

Power grid change may disrupt clocks - mentat
http://old.news.yahoo.com/s/ap/20110624/ap_on_hi_te/us_sci_power_clocks

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ChuckMcM
I don't think they appreciate just how screwy this can make things. A lot of
embedded controllers use zero crossing detectors in their power supplies to
provide the time signal.

Its been such a good thing for so long that I am not sure people really
internalize the assumption they are making. I see this when I put things (like
embedded controllers) on 'pure sine' UPSs (this is where the AC power charges
the battery and the load always runs off the inverter). Since they do _not_
accurately track 60 hz things like my NetApp filer lose and gain time
sporadically (only kept sane by some NTP work which is poorly supported in the
StoreVault series but that is another rant).

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ithkuil
"anything that flashes "12:00" when it loses power "

Not true. That anything could as well be a battery-less quartz driven clock
that doesn't rely on grid frequency but needs power.

