[Tinyos Core WG] 10.25.2006 Meeting Notes are on the wiki

[Philip Levis]

On Oct 27, 2006, at 12:27 PM, Jan Hauer wrote:

> In the telephone conference we agreed (preliminary) to allow arbiters
> to return SUCCESS to  a client that calls Resource.request() even
> though he already owns the resource. On service level (abstracting
> from the Resource interface), however, we want a second call to
> Read.read() to fail if the first one was successful and readDone() has
> not been signalled.
>
> I was about to change the ADC HIL implementation, but there are some
> bigger changes necessary than I had expected - I have to keep state (a
> bit) for all clients now: when a client calls Read.read I must know
> whether he is the owner or not. But setting, say, an "owner" variable
> to the client ID when I get "his" Resource.granted() is not enough,
> because in between the client might call Read.read a second time. If
> he does, I cannot tell that he has called it successfully before (and
> not released it) unless I keep state for him [when the ReadNow
> interface is involved in conjunction with the Resource interface it
> probably gets more complicated]... I may well have overlooked
> something obvious, maybe someone sees an easy solution - otherwise I
> suggest to change the arbiter semantics rather than introduce the
> changes on the service level. Comments ?

Yes, you have to keep a bit of state.

Phil