All this stuff just seems to be re-inventing the "telcom" protocols used 
on ancient hubbed modem multipoint circuits, 
poll-answer-ack-nak-stationid etc....
D
....
Olin Lathrop wrote:
> 
> More worms.  The big issue you haven't seemed to hit on yet is reliability.
> You should assume that the bus has a small but finite error rate.  
> Checksums
> are good at verifying reliable reception at the receiver, but you can't 
> have
> reliable communication without talking both directions.  That means there
> are ACKs and timeouts.  You have to go thru each possible case of a message
> getting garbled, and messages not getting garbled but the ACKs getting 
> lost,
> etc.
> 
> More worms.

lotsa snippage........
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