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From: larwe on 30 Dec 2009 10:27
On Dec 30, 10:00 am, Vladimir Vassilevsky <nos...(a)nowhere.com> wrote:
> D Yuniskis wrote:
> > I want to know what is *possible* before even considering various
> > communication media.
>
> Anything is possible. Providing everything is done right, snake networks

I would not have bothered to reply if I had noticed who the OP was.
All his posts seem to follow the general pattern "Let us hypothesize a
universe constructed entirely of cheese. What is the possibility in
such a universe of being eaten by a purple dragon between the hours of
three and four on a Wednesday afternoon?"
From: D Yuniskis on 30 Dec 2009 12:54
Vladimir Vassilevsky wrote:
> D Yuniskis wrote:
>
>> I want to know what is *possible* before even considering various
>> communication media.
>
> Anything is possible. Providing everything is done right, snake networks
> achieve picosecond level of accuracy over 100M Ethernet. However, this
> doesn't work with WiFi because of unpredictable delays.
>
> BTW, I've done project where I synchronized a network with microsecond
> accuracy over voiceband wireless link.

Was the existing network tweeked in any way? I.e., did you
layer an application on top of an existing COTS network
*without* any special constraints placed on it? If not,
what did you have to "retrofit" in terms of equipment
and/or topology? I.e., how painful/expensive was it for
the customer to make this adaptation?

If the network architecture/implementation was designed
intentionally for this application, what penalties/constraints
were imposed? What were their costs (i.e., what was "traded"
for those constraints)?

I've looked at a proprietary wireless approach using a timing
beacon and hardware designed specifically for the application
and should be able to get O(50ns) by calibrating the receivers
in manufacturing and just running things open loop. But, I
haven't look at temperature effects on that accuracy and
atmospheric effects (the wireless approach tends to suggest
deployment over considerably larger areas -- square miles -- and
I don't want to trade one set of problems for yet another :<
"Gee, why can't we use this to replace our XYZ product, too?")

The wired approach silently and implicitly limits expectations
(deploying miles of wire has a significant cost associated with
it :> )
From: Vladimir Vassilevsky on 30 Dec 2009 13:31

Don,

I am consultant. If you have particular project, I can work on it.
Contact is at the web site.

Vladimir Vassilevsky
DSP and Mixed Signal Design Consultant
http://www.abvolt.com



D Yuniskis wrote:

> Vladimir Vassilevsky wrote:
>
>> D Yuniskis wrote:
>>
>>> I want to know what is *possible* before even considering various
>>> communication media.
>>
>>
>> Anything is possible. Providing everything is done right, snake
>> networks achieve picosecond level of accuracy over 100M Ethernet.
>> However, this doesn't work with WiFi because of unpredictable delays.
>>
>> BTW, I've done project where I synchronized a network with microsecond
>> accuracy over voiceband wireless link.
>
>
> Was the existing network tweeked in any way? I.e., did you
> layer an application on top of an existing COTS network
> *without* any special constraints placed on it? If not,
> what did you have to "retrofit" in terms of equipment
> and/or topology? I.e., how painful/expensive was it for
> the customer to make this adaptation?
>
> If the network architecture/implementation was designed
> intentionally for this application, what penalties/constraints
> were imposed? What were their costs (i.e., what was "traded"
> for those constraints)?
>
> I've looked at a proprietary wireless approach using a timing
> beacon and hardware designed specifically for the application
> and should be able to get O(50ns) by calibrating the receivers
> in manufacturing and just running things open loop. But, I
> haven't look at temperature effects on that accuracy and
> atmospheric effects (the wireless approach tends to suggest
> deployment over considerably larger areas -- square miles -- and
> I don't want to trade one set of problems for yet another :<
> "Gee, why can't we use this to replace our XYZ product, too?")
>
> The wired approach silently and implicitly limits expectations
> (deploying miles of wire has a significant cost associated with
> it :> )
From: D Yuniskis on 30 Dec 2009 14:30
Hi Vladimir,

Vladimir Vassilevsky wrote:
>
> I am consultant. If you have particular project, I can work on it.
> Contact is at the web site.

I'll run this by client (after New Year's). Your location (KC)
may be a problem for them (I'm sure you've dealt with that
"issue" in thepast... seems like most consultants have! :< ).
(BTW, is "Stevenson's" still in business? I can't recall if
they were in KC, MO or KC, KS)

I may try some approaches on a personal project just to see how
well they work "at no risk" (cf my "Bottom feeding..." posts
elsewhere in this newsgroup). Timing constraints there aren't
quite as important (since most folks have "tin ears" :> )

Thanks!
--don
From: Dan Henry on 31 Dec 2009 21:17
On Wed, 30 Dec 2009 07:27:23 -0800 (PST), larwe <zwsdotcom(a)gmail.com>
wrote:

>On Dec 30, 10:00�am, Vladimir Vassilevsky <nos...(a)nowhere.com> wrote:
>> D Yuniskis wrote:
>> > I want to know what is *possible* before even considering various
>> > communication media.
>>
>> Anything is possible. Providing everything is done right, snake networks
>
>I would not have bothered to reply if I had noticed who the OP was.
>All his posts seem to follow the general pattern "Let us hypothesize a
>universe constructed entirely of cheese. What is the possibility in
>such a universe of being eaten by a purple dragon between the hours of
>three and four on a Wednesday afternoon?"

I remember enjoying Mr. Yuniskis' posts and the occasional interaction
with him in the mid '90s, probably more on comp.realtime when it had a
pulse. There are few folks I admire (you know who you are) and he's
one of those. I don't remember when, but he went silent. Maybe I
wasn't looking in the right places, but to me, he'd fallen off the
map, or died, or something, based on the sudden silence. It's nice to
see that he's back, if it's really him.

FWIW, I hold Don in high regard now from my perception of him then
(again, the mid '90s). I understand what you're saying, but in my
opinion, he deserves more respect than you are giving him, but your
respect is yours to give and I respect that. Hey, you're a winner
too!

--
Dan Henry
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