First computer with real-time clock?

From: Dwight K. Elvey <>
Date: Tue Aug 3 12:06:08 2004

>From: "Paul Koning" <>
>For autonomous timekeeping independent of technology, the state of the
>art was a second per year or so (that's 10^-8, roughly) around the
>early 1900s. First with pendulum clocks (Shortt clock), then around
>the 1940s or so crystal clocks came in that could match this. And not
>too long after that there came the rubidium (10^-10) and cesium
>(10^-14) clocks. Some of that would be found in military gear, I
>think (Rb at least, Cs somewhat less likely). Consider GPS
>satellites, which have either or both built-in.
> paul

 I thought I'd mention that GPS satellites are very precise
but no longer accurate. The world standards like UTC are not
on the same second as used for GPS. I don't recall how
far things have changed but for political and other reasons,
the world time standards have been changing. GPS are still
locked to being relative to particular data and time. Every
one else has had a few leap seconds here and there. There
is a chart someplace on the web that shows how things are.
Received on Tue Aug 03 2004 - 12:06:08 BST

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