Leaping-clock Sunshines

Mon, 4 Jan 88 11:19:53 EST


I have received several requests for the power-grid graphs mentioned in my
recent message on leaping clocks. They can be found on louie.udel.edu in
~ftp/pub/clock.bit and ~ftp/pub/leap.bit with the usual anonymous login.
Both of these are Sun-format bitmaps suitable for the screenload program
consisting of 41472 octets and must be retrieved in image (binary) mode.
The first graph shows the offset in milliseconds of the eastern power
grid from nominal UT for the day preceeding the 30 June 1985 leap second
and the day one week later. The second shows the offset on 30 June and
1 July. Note that radio reception conditions happened to be so bad during
and after the leap that both the WWVB and WWV clocks had dropped out of
synchronization for three hours following the leap. This further supports
the requirement that the leap should be scheduled in advance not only in
all timekeeping hosts, as is done now in the NTP-speaking world and
fuzzballs, but also in the radio clocks themselves. This in fact should
not be hard to do, since all radio clocks known to me already have a
firmware-driven microprocessor inside.


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