[Tinyos-devel] Request for comments: TEP-108

[Neil Hancock]

Comments on 
http://www.tinyos.net/tinyos-2.x/doc/html/tep108.html  Draft 1.1.2.11

Personally I'm very excited about a comprehensive set of primitives for
resource arbitration.

Practically, TEP108 has a very rich set of interfaces that look pretty
comphrensive. They look well defined, but I haven't given them a lot of
thought as to how I would use them. (my resource limitation). Something like
this would have been very useful in past systems.

I would like to see some of the examples apply to more realistic situations.
The Comms stack is a very good example, where the resource arbitration can
be used instead of unavailable or expensive RAM. It would also be a very
nice way of rate limiting outgoing messages.
Deterministic A/D with tight timing isn't a good example, as I've found a
system needs to be defined around the requirements of the timing and rarely
can be abstracted in software. I would use it at my higher layer data
gathering which owns the A/D and TWI.

The same applies to the UART, as they are typically part of a more specific
subsystem - like the Comms. 

I suspect as defined I would find this layer problematic in a real world
system - say an Atmega128/MSP430 with 80K of code.
 
I don't see a management layer interface, that I find I need when in the
final stages of making software work. To be specific, once the
implementation of TEP108 layer has been unit tested (simulated), and
integration tested and is released, AND then there is a suspect problem with
it, how does a management system (debug?) find out about the internal
states. This is of course not just specific to TEP108, but a must be
considered approach for any software system.

So practically speaking, my expectation would be that I would take a local
copy of it, and add a management interface and instrument the internals.

Good job though in defining an interesting layer for T2.

Neil 






-----Original Message-----
From: Matt Welsh [mailto:mdw at eecs.harvard.edu] 
Sent: Friday, October 20, 2006 3:16 PM
To: TinyOS-Devel list
Subject: [Tinyos-devel] Request for comments: TEP-108

Dear TinyOS developer community:

I have been asked to help shepherd TEP 108 on Resource Arbitration.
This TEP concerns new interfaces in TinyOS 2.x to allow multiple
components to arbitrate access to shared resources, e.g., ADC lines,
UART, radio, etc.

Getting feedback from other TinyOS developers on this document is
essential to moving the TEP process forward. I would appreciate it if I
could get a couple of volunteers to read over this TEP and submit
comments back to me. I will work with the authors of the TEP to revise
the proposal based on your comments.

The current draft for the TEP is attached to this email. Please note
this is a DRAFT only and is not final. 

If you are able to help out, please contact me ASAP!

Thanks for your help,

Matt Welsh

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