Accessing raw devices (was: write alignment matters?)

[Edgar Fuß]

> the code would need to determine the requirements and adapt to the
> particular device it was being used on now
But how would you achieve that?
Given your analogy to accessing terminals, you would need an equivalent of 
termcap.
Or, more reasonably, ioctls telling you the constraints (alignment, max/min 
size, size quantisation etc.) of the device in question.