Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Posting-Version: version B 2.10.3 alpha 4/15/85; site ucbvax.ARPA
Path: utzoo!watmath!clyde!burl!ulysses!ucbvax!tcp-ip
From: tcp-ip@ucbvax.ARPA
Newsgroups: fa.tcp-ip
Subject: The night the clocks stopped
Message-ID: <7565@ucbvax.ARPA>
Date: Wed, 29-May-85 05:25:13 EDT
Article-I.D.: ucbvax.7565
Posted: Wed May 29 05:25:13 1985
Date-Received: Thu, 30-May-85 07:25:40 EDT
Sender: daemon@ucbvax.ARPA
Organization: University of California at Berkeley
Lines: 39

From: mills@dcn6.arpa

Folks,

The evening thunderstorms tonight glitched the power at both our primary
NBS radio WWVB clock receiver at Vienna, VA, and secondary NBS radio WWV
clock receiver 25 miles away at University Park, MD, leaving our fuzzballs
unfit to set your watches to. Even the tertiary GOES satellite clock receiver
at Dearborn, MI, was unreachable because of traffic congestion due in part to
braindamaged host BBN-META trying to set its watch every five minutes around
the clock. Unfortunately, the fuzzies revert to j-random time on 1 January
1985 without comfort of at least one reachable radio fix, which apparently
made a lot of hosts nervous. A veritable onslaught was observed here as
several clock watchers stomped on first one fuzzy and then another when this
occured. I bet a lot of files on IBM PCs up at MIT will have strange
timestamps as a result.

WWVB and WWV radio clock receivers get tummyaches in Summer when ambient
static levels are at their highest. After the glitch tonight, both the primary
and secondary clocks wandered for several hours before eventually
synchronizing on their respective transmitters near Boulder, CO. I tried to
lessen the pain by locking the DCNet swamp to an ISI host, only to discover
that host was locking to the DCNet swamp! Meanwhile, the local power grid was
sloshing to-and-fro milliseconds and glitzing the tracking filters used to
synchronize the DCNet hosts themselves in the absence of the normal
quartz-stabilized reference. All this could have been avoided if we had a UPS
at either the primary or secondary site.

While I am sorry for all those braindamaged timestamps, I again would like to
request of all our timetelling friends: please resist the urge to set your
watches from our fuzzballs with TCP. This causes much grief due to limited
connection resources - recently seven different hosts were observed
simultaneously beating on the DCN1 server at the same time! Puhleeze use UDP
instead of TCP. Also, again note DCN1 is the primary source of accurate time -
all the other fuzzlings can provide time only at degraded accuracy. Finally,
will someone please toss a bomb on BBN-META?

Dave
-------