[Tinyos-Storage WG] RE: today's meeting

[Kevin Klues]

I remember writing some applications that use these interfaces and I always
ended up using both of them in each of my modules (even if all my module did
was exclusively read or write).  The reason for this is that regardless of
whether you are reading or writing, you always need to know the last
position that was written to or read from (especially when accessing flash
as a log).  When you have separate modules for reading and writing you can
think of them as having a producer/consumer relationship on the shared data
flash.  Without knowledge of where things were last read or written on both
sides, unread data can be overwritten and data can be read from areas of the
flash that have not yet been written to.  In summary, I agree with the
notion that the two interfaces should be combined.  I know that some people
don't like having a bunch of unimplemented events in their code though --
they see it as bad interface design.  I sympathize with this view point
somewhat, but I find it much less cumbersome to have to include empty events
than to mess with wiring in a bunch of interfaces that intuitively belong
together.

Kevin

On 5/25/07, David Moss <dmm at rincon.com> wrote:
>
> Looks like nobody can meet today - probably bargaining for a 4-day weekend
> I
> imagine.  That's cool, let's meet some other time.  In the meantime, let's
> continue to discuss stuff over email at everyone's leisure.
>
> I agree with Phil in that if the language of TEP 128 sounds nit-picky
> about
> 103, it needs to be toned down.  One of the comments Phil brought up was
> about why the authors of 103 separated the read/write interfaces.  My take
> on it is this:  the reason why you would write to flash is so you could
> read
> from flash.  Both read and write interfaces are used often inside the same
> module, because you wouldn't write without also reading, and the module
> that
> writes knows what it'll read.  It seems more cumbersome to deal with
> wiring
> up and handling two separate read/write interfaces than a single interface
> that provides everything you need.  Also, if you don't use some event from
> the single read+write interface, then it gets compiled away anyway with
> zero
> impact to your memory footprint.
>
> Thoughts?
>
> -David
>
>
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-- 
~Kevin
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