New SqueakMap on the air... and we got problems Houston!

goran at krampe.se goran at krampe.se
Wed Apr 5 08:59:45 UTC 2006


Hi!

Avi Bryant <avi.bryant at gmail.com> wrote:
> 
> On Apr 5, 2006, at 12:52 AM, goran at krampe.se wrote:
> >
> > Yes, I agree - in *general*. But in the case of SM it has been  
> > different
> > because I didn't have the issue of having to be able read *old*
> > ImageSegments into new code. I only have the issue of being able to  
> > read
> > ImageSegments into the same code that produced it, *but* living in
> > different Squeak versions.
> 
> I would say the most important property is being able to read *new*  
> versions of the map into *old* versions of the code.  That way people  
> aren't suddenly forced to upgrade all their images as soon as a new  
> version gets released.  I work with a wide range of Squeak versions  
> and SqueakMap is a common annoyance because of that.
>
> That would also save you from having to worry about new versions of  
> the SM code loading into old versions of Squeak - as long as people  
> can keep using their old version of SM with new maps there shouldn't  
> be too much grumbling.

Eh? Ok, this is how it works:

- SMLoader can be upgraded at leisure (mostly). Sure, it depends on
SMBase but not much so it probably "works":
- SMServer is the web UI for the server. Can evolve independently of
everything else.
- SMBase is the domain model and is used both locally and on the server.
If the server is upgraded it *might* work fine with loading such a map
into an old SMBase, but only if there haven't been any larger changes.

When the client connects and tries to fetch a new map it first asks if
the "protocol version" is ok. This means that if the server has a new
"protocol version" (which I only bump when I feel we have to) then it
will ask to upgrade the local SMBase. Otherwise it will not.

Now... what do you *mean* with "being able to read *new* versions of the
map into *old* versions of the code"?

IMHO that is... not possible. :) Unless we are talking of simple
behavior changes and no structural changes and that those behavioral
changes "aren't important".
 
> Avi

regards, Göran



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