[Tinyos-devel] Re: [Tinyos Core WG] time sync interfaces

[Vlado Handziski]

On Dec 19, 2007 5:41 PM, John Griessen <john at ecosensory.com> wrote:

> Vlado Handziski wrote:
> above the AM we should strive for platform-independent
> > meaning of the payload. Following this practice, we can stick with a
> single
> > default cross-platform interpretation of the time stamp data (that might
> or
> > might not correspond 1:1 with the selected HIL precision, i.e. it has to
> be
> > better or equal to).
>
> This keeps true to the idea of HIL HAL HPL separation.  You don't choose
> the time precision
> in advance just because it is an obvious programming snag, you make a HIL
> program that
> converts from other precisions to its standard cross platform precision.
> As that cross platform capability gets better with time, you add more to
> the HIL app,
> or create several levels of HIL.
>
> There's no problem having one app that works across several speedy/fancy
> platforms,
> and another that works across those and all the slow and klunky others is
> there?
>
>
The portable application will take a performance hit from using the HIL
abstraction. The amount of the penalty is proportional to the difference
between the HIL service and the HAL on the platform where the portable code
is executed. If this penalty is considered to be too hight, the application
should give up portability and tap to HAL directly.

Vlado
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