Re: gEDA-user: Parts Manager Working Document

[usenet@xxxxxxxxxx (Florian Teply)]

Edward Hennessy <ehennes@xxxxxxxxxxxxx> wrote:
> Florian,
> 
> Thanks for the feedback.
> 
> On Jan 9, 2010, at 3:30 AM, Florian Teply wrote:
>> a) There seems to be a link between part and document missing. Documents are 
>> completely described, but never referenced.
> 
> I created an ERD and put it in the working document. 
> 
Ah, thanks, that clears things up a bit.

>> b) Symbol: according to the picture, it should contain a SymbolName, but 
>> according to the Text it's supposed to contain a Symbol filename. This seems 
>> to be a slight inconsistency, i myself would maybe include both a filename and 
>> a textual name for display which could also be a tad more verbose. Example:
>> Filename: 7400-1.sym
>> SymbolName: 7400, Quad NAND
>> After a closer look, nearly the same goes for footprints: Graphics call for a 
>> unique name, text calls for a path.
> 
> Thanks for pointing out the inconsistency.  I had blindly just suffixed surrogate
> keys with "ID" and their human readable counterparts with "name."  I'll fix the
> document.
> 
> Should the description be associated with the part, because a 74AS00, 
> 74ALS00, 74LS00 could use the same symbol?
> 
> Or, the parts manager could extract the description attribute from the symbol file
> during import for a generic description and place it in the field you describe.  The 
> description in the 7400-1.sym:
> 
> description=4 NAND gates with 2 inputs
> 
> Or, the parts manager could do both, but on component instantiation, use the 
> description from the part table?
>
I myself am unsure about that as well. Even though all those 74xx00 do
serve the same logic and are represented by the same symbol, their
behaviour is somewhat different due to their internal structure.
Substantially different in terms of timing, output driving capabilities,
and maybe more. It all depends on the verbosity of the description.
One might want to go for a generic description on the 74xx00 level and
an additional description for a, say 74HC00, telling it's High-Speed
CMOS.

>> c) What i'm missing is models. That could very well be grouped with documents, 
>> entries being something like:
>> ModelID
>> Category (Spice, VHDL, VHDL-AMS, Verilog, Verilog-AMS etc.)
>> Description (Textual, more verbose)
>> SourceURL
>> FileLocation (path)
> 
> I'll add support for simulation models, but I'll need to do a bit more research on
> how the database columns map to symbol attributes.
>
Just as it enters my mind: This parts manager is essentially a
hierarchical parts database. I could imagine that some guys would want
to integrate other stuff like inventory, preferred dealers, pricing,
dealer part numbers and such. On the other hand, not everyone might want
to carry all that stuff around.
If i had such a database around, i'd love to be able to search it
according to current needs, grouping transistors by their beta and
current noise for example. But for that, numerical values will have to
be present which in turn have to be entered. This sounds like a task to
be distributed to many guys...
Is there a possibility to keep the database modular?

Anyways, as Kai-Martin already mentioned: what do YOU think is the 
purpose of this parts manager within gEDA??
In order to have a clean layout, i feel it might be wise to step back 
again for the broad picture to reappear.
I'm gonna try and make up a list of properties of components starting
with passive devices. I'll go from very generic properties to more
exotic ones in a way i guess will be okay with most users and put that
list up for discussion.

Greetings,
Florian



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