[Tinyos-devel] Request for comments on TEP 103, due August 10th

[Philip Levis]

On Jul 26, 2006, at 11:11 AM, David Moss wrote:

>
> As a developer who's using this technology, time is one of my  
> team's most
> valuable resources.  If my team has to spend twice the amount of time
> testing and developing code just to get it to run on two different
> platforms, then that's not worth it.  The fact that David Gay and  
> Johnathan
> are both writing the same end functionality doesn't seem worth it  
> to me
> because their time is equally valuable.  Trying to get people to adopt
> hardware-dependant technology is much more difficult than getting  
> people to
> adopt hardware-independent technology.  If we eventually have 50  
> different
> flash types, who's going to write and test all that code for the basic
> storage implementations?  Not me, and not my team. Time to erase is  
> one
> thing, but time to market is another.  An increase in nitty gritty
> bit-banging performance is usually not worth a delay in getting to  
> a robust
> and finished product.
>
> Having optional platform-dependent and -independent interfaces is  
> probably
> the best route to meet everyone's needs.  If you want your app to work
> everywhere, use the platform-independent interfaces.  If you want  
> your app
> to take full advantage of extra features on a specific chip, then  
> use the
> implementation tailored to that hardware.  Full documentation  
> should be
> provided on how these interfaces work, how to use them, and what to  
> expect.

That sounds right to me. The most important thing is that every chip/ 
platform meets the HIL, which must truly be independent of the  
underlying technology. The HAL is a way to enable developers to  
optimize more if need be. IIRC, none of the TEPs mandate that an  
implementation MUST have a HAL; instead, they mandate the HIL. For  
example, you can meet TEP 103 without having a HAL; it only provides  
some statements on what a HAL SHOULD look like.

(Reading the TEP a bit more carefully, it seems that it lacks the  
MUST statements for the three HILs. David G., Jonathan, I assume this  
is an oversight?)

Phil