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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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 amazing to make picosecond level timing tweaks using an interpreted language to decide when to start & stop pieces of spinning plastic.
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P pixelate@tweesecake.social shared this topic
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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 link to slides? (why not add controllably high-switching nets near the PPL's, or did that not work)? EDIT: saw you posted in thread https://indico.cern.ch/event/1606914/contributions/6771542/attachments/3178052/5652347/2025.11.19_SAMBA_HPTD.pdf
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@jaseg link to slides? (why not add controllably high-switching nets near the PPL's, or did that not work)? EDIT: saw you posted in thread https://indico.cern.ch/event/1606914/contributions/6771542/attachments/3178052/5652347/2025.11.19_SAMBA_HPTD.pdf
@coral here you go: https://chaos.social/@jaseg/116567746676154596
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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)
"We have OCXO at home."
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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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"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
