IDENTS - RFC 1434 Identification server.

doc/sysnet/timsrv.info

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+
+Date: 30 AUG 1976 1202-PDT
+From: POSTEL at USC-ISIC
+Subject: Time Of Day Socket Number
+To:   KLH at MIT-AI
+cc:   postel
+
+Ken:
+The number is 37 decimal (45 octal).
+--jon.
+-------
+ 
+RMS@MIT-AI 08/15/76 19:35:47
+To: KLH at MIT-AI
+I forgot to say in the time algorithm
+that a sublist is acceptible only if it contains at least half
+the hosts that responded.  If there is no sublist, all the hosts
+get mailed messages.  The intent if the messages is to get
+people on the hosts to intervene.
+ 
+RMS@MIT-AI 08/15/76 16:48:11
+To: KLH at MIT-AI
+I would like to have the system's time itself set according
+to the other sites' times.  I have worked out an algorithm
+that I think does the right things in all cases:
+1) contact all the sites on the list.
+2) make a list of all the sites that gave answers,
+ and what they gave, including the local host.
+ Contact all of them in parallel to save real time.
+3) sort that list numerically by time returned.
+4) find the longest subsequence which has the property
+that its beginning and end are within 5 minutes.
+"Length" can actually be weighted, with more related hosts
+counting for more.
+5) compute the average time of the hosts in the sublist
+6) Send mail to the appropriate name at all hosts not in
+that sublist, telling them the names of the hosts in the
+sublist and the amount of time they're off from the sublist
+average.
+7) If the local host isn't in the sublist, set its time
+to the sublist average.
+8) this program should be run whenever the system starts up,
+and everything else should wait for its completion.
+Thus, it should be done by TARAKA before anything else.
+
+KLH@MIT-AI 08/15/76 03:32:42
+To: RMS at MIT-AI
+CC: [KSC;TIMSRV INFO] at MIT-AI
+P.S. to message about time server etc.  The following routines
+are fairly modular:
+NETIM - in TIMES >, is a non-interrupt routine that gets the "network time word"
+	given a site # to connect to.
+TIMGTN - in TIMRTS >, is a routine that returns current local time in
+	network-time format.
+TIMCAS/TIMCAD - in TIMRTS >, will convert network-time format into standard
+	DSK-style format.
+
+	Since hacking time stuff is so painful, however straightforward,
+I thought I would point those out, particularly TIMCAS.  The network-time
+format is # seconds since 1/1/1900, GMT - this makes instant
+comparisions easy from any point in network, and is simple enough to
+encode.  It is much more of a win than I thought it would be; TIMES^K
+scans very fast.
+	The algorithm mailer uses is to poll all sites known
+to have Time Servers, and proceed with its local time if it agrees
+with more sites than it disagrees, or if all sites are down.  This
+implies that finding 1 match and 1 mismatch will cause mailer to
+hang up and wait, but 2 matches and 1 mismatch will be taken as confirmation
+of local time.  Criteria for a match is that the absolute difference
+must not be more than 15 minutes, which is extremely liberal I think.
+