Actually, if you pay attention, it probably only takes your bank a few uS to debit your account when you write a check. It takes 5 days to credit it when you receive one.
A perfect example of asymmetric processing :) Didier KO4BB Sent from my BlackBerry Wireless thingy while I do other things... -----Original Message----- From: "Tom Holmes" <[email protected]> Sender: [email protected] Date: Fri, 16 Sep 2011 21:25:46 To: 'Discussion of precise time and frequency measurement'<[email protected]> Reply-To: Discussion of precise time and frequency measurement <[email protected]> Subject: Re: [time-nuts] Google NTP Servers and smearing leap seconds... All this fuss over microseconds being worth billions and it still takes a bank 5 days to find out if the check I wrote is good? Where's a good manure scoop when you need one? Tom Holmes, N8ZM Tipp City, OH EM79 > -----Original Message----- > From: [email protected] [mailto:[email protected]] On > Behalf Of Bob Paddock > Sent: Friday, September 16, 2011 7:50 PM > To: Discussion of precise time and frequency measurement > Subject: Re: [time-nuts] Google NTP Servers and smearing leap seconds... > > On Fri, Sep 16, 2011 at 2:36 PM, Hal Murray <[email protected]> > wrote: > > > > [email protected] said: > >> You can forget Wall St. firms and Banks for starters. > > > >> They need sub-microsecond accurate timing as some instruments (Forex) > are > >> moving to <10 microsecond latency from order entry to order ack. > > > > 10 microsecond latency doesn't say anything about how accurate the time has > > to be. > > > > Does anybody have a good URL on the accuracy requirements of banks and/or > > stock markets? I expect there are both legal and technical issues. I'd like > > to understand them separately > > There are some big names in Banking and Stocks behind the > Advanced Message Queuing Protocol (AMQP): > > http://www.amqp.org/confluence/display/AMQP/About+AMQP > > http://www.oasis-open.org/committees/tc_home.php?wg_abbrev=amqp > > http://amqp.org/resources/financial-services > > Actually Time Nut Grade measurements are not addressed at this level > to my knowledge. > > <p><b>Round Trip</b>: The term round trip refers to the > process of a peer sending a command to its partner and > receiving confirmation that the command is complete. Round > trips are necessary for synchronization of world views, > however, it is not necessary for a client to wait and do > nothing while a round trip occurs or only deal with a single > round trip at a time.</p> > </li> > > <li> > <p><b>Round Trip Time (RTT)</b>: The term RTT refers to the > time taken to complete a round trip. This is described with > the following formula:</p> > <pre> > RTT = 2*latency_network + latency_processing > </pre> > > <p>Note that RTT at the execution layer differs from RTT at > the network layer. At the network layer the processing > latency is zero resulting in an RTT of twice the network > latency. At the execution layer the processing time becomes > significant if, for example, processing the command requires > sending data to disk. This would be the case with durable > messages and the RTT would then include the Broker's disk > latency.</p> > </li> > > > but I won't be surprised if they are thoroughly > > tangled. > > http://www.imatix.com/articles:whats-wrong-with-amqp > > There is also the even more obscure 0MQ: > > http://www.zeromq.org/ > > > > > -- > http://blog.softwaresafety.net/ > http://www.designer-iii.com/ > http://www.wearablesmartsensors.com/ > >_______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
