>> The GPU on the
>> Raspberry Pi are closed-source; you need to sign an NDA just to see what
>> registers it has! Nobody is going to be experimenting with that anytime
>> soon.
> The GPU itself is closed source just as the GPU in your PC is.

That is correct. But my PC wasn't designed to be hacked on by hobby 
programmers. It was designed to get real work done.

> Well, the Linux API is open so you do have a way to poke it and also the
> framebuffer is available for bare metal programmers, AKAIK.

I'll bet it's a tad more complex than "if you poke a 1 at this address, 
then this pixel changes colour" though.

> Does your PC have GPIO pins that you can access by simply writing '1' or '0' to
> a file? I thought not. The Pi is the cheapest and easiest way to do physical
> computing.

Yeah, I have no idea what GPIO is, nor what it might be useful for. Does 
it just mean that you can change the logic level of the pin by writing 
some bytes to memory? What are the voltage levels? Presumably you can 
*read* from these pins as well?

It sounds sort-of interesting, but I'm not sure what you could 
realistically use it for. The best I can come up with is putting the Pi 
in a box and connecting the GPIO pins to some buttons so you can control 
the device while it does... whatever the hell it does.



On an unrelated note... I have a small graphing calculator at home. It's 
powered by a Z80, and has a low-res LCD and a bazillion buttons. You can 
"program" it in that you can store small datasets on it, and you can 
make it walk through menu screens in a defined order. Now, if that puppy 
were actually programmable for real... OK, actually nobody else but me 
would care, I guess. :-P

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