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Re: [LUG] Free software clock


Gordon Henderson wrote:
> Aparently the big financial bods care - they're talking about sub
> millisecond transactions exactly timed to try to get the edge on share
> trading...

I think they probably need a reality check. All the big stock markets
are pushing or already have sub-millisecond precision in trade
monitoring, the idea I think being you system can spot an opportunity
first it can trade first and make more money. But this kind of depends
on your systems being within 200 miles of the market, which might be
true if you trade in London from within London and the cables are short.

But you get "monitoring data that is 'sub-millisecond'" on global data
feeds -- urm guys if it is global it is already many milliseconds old.
Sure I can see that not adding unneeded delays may be useful, but I fear
that "sub-millisecond" has become a buzz-word or marketing phrase in the
finance world (and I remember when it was just the world of IP routers
that was desperate to go sub-millisecond). Stock trading is a market,
you can only make trades as fast as the second fastest trader at best.

I know there are people who need precise time - the Met Office use to
detect lightening location by essentially listening to static on the
radio from several places and triangulating - for which you want
sub-millisecond accuracy since the triangulation is based on speed of
light which we all know is 1 foot per nanosecond (close enough), so 1000
feet per microsecond, or 1,000,000 feet per millisecond, and a million
feet is a big error, but 1000 feet is generally acceptable for most
purposes to do with lightening. Originally they solved this issue by
buying atomic clocks, I'm guessing they still use them, although GPS
clocks would probably do the trick as well these days.

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