of books and pads (was Re: community Digest, Vol 179, Issue 23)

Werner Almesberger werner at openmoko.org
Sat Apr 17 19:12:01 CEST 2010

[ Let's use a meaningful subject. ]

Christoph Pulster wrote:
> The format "Pad" is no new idea. The industrial product range use it  
> since many years.

This is, by the way, one sector likely to be able to limit the
complexity of tasks, as I described in my previous post. In
fact, the possibilities and mechanical complexity of a laptop
would just get in the way in many cases.

> I consider the idea, that the future of open source hardware could be
> this: taking high-quality hardware from big players like Apple, which  
> are sexy and free of bugs. But jailbreaking/reflashing the bootloader,  
> installing a free OS.

That's the anti-vendor port approach. FSO had high hopes for it.
A while back, Mickey sounded disappointed with the feasibility of
this. But maybe things have gotten better since ?

I did my share of reverse engineering as well. It's not so bad if
you have plenty of time, the device isn't overly complex, and most
of the functionality is already openly documented.

E.g., for the Psion S5, we had documentation for the SoC, we left
all the hardware bringup to the native operating system, and we
got leaked information for their custom ASIC. We figured out
almost everything we needed to know. Storage (CF) was a bit shaky
but still usable.

Phones are quite a bit more complex. Also, there are areas where
you're currently unlikely to get proper documentation, such as the
modem. So you need to plan around them, e..g, by substituting a
highly integrated solution with a SoC without modem plus a "black
box" modem.

There is little reason for a manufacturer of Closed phones to make
such a choice. So you won't find any mass-market devices that do
this for you.

There are other components where you can choose between Open and
Closed. If Open is not a design objective and you're used to sign
lots of NDAs (or you have blanket NDAs with various chip makers
already), the decision may be fairly arbitrary. Thus each chip
lowers the probability that the overall design will be

That's why I think it's indispensable to be able to choose which
chips you put into your design, and to negotiate with chip makers
before selecting components.

Once you've committed yourself, it's nearly impossible to change
the conditions. (In Openmoko alone, we have two examples: GTA01's
GPS and GTA02's WLAN. In a university project I did some years
ago, there was a competing project from another university. We had
insisted on permission to GPL our driver, while our competitors
accepted an NDA that didn't let them. Ironically, even after we
released our driver they never managed to get that NDA changed.)

- Werner

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