ZEPHYR(1)       MIT Project Athena (July 1, 1988)       ZEPHYR(1)

     NAME
          zephyr - Zephyr Notification Service

     DESCRIPTION
          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 failures.

          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.

     SEE ALSO
          kerberosintro(1)
          zaway(1), zctl(1), zleave(1), zlocate(1), znol(1), zwgc(1),
          zwrite(1), zmailnotify(1)
          zhm(8), zephyrd(8), zinit(8), zstat(8),  zpopnotify(8),
          zshutdown_notify(8), syslogd(8)

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     ZEPHYR(1)       MIT Project Athena (July 1, 1988)       ZEPHYR(1)

          Project Athena Technical Plan Section E.4.1, `Zephyr
          Notification Service'

     AUTHORS
          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).

     RESTRICTIONS
          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 prior permission.
          M.I.T. DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS
          SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF
          MERCHANTABILITY AND FITNESS, IN NO EVENT SHALL M.I.T. BE
          LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR
          ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
          PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
          OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH
          THE USE OR PERFORMANCE OF THIS SOFTWARE.

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