Uwatec Smart Z data download takes 1.5 hours for only 4 dives

Dazed_75 lthielster at gmail.com
Mon Dec 23 18:21:24 UTC 2013


I have to wonder how much data is being downloaded and the data rate.  I
learned my Aeris XR2 was recording and reporting data for 1 second
intervals.  That can be a lot of data depending on what his computer is
reporting.  Also, according to
http://compnetworking.about.com/od/homenetworking/g/bldef_infrared.htmthere
are 3 different data rates for IR transfer and the slowest is pretty
slow:

*Performance* - Infrared technology used in local networks exists in three
> different forms:
>
>    - IrDA-SIR (slow speed) infrared supporting data rates up to 115 Kbps
>    - IrDA-MIR (medium speed) infrared supporting data rates up to 1.15
>    Mbps
>    - IrDA-FIR (fast speed) infrared supporting data rates up to 4 Mbps
>
> Then too, if there are transmission errors to recover from, it COULD be
pretty slow.  Sorry for top posting, but this did not really fit into the
topic discussion anywhere.


On Mon, Dec 23, 2013 at 6:39 PM, Dirk Hohndel <dirk at hohndel.org> wrote:

>
> On Dec 23, 2013, at 4:29 PM, Linus Torvalds <torvalds at linux-foundation.org>
> wrote:
>
> > On Mon, Dec 23, 2013 at 1:25 PM, Dirk Hohndel <dirk at hohndel.org> wrote:
> >>
> >> Linus - I don't remember why we did not use the fingerprint based
> >> implementation... can you remind me?
> >
> > The fingerprint was too much random crud to actually bother saving
> > without a sane format (it's just a byte blob). We do use it (to
> > generate the dive ID), but we have turned it into something much more
> > easily used for our needs.
> >
> > Also, it's useless for all the cases we had actually seen, so there
> > was very little reason to even worry about it.
> >
> > But I guess we could save it off for specific dive computers, and then
> > in libdivecomputer.c:event_cb(), we cowhen we've calculated the
> > deviceid, we could do something like
> >
> >    /* We don't have this right now, it would walk dives
> >     * starting from the most recent to the oldest */
> >    for_each_dive_reverse(dive, i) {
> >        for_each_dc(dive, dc) {
> >            if (dc->deviceid == devdata->deviceid && dc->fingerprint) {
> >                dc_device_set_fingerprint(device, dc->fingerprint);
> >                return 0;
> >            }
> >        }
> >    }
> >
> > or similar (the above is pseudo-code and the fingerprint isn't a
> > string, it would have to be a blob with length etc).
>
> Yeah, I was thinking of simply converting the fingerprint into hex
> digits and storing those and then put wrappers around that to
> transparently convert from one to the other.
>
> > But this seems to be the first device to actually need it, and the
> > 1.5h download seems to really be due to some independent problem (ie
> > something is much too slow regardless).
>
> I seem to remember that we had a couple of other reports of devices that
> DOWNLOAD all the dives (before showing them to us) unless you tell them
> which dive is the last one that you have. I’m sure Jef will have the data
> on that :-)
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>



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Dazed_75 a.k.a. Larry

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