Stopping the system fans to heat up the system to shift clock phase by a few femtoseconds is one of the less hinged ideas I’ve seen come out of CERN lol.
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"We have OCXO at home."
@Gyroplast an OCXO will give you much better phase noise than a PLL, but the difficulty is synchronizing them. In these experiments, they have hundreds or thousands of boards synchronized to a common reference clock.
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Stopping the system fans to heat up the system to shift clock phase by a few femtoseconds is one of the less hinged ideas I’ve seen come out of CERN lol.
(AFAIU this was an experiment for a software retrofit to hardware otherwise incapable of such adjustments)
@jaseg something something xkcd emacs spacebar heating
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R relay@relay.infosec.exchange shared this topic
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@coral I think the scenario of this experiment was that they already had a large number of boards deployed that were lacking “proper” hardware capabilities for this kind of fine-grained adjustment and they evaluated retrofitting that capability to these exising boards in software.
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@jaseg @coral See https://indico.belle2.org/event/10782/contributions/74815/attachments/27775/41084/LHCb_Giessen.pdf for some info on how they are used and where they are installed.
and https://indico.cern.ch/event/681247/contributions/2929079/attachments/1639220/2616679/PCIe40_Common_Readout_for_LHCb_and_Alice.pdf for more card specific info
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Stopping the system fans to heat up the system to shift clock phase by a few femtoseconds is one of the less hinged ideas I’ve seen come out of CERN lol.
(AFAIU this was an experiment for a software retrofit to hardware otherwise incapable of such adjustments)
@jaseg Which kind of implementations could this be used for?
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@jaseg Which kind of implementations could this be used for?
@John_Ligher I think if you can avoid it there are better ways to achieve the same result. AFAIU this was meant as a retrofit for boards that lacked the necessary circuitry to do this in a nicer way.
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@John_Ligher I think if you can avoid it there are better ways to achieve the same result. AFAIU this was meant as a retrofit for boards that lacked the necessary circuitry to do this in a nicer way.
@jaseg I see. Thanks for explaining. ^^
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Stopping the system fans to heat up the system to shift clock phase by a few femtoseconds is one of the less hinged ideas I’ve seen come out of CERN lol.
(AFAIU this was an experiment for a software retrofit to hardware otherwise incapable of such adjustments)
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Stopping the system fans to heat up the system to shift clock phase by a few femtoseconds is one of the less hinged ideas I’ve seen come out of CERN lol.
(AFAIU this was an experiment for a software retrofit to hardware otherwise incapable of such adjustments)
@jaseg Wat.
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Stopping the system fans to heat up the system to shift clock phase by a few femtoseconds is one of the less hinged ideas I’ve seen come out of CERN lol.
(AFAIU this was an experiment for a software retrofit to hardware otherwise incapable of such adjustments)
@jaseg that's a slick idea
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Stopping the system fans to heat up the system to shift clock phase by a few femtoseconds is one of the less hinged ideas I’ve seen come out of CERN lol.
(AFAIU this was an experiment for a software retrofit to hardware otherwise incapable of such adjustments)
@jaseg Proper madness from the devs at CERN. I always like it when there is a common goal and someone is like "let me try something ridiculous so it fits our budget." - Vi
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Stopping the system fans to heat up the system to shift clock phase by a few femtoseconds is one of the less hinged ideas I’ve seen come out of CERN lol.
(AFAIU this was an experiment for a software retrofit to hardware otherwise incapable of such adjustments)
@jaseg how very CERN lol
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Stopping the system fans to heat up the system to shift clock phase by a few femtoseconds is one of the less hinged ideas I’ve seen come out of CERN lol.
(AFAIU this was an experiment for a software retrofit to hardware otherwise incapable of such adjustments)
@jaseg i think lady heather is doing fan temperature control for timing stuff for a while.
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Stopping the system fans to heat up the system to shift clock phase by a few femtoseconds is one of the less hinged ideas I’ve seen come out of CERN lol.
(AFAIU this was an experiment for a software retrofit to hardware otherwise incapable of such adjustments)
@jaseg physicists will do anything to gain a few femtoseconds.
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@jaseg how very CERN lol
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Stopping the system fans to heat up the system to shift clock phase by a few femtoseconds is one of the less hinged ideas I’ve seen come out of CERN lol.
(AFAIU this was an experiment for a software retrofit to hardware otherwise incapable of such adjustments)
@jaseg That's actually not to strange of an idea. Some types of tunable lasers are also tuned via temperature.
Also many years ago there was some paper about determining the location of a computer based on the drift of their clock. Essentially the idea was that room temperature changes with the sun and therefore you can find out of it's day or night. Based on that you can find out the location. -
Stopping the system fans to heat up the system to shift clock phase by a few femtoseconds is one of the less hinged ideas I’ve seen come out of CERN lol.
(AFAIU this was an experiment for a software retrofit to hardware otherwise incapable of such adjustments)
@jaseg This is really neat! What's the scale of the x axis?
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@jaseg This is really neat! What's the scale of the x axis?
@davidr about half an hour I think. The original slides are linked down thread.
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Stopping the system fans to heat up the system to shift clock phase by a few femtoseconds is one of the less hinged ideas I’ve seen come out of CERN lol.
(AFAIU this was an experiment for a software retrofit to hardware otherwise incapable of such adjustments)
@jaseg no, this makes sense 🫠 -
Stopping the system fans to heat up the system to shift clock phase by a few femtoseconds is one of the less hinged ideas I’ve seen come out of CERN lol.
(AFAIU this was an experiment for a software retrofit to hardware otherwise incapable of such adjustments)
@jaseg I am impressed.
