Re: Calendar Manager, callog location ( summary and further ?? )

From: Patrick J Horgan (pjh70@eng.amdahl.com)
Date: Wed Oct 27 1993 - 16:05:23 CDT


In article <PAT.93Oct26140445@crl-sc2.nmsu.edu>, pat@nmsu.edu (Pat Gioannini) writes:
|> My experience with cm ( calendar manager ) indicates that the only
|> way to make cm work with multiple machines where the users move
|> from machine to machine ( as in a student laboratory ) is to make
|> everyone specify their default calendar in .cm.rc . The default
|> calendar should point to the calendar server machine and rpc.cmsd
|> should only run on the calendar server machine.
|>

Or get Alan Humphery's calendar improvement scheme. (agh20@eng.amdahl.com).
It's in testing now, and Alan has permission from Sun (it's based on proprietary
code), to distribute it in the public domain. It let's you have a list of
cmservers in an NIS map, and whenever trying to access a calendar it asks
each cmserver if they own the user's calendar. A nice consequence of this
is that you don't have to know where a user's calendar is to browse it!
Another great thing about it is that it lets you collect callog.xxx's on
file servers where they're easier to back up. Another cool thing is that
it checks for new user's to see which is the "closest" server. Closest
means closest in travel time, not in number of hops. The new user's
calender will live on the nearest cmserver. Using cm stays just the same.
The user doesn't have to do anything to use this, but the system admin has
to install a new daemon on the user's hosts to replace rpc.cmsd, put a
new daemon on each cmserver, and have rpc.cmsd running on each cmserver.
It's been in limited use for about a year. It's great. Alan's releasing
it soon, he has to get permission from Amdahl legal to release it, and
if you want to get on the list to know when it's ready, send him email
at agh20@eng.amdahl.com.

I've seen a couple of other simular replacements, but none of them let's
you use the "for my eyes only" feature. EVERYTHING works normally with
this scheme.
|>
|> The reason for all of this is that the calendar manager communicates
|> with a daemon ( rpc.cmsd ) to get its calendar information. rpc.cmsd
|> does not check to see that the calendar infomation in the callog file
|> has change since that last time it read the file. Therefore if
|> multiple calendars are running and talking to different rpc.cmsd
|> servers, they ignore each other causing loss of information.
|>
|>
|> pat

What can happen is a multiple update -> lost updates problem. Alan's
scheme solves this problem.

Patrick

-- 

These opinions are mine, and not Amdahl's (except by coincidence;).

~~~~~~~~~~~~~~~~~~~~~~~ ~~~~~~~~~~~~~~~~~~~~~~~~~~~ ~~~~~~~~~~~~~~~~~ / | | (\ \ | Patrick J. Horgan | Amdahl Corporation | \\ Have | | pjh70@da.amdahl.com | 1250 East Arques Avenue | \\ _ Sword | | Phone : (408)992-2779 | P.O. Box 3470 M/S 253 | \\/ Will | | FAX : (408)773-0833 | Sunnyvale, CA 94088-3470 | _/\\ Travel | \ | | \) / ~~~~~~~~~~~~~~~~~~~~~~~~ ~~~~~~~~~~~~~~~~~~~~~~~~~~~ ~~~~~~~~~~~~~~~~~~



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