Re: [SpecGL] D1 Subdividing the spec. (revision)

DM> Levels:
> +---------+
> |         |
> | Level 3 |
> |         |
> +---------+
> |         |
> | Level 2 |
> |         |
> +---------+
> |         |
> | Level 1 |
> |         |
> +---------+

KD>Do you mean that:
                 1st = Level 1
                 2nd = Level 1 + 2
                 3rd = Level 1 + 2 + 3
                 ===> the case of WCAG for example.

Yes, that's what I mean. I'm only proposing that it be a separate
drawing, because modules can have levels and other complications
can arise. Following the precedent of thousands of "software stack"
diagrams over the decades, I put the most fundamental technology
on the bottom.

DM> Modules:
> +----------+----------+----------+
> | Module A | Module B | Module C |
> +----------+----------+----------+------------+
> |      Core Module - required for all         |
> +---------------------------------------------+
> This drawing deliberately shows a notch at the top to indicate that 
> implementing just the core is conformant.

KD>Which is the same that I have done in my drawing in the sense. you can 
>for example in the conformance section that what I have called Module A 
>is the core module and it's fine. Your drawing just above expresses 
>conformance rules, not technology division.

I disagree with that last part. It expresses technology division by
saying, graphically, that you must implement the core because all the
other modules are on top of it. Implementing Module A does not obligate
you to implement Module B because the two are beside each other at the
same level. Thus, the Core is a division that has a different role
because it's mandatory. Any of the Modules A, B, C are allowed to assume
that the Core capabilities will be available to them.

In summary: vertical positioning indicates dependence, horizontal
indicates independence.

In the later examples Karl and I traded about modules and levels
together, we were drawing different relationships. I'll leave that for
the individual WGs to debate, because I would prefer that an optional
module not have levels within itself, but it could happen.
.................David Marston

Received on Thursday, 19 August 2004 15:28:52 UTC