Hi Mark,

On 11/05/2011 09:25 AM, Mark Richards wrote:

> Hello Eloy,
>
> A few thoughts.
>
> OWFS already provides data in a single-file-format, such as branch.ALL,
> volt.ALL...
>
> These .ALL registers appear to be grouped by a logical and common
> purpose. If future device support were to be fashioned against what may
> be considered an existing "standard", grouping dissimilar data in a
> single register would be a departure.

Agreed.

>This would mean that an exception
> exists within an otherwise consistent interface. I would caution that
> one exception quickly leads to another and typically does not end well.

Agreed.

> One of the beauties of OWFS is that a structure information is provided
> to give us the layout for each One Wire device and their data format. If
> a single file contains several disparate elements, how will this be
> reflected in the structure?

By using a file name that gives an idea of what one would get by 
accessing that file? For example, "environment" or "environmental_data"?

> I have, many times, chased after problems that did not exist. These
> learning experiences are valuable, but some can be expensive. So
> considering the problem can we assume that it is believed a performance
> issue exists (reading three files rather than one)? It would be helpful
> to know if the difference will be meaningful enough to justify the efforts.

In my particular case I was mostly thinking along the lines of "easier 
to implement on the microcontroller and in less space". Performance-wise 
I am sure there is a tiny advantage of doing an N-byte data transfer 
than N 1-byte transfers, especially since each 1-byte transfer requires 
sending to the device different function commands. As you say, however, 
I am not sure it is worth the departure from what seems to be the 
"standard" so far.

Thanks for the insightful thoughts.

Cheers,

Eloy Paris.-

> On 11/5/2011 07:41, Eloy Paris wrote:
>> Hello developers,
>>
>> I am working on a 1-Wire device that provides multi-sensor data, i.e.
>> temperature, humidity, luminosity. I'd like to be able to have an OWFS
>> file that allows me to do this:
>>
>> $ cat /owfs2/uncached/99.010203040506/environs; echo
>> temp=25.2 RH=48% light=252
>>
>> This would allow for easy parsing of environmental data without having
>> to access different files, i.e. one file for temperature, another for
>> humidity, etc.
>>
>> I am not sure about how to best set up the struct filetype entry to
>> accomplish this. In particular, what should I use for the suglen and
>> format fields?
>>
>> In looking at the possibilities, it seems to me like ft_vascii for the
>> format is something that could work, but then I am not sure about what
>> to use for the suglen field (I guess I could use the largest length that
>> could be produced).
>>
>> Any thoughts on the approach I am considering or if there is a better
>> way to do this?
>>
>> Thanks in advance.
>>
>> Cheers,
>>
>> Eloy Paris.-

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