[Vm-dev] Re: [squeak-dev] Re: Some notes about SqueakMap dead in trunk images...

[Göran Krampe]

Hi!

Andreas Raab wrote:
> On 3/15/2010 1:26 PM, Göran Krampe wrote:
>> But so far I am unclear as to why this is so. I have now tested LOTS of
>> trunk images backwards and it seems to be broken all the way down to
>> 7179! Funny thing is - my 3.10.1-7175 image works fine.
>>
>> And there may be a hint here: The 7175 image can be opened by an old
>> 3-9-8 VM. But the later 7179 images can NOT be opened due to some kind
>> of image format change.
> 
> Bingo. The issue is that the image format changed for closures and 
> there's been a bug in the image segment loading code that makes the 
> primitive fail in cases where the image format is older, but compatible. 

Ah, good that we know what it is then.

> I've posted a fix for that in VMMaker but I really think SM should stop 
> using image segments for data exchange. Image segments are not a 
> reliable long-term interchange format in an evolving system.

Sure, I am all in agreement. I am slightly amazed we got away with it 
this long :)

When it comes to persistence I am pretty sold on CouchDB these days. If 
you just have the ability to make trivial HTTP GETs and parse JSON - 
then you can load stuff from a CouchDB instance.

Anyway, I really need to sleep but we should take SM by the balls and 
make a plan for how to evolve it into the next 10 years :)

SqueakMap was born somewhere in 2002 IIRC.

> Obviously, this fix requires new VMs.
> 
> Cheers,
>   - Andreas

Mmmm.

regards, Göran