Image pairs.
So does Pharo require extra magic numbers to co-ordinate this?
And how would this interact with OpenSmalltalk policy on these magic numbers?

I would really like a copy of the script that checks the magic number and starts the right VM. David, could you share yours please?

I started writing

case file -m @share@/magic "$image" in
'Smalltalk image V3 32b*')
vm=@pharo-vm-cog@
;;
'Smalltalk image Spur 32b*')
vm=@pharo-vm-spur@
;;
'Smalltalk image Spur 64b*')
vm=@pharo-vm-spur64@
;;
*)
echo unrecognized image file format
;;
esac

... but would prefer to avoid reinventing the wheel e.g. on how to find the image name in amongst the various options passed to $@.

I would quite like for my package to be able to open the pharo-launcher image and the various images that this downloads. This means supporting pre-spur images. I would ideally like to do that by building a non-spur version of the latest VM, but I am not sure if that is supported for pharo, there is no mvm script for non-spur. The alternative would be to just build an old VM release with cmake.

David T. Lewis

Re: [Vm-dev] VM/Image magic numbers (Re: Pharo 6 snap install)

On Tue, Apr 18, 2017 at 11:11:07PM +0200, Luke Gorrie wrote:

>
> On 15 April 2017 at 01:22, Ben Coman <[hidden email]> wrote:
>
> > The "magic decode for image files" seems related and possibly *very*
> > useful....
> > http://forum.world.st/magic-decode-for-image-files-td4941712.html#a4941837
> >
> > Now traditionally the VM has been backward compatible with old Images,
> > but Pharo doesn't necessarily adhere to that and policy IIUC is
> > release specific VM/Image pairs.
> > So does Pharo require extra magic numbers to co-ordinate this?
> > And how would this interact with OpenSmalltalk policy on these magic
> > numbers?
> >
>
> I would really like a copy of the script that checks the magic number and
> starts the right VM. David, could you share yours please?

Attached.

Dave

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