>> a) The danger that balloon-alikes which aren't in line with the expansion

>Are there any examples of this in practice?

Sadly yes. Keeping a single design strand is important.
As well as keeping a clear idea of the design progression and responding to
comments and requests.
Particularly when it takes a long time to alter a design and debug it.

>I don't see how the actions of others, other than potentially damaging
>the Balloon reputation, could be detrimental to the original project.

If they are working with us then no, but there will be a single point in
time when the design is frozen and a new version produced. If that contains
errors that have been introduced then the whole project could fail
especially when we often only have sufficient money to do a limited number
of spins before producing a viable board to sell.

This could all be helped by better version tagging and visual differencing
in design tools, so if you are looking for extensions to make the current
Open tools more usable in an open hardware environment then this would allow
more open access to design files because changes (both intentioned and
accidental) could be more easily checked.

>If you're looking at the opportunity cost of people who've decided to
>make variants - rather than buying / making a balloon unit.. surely
>there are enough benefits for them to work _with_ you without having to
>throw up additional technical barriers on an otherwise open design?

Firstly this sort of dense BGA design won't attract many variants, you need
£5-10K just to do a spin because some of the parts have to be bought in 100
or 1000 up quantities. Secondly I don't think we are putting technical
barriers in the way, we are simply trying to make sure that when we develop
a design we have a good chance of improving it at each step. Finally we *do*
want people to work with us both at the level of adding to and using the
boards and in developing its future versions.


>What exactly is the extent of Balloon's openness then.. sounds more like
>"free as in beer" than free as in freedom from what you're saying. I can
>copy Balloon designs royalty free, but the original sources are not
>available for people to modify.

Balloon is open because:
a) We publish full schematics as interactive PDF.
b) We will give anyone who asks for them the Gerbers to allow them to set up
production.
c) We publish the VHDL for the glue that holds the system together.
d) The software is fully open even the bootloader.
e) We are happy to discuss how the board works on this group.
f) We will open the design process to anyone that can help.


>Surely making these mistakes is a freedom people might want to be granted?

Agreed.

>I requested to join the design group (as suggested by Wookey) so I could
>have a stab at converting formats of the closed Altium designs. As an
>EDA tool developer (spare time hobby), I'm curious to test our tools
>with more complex designs like Balloon. I was specifically interested in
>a potential migration path from Altium, and Balloon is the only "open"
>design I know of using that tool.

We use Altium because it's relatively cheap and powerful, some of the high
end systems can cost £50k for one seat, even so Altium at about £6K per seat
is not cheap. Anything that allows us to migrate to an Open development
system is of interest. However as Steve indicates it's not capable enough
yet.

>It wasn't that I wanted to open up the schematics (although I don't
>personally see that would be a _bad_ thing).

The schematics are already open, you can design add-ons and you can debug
your Balloon board.
The next stage of openness would be to place the design files in the public
domain and I hope that it is clear that I don't want to do this for good
reasons rather than because I want to "close" the project in some way.
I simply believe that multiple points of development (i.e. multiple instants
of Balloon boards all slightly different) will sap the limited resources and
time of the small number of people who can drive this forward.


>If this all come back to the question of supposed liability to the
>designers against loss or damage from someone making a variant, then
>that makes me very sad. Just because you discourage people making
>variants for laudable reasons, it doesn't mean you have to forbid it.

Well it is something we have to consider, but so do the Open Software people
and with the right legal wording you can deny all fitness for purpose and
offset the liability onto the person that uses it. iEndian is not
necessarily in the same position because we sell the boards and is therefore
under an obligation to sell a working product that at least fits the
advertised description.

>That is fair enough.. but given a spectrum between closed and open..
>there is obviously scope for further flexibility. Those decisions are,
>of course, none of my business.

I have to disagree I think that your opinion is important, iEndian will make
decisions about what to make because it has to, but we can't do that without
discussion and input from the Balloon Community.


>If you need any assistance, or feature improvements, to make gEDA tools
>that open platform, 
I will be very happy when open tools reach the functional level of tools
like Altium, in particular when a really good open source PCB router gets
written.

Once the next revision of the add-on boards are ready I'll release them, if
these can be ported to an Open design tool then that will be a good step
forward.

Kind Regards

David