Sorry about the blown hubs. Good news about owserver with multiple buses,
however.
On Tue, Aug 2, 2011 at 9:23 AM, Steinar Midtskogen <[email protected]>wrote:
>
owserver has a -uall option which I assume will make everything
> connected to all the adapters appear as if they were on a single bus.
> Which will simplify the addressing compared to the 1-wire hub approach
> as well. Is this correct? And is it likely that this will work well
> on that many adapters? I suppose few have tried.
>
>
I just tried 7 DS9490R adapters (all I had at hand). Worked well.
>From lsusb:
Bus 001 Device 018: ID 04fa:2490 Dallas Semiconductor DS1490F 2-in-1 Fob,
1-Wire adapter
Bus 001 Device 017: ID 04fa:2490 Dallas Semiconductor DS1490F 2-in-1 Fob,
1-Wire adapter
Bus 001 Device 016: ID 04fa:2490 Dallas Semiconductor DS1490F 2-in-1 Fob,
1-Wire adapter
Bus 001 Device 015: ID 04fa:2490 Dallas Semiconductor DS1490F 2-in-1 Fob,
1-Wire adapter
Bus 001 Device 014: ID 04fa:2490 Dallas Semiconductor DS1490F 2-in-1 Fob,
1-Wire adapter
Bus 001 Device 013: ID 04fa:2490 Dallas Semiconductor DS1490F 2-in-1 Fob,
1-Wire adapter
Bus 001 Device 012: ID 04fa:2490 Dallas Semiconductor DS1490F 2-in-1 Fob,
1-Wire adapter
I believe that the only limit of adapters is libusb and the USB protocol.
owserver puts all the adapters in linked list of effectively unlimited
size.
> Will owserver be able to access sensors on different adapters
> simultaniously, and so be able to handle requests faster than the hub
> solution? I suppose I could also run 16 (or whatever) instances of
> owserver to achieve that speed, but that's not as neat.
>
>
Essentially the buses can operate concurrently.
owserver creates a separate thread for each "request" (i.e. read or write or
directory list).
Each bus is locked (independently) during communication. And each 1-wire
slave is locked (independently) during each request.
There is some global contention for some memory structures, but this should
be very fast compared to 1-wire activity.
To keep independence, owserver needs to know which bus each slave is on. We
find that initially from directory listings, or a direct scan (done in
parallel on all the buses) and then caced for performance.
So yes, owserver should be able to efficiently handle multiple buses.
Splitting up each bus to independent owservers and then aggregating them
would work, but probably doesn't add much.
Paul Alfille
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