Re: gEDA-user: Light? Heavy? Reuse...

[Bob Paddock <bob.paddock@xxxxxxxxx>]

> We need a way to import symbols from the library to the *project*,
> not just to the schematic. The schematic may ultimately be shared by
> many projects, with different parts requirements.
>
> 2. Institutions often have preferred parts lists, stockrooms, etc. It
> makes perfect sense for an institution to make a heavy symbol library
> representing its preferred parts.

Everyplace that I've been institutionalized *always* put this information
in the Bill Of Material.  The schematic proper is looked at by the designer,
maybe the person doing PCB layout if not the designer,
a few people in the design review phase, and the technical that has to repair
the broken boards.  Three to five people at most, and not very often.

Also in a project where there is government approvals involved you want
as little detail as possible in the schematic, be generic (MSHA does
not even want to see
values on the schematic.  Need a way to turn that 'layer' of information
off when making one for them).  Also you want absolutely nothing in
your documentation flow, say a part going obsolete where you must change
the BOM, is going to flow back up the process to force a change in the
schematic.
The fewer documents that change, the less problems you have with updating
your project with "Them", and less expense.  Change *anything* in submitted
documents with MSHA and your looking at least $1000 bucks.

The BOM is going to be looked at by maybe the above people, plus
purchasing, warehouse, sales to estimate delivery dates, production
(board stuffing), QC for testing boards (they only look at the schematics
if something fails, and that had better be rare in your process).
BOM is going to be looked at *every time* there is an new order
for this widget by some part of the institution, even if is only an
automated step, with a cursory human glance.

>The schematic may ultimately be shared by
>many projects, with different parts requirements.

The BOM by definition has to contain the correct parts for the variation
of the schematic that you are building, or it is useless.  BOM will
always have the fully
specified part number, or you can't order the parts..  In our work
flows it always contains at least
a generic footprint reference like "0603" plus a reference to a fully specified
footprint document.  Not all "0603" are the same footprint, unfortunately,
but the generic reference at least gives you some concept of size.

In the past databases have come up as a solution to 'heavy', and that
makes sense
from the technical aspects, but it can't be something like a MySQL server.  The
inmates that are running IT in these institutions balk at installing
anything with the
word "server" in the name (I was told I was competing with them when I did it,
my system was fast and easy to use and theirs was not),
and they sure are not going to let you contaminate "their" database
system with footprint data
or its ilk.  Usually the version control system is pressed into
service because IT almost grasps why it is needed.

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