zephyr - Zephyr Notification Service
Zephyr is a notice transport and delivery system developed at MIT which
runs under 4.3BSD Unix.
A Notice Transport and Delivery system is a method of getting small
quantities of time sensitive information efficiently from one client
(or server) on a network to another. The object is to accomplish this
with the highest possible fan-out (i.e., client to server ratio) while
maintaining both network and server performance. Zephyr is a multi-
cast notice transport and delivery system based upon an authenticated
datagram protocol. Localized Zephyr servers provide routing, queueing
and dispatching services to clients which communicate with them via the
Zephyr Client Library. Two special purpose Zephyr clients, the
WindowGram client and the HostManager client provide user and client
host communication support.
Zephyrd(8) servers run on designated server machines. These servers
maintain a database of subscriptions and locations for every user using
Zephyr. The servers stay in contact with one another, and provide a
reliable backup system (via duplication) in the event of network
Each client machine on the network runs a zhm(8) HostManager client
program which is the link between the Zephyr servers and the users.
User programs send notices to the HostManager, and the HostManager
forwards these notices to the nearest server for action. The
HostManager is responsible for ensuring that the notices reach a
server, and for finding a new one if its server fails to respond.
Each user on the network usually runs a WindowGram client program
automatically upon login. Zwgc(1) displays notices to the user, and
handles user responses. Only notices to which the user has subscribed
will be sent to the WindowGram client.
Subscriptions are handled through the zctl(1) program. This program
allows the user to add or delete subscriptions from Zephyr, to add the
subscriptions to a file, and to perform other miscellaneous functions.
zaway(1), zctl(1), zleave(1), zlocate(1), znol(1), zwgc(1), zwrite(1),
zhm(8), zephyrd(8), zinit(8), zstat(8), zpopnotify(8),
Project Athena Technical Plan Section E.4.1, `Zephyr Notification
Tony Della Fera (MIT-Project Athena, DEC), Mark W. Eichin (MIT-Project
Athena), Robert S. French (MIT-Project Athena), David C. Jedlinsky
(MIT-Project Athena), John T. Kohl (MIT-Project Athena, DEC), William
E. Sommerfeld (MIT-Project Athena).
Copyright (c) 1987,1988,1989 by the Massachusetts Institute of
Technology. All Rights Reserved.
Permission to use, copy, modify, and distribute this software and its
documentation for any purpose and without fee is hereby granted,
provided that the above copyright notice appear in all copies and that
both that copyright notice and this permission notice appear in
supporting documentation, and that the name of the Massachusetts
Institute of Technology not be used in advertising or publicity
pertaining to distribution of the software without specific, written
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