[DM] Plea for constructive progress (Was: Re: [QUANTITY] Plea for pragmatism)

[Alberto Micol]

Dear Brian,

>[snip]
>> At this point my feeling is that we are going nowhere.
>> All these discussions about quantities  are too phylosophical for me.
>  
>
>
>	But not for me, and I believe others on this list. Would "silence" be a measure
>	of progress then?!?
>  
>
?

>	I think this is a difference in software design approach between us. It *does* 
>	take a significant amount of time to go through the steps of use-case/requirement/
>	analysis (URA) before getting to "design". However, once done, the design goes 
>	quickly, and, more importantly, does not have as many re-designs over time. etc etc etc
>
>For all these reasons I conclude that starting from a more general, and abstract, 
>	direction  using URA is needed. Otherwise, we all descend rapidly into implementation 
>	arguments on various minutia or just ignore the others needs. In my opinion, and 
>	experience, a formal design process is the only way to make such a project "work".
>

I remind you that I was the one pushing for user requirements, use 
cases, etc.
And that's because I seriously think that it is the only way to define a 
project,
to define what "success" for the project means, and to be able to 
schedule activities
and to measure progress, etc etc etc.

>Requirements should describe what is to be achieved, and not
>> which class is associated with what, or who inherits from who.
>  
>
>
>	No. That is not the CS definition of a requirement and the last part
>	sounds more like what a design diagram does.
>
>  
>
The difference in our approach is that I start from the user requirements
(read: what an astronomer wants from the DM WG), and
from there I will get to the software and architectural requirements,
and not viceversa. The CS requirements come only later in the process.

>Having said that, I DO agree that the observational models are "king", and 
>	will have the most important role as they shape the "component" level as well as 
>	the basic (quantity) level. I don't believe its rocket science that we can't (at the quantity
>	level) anticipate what these models will look like
>

Let's start with that then!

>I thought that it was decided that we start with Observational Data Model,
>> and not with Quantities. That is certainly a much more pragmatic point
>> of view,
>> am I wrong ?
>  
>
>
>	That was not my exact understanding. My understanding was that we
>	could, and would, start from both ends. With the "quantity" end having 
>	the requirement that it "serves" the "observation" end of the model.
>
>	You all in the "observation" camp, please get going, those of us on the 
>	other end need to hear from you.
>

This is fine, but, please, do not try to make a full-fledge Quantity DM 
without having first
collected all the user requirements. Start with something simple, and build
on it on the way.
Keeping a prototype kind of approach is always a good practice
when the User Requirements are not well defined.

Ciao,
Alberto

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