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.
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)
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
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), zshutdown_notify(8),
Project Athena Technical Plan Section E.4.1, `Zephyr Notification Service'
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
Copyright (c) 1987,1988,1989 by the Massachusetts Institute of Technology. All
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