[Tinyos-devel] TEP116 HIL/HAL discussion

[Philip Levis]

On May 15, 2008, at 8:37 AM, Vlado Handziski wrote:
>
> On the concrete example, CC2420ActiveMesage[CP].nc is the  
> implementation of the active message HIL abstraction fro the cc2420  
> radio. The platform ActiveMessageC.nc is just a name wrapper over  
> this component. There is no portability penalty between the two. So  
> it is a bit wrong to call CC2420ActiveMessage[CP].nc a HAL. For  
> what is worth, we could have opted for a solution where this  
> component is in fact called ActiveMessageC.nc and deal with the  
> selection of the right HIL implementation via shadowing instead of  
> name wrapper and wiring.
>

Well, HIL stands for "Hardware Independent;" CC2420ActiveMessageC is  
not hardware independent. So what is it, if not a HAL? It might be a  
high level of abstraction within the HAL -- which the HAA allows to  
have multiple layers -- but I'd argue that it's within it.  
2420ActiveMessageC, for example, can have CC2420-specific interfaces,  
such as CC2420Packet, which ActiveMessageC cannot.

Phil