ZEPHYR(1)                                               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 get-
       ting  small quantities of time sensitive information effi-
       ciently from one  client  (or  server)  on  a  network  to
       another.   The object is to accomplish this with the high-
       est 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) HostMan-
       ager 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 respon-
       sible 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  subscrip-
       tions 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)
       Project Athena Technical Plan Section E.4.1, `Zephyr Noti-

ZEPHYR(1)                                               ZEPHYR(1)

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 Insti-
       tute of Technology.  All Rights Reserved.
       Permission to use, copy, modify, and distribute this soft-
       ware 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 pub-
       licity  pertaining to distribution of the software without
       specific, written prior permission.
       M.I.T. DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS  SOFT-
       WARE,  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 TOR-
       TIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE
       OR PERFORMANCE OF THIS SOFTWARE.