On Mar 3, 2004, at 3:16 PM, Andreas Raab wrote:

>> No, I think we should explicitly include instructions in the update
>> stream to pull in specific new versions from SM.  That way you'll
>> always get the right version for the update level you are at, and 
>> it'll
>> always come at the right point in the stream.  If you just always pull
>> in the latest version you're bound to run into trouble (particularly 
>> if
>> you're updating an image that hasn't been updated for a while).
>
> I don't buy this argument. Mostly because there's not much of a 
> difference
> between the updates and packages. Just as food for thought ... what 
> would be
> if we define "image version" in a similar form that we define MC 
> package
> versions? If we did, then we *should* be able to declare an appropriate
> dependency, shouldn't we?

Well, once all the code in the image belongs to some package or other, 
all we'd have to do is create an empty "Image" package that depends on 
all the others. Those dependencies would effectively constitute an 
"image configuration."

For organizing development, the current version of Monticello would 
handle that just fine, except possibly for odd cases where the image 
and the VM interact. I don't know what would happen if MC tried to load 
a package that included a new definition of Behavior, for example.

For distributing updates to users, a similar scheme using SM 
dependencies could be used.

(By the way Göran, I was thinking recently about your plan for 
dependencies in SM. It strikes me that it's essentially a 
constraint-solver - perhaps Cassowary or SOUL could be adapted for the 
purpose?)

> If our current release process isn't able to handle this problem then 
> it
> really feels as if that's something that is fundamentally missing. 
> After
> all, it is one of the primary styles of working so it really should be
> possible to state such a dependency in pretty much the same as we state
> dependencies between packages.

Being the heretic that I am, I think our long-term goal should be to do 
away with the update stream entirely.

Colin