Re: Getting physical addresses of mmap'd pages from userspace

[James Chapman <jchapman@katalix.com>]

Tom Cooksey wrote:
> On Tuesday 14 October 2008 17:47:06 Bill Gatliff wrote:
>> Tom Cooksey wrote:
>>
>>> <RANT>
>>> What I don't understand is that I'm trying to do some pretty interesting & cool
>>> stuff with their processors (of course I would say that!), which will probably
>>> help them sell more units. Why then do they make it so difficult to work with
>>> them? It feels like they're shooting themselves in the foot. Madness.
>>> </RANT>
>> Not to perpetuate this further, but I can't resist...  :)
>>
>> That's because their product won't stand on its own; it needs vendor lock-in to
>> be successful.  There really isn't any other explanation for such behavior.
>>
>> Think like a biologist.  If an organism does something, then the upside must be
>> better then the downside of NOT doing that something, or the organism wouldn't
>> waste scarce time and energy doing it--- no matter how ridiculous that something
>> might be.  Unusual markings, mating calls, mullet haircuts...
>>
>> One would think that in the world of high-technology, there would be a huge
>> upside to making products easy to use, which would naturally require free
>> availability of documentation and code (among other things).  But vendors seem
>> to work contrary to that objective, which must mean that there's an even bigger
>> upside to NOT making a product easy to use.
>>
>> Put another way, their revenue stream depends on making your life as painful as
>> possible, so that you won't want to risk repeating that pain by switching to a
>> competitor's product.  It's a "shock collar ^K^K^K electrically-enhanced
>> training aid", so to speak, and we're the dogs.  And not the
>> chihuahua-in-Paris-Hilton's-purse kind of dogs, either.
>>
>> Here's more evidence to support my point: what exactly is the cost to release
>> documentation without an NDA?  About US$0, which is considerably less than the
>> expense of executing an NDA.  So why have the NDA?  Because that expense must be
>> an "investment" in something that nets a larger return to the vendor of the
>> documents in question.  What might that be?  Hmmm....
> 
> I always assumed it's because releasing the source opens them up to patent
> infringement law suits? Some companies are more paranoid than others.

Some companies won't publish open software interface docs for their
devices because they think doing so will give their competitors an
advantage by giving away some info about how their device works
internally. They don't understand open source, period.

It's important to choose hardware devices carefully when developing an
Embedded Linux product; avoid any devices which don't have open source
drivers or docs whenever possible.

All device vendors understand money. If they start to lose market share
because Qt isn't supported by their devices then they might change their
approach. :)


-- 
James Chapman
Katalix Systems Ltd
http://www.katalix.com
Catalysts for your Embedded Linux software development