Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Posting-Version: version B 2.10.2 9/18/84; site sdcsvax.UUCP
Path: utzoo!watmath!clyde!bonnie!akgua!sdcsvax!madden
From: madden@sdcsvax.UUCP (Jim Madden)
Newsgroups: net.news
Subject: Re: distributed news systems
Message-ID: <503@sdcsvax.UUCP>
Date: Thu, 29-Nov-84 14:41:18 EST
Article-I.D.: sdcsvax.503
Posted: Thu Nov 29 14:41:18 1984
Date-Received: Sat, 1-Dec-84 19:26:30 EST
References: <1914@nsc.UUCP>
Reply-To: madden@sdcsvax.UUCP (Jim madden)
Distribution: net
Organization: EECS Dept. U.C. San Diego
Lines: 31
Summary: 

Please add the address "sdcsvax!distnews" (which will be a local
mailing list on the UCSD campus) to your distributed news system
mailing list.

Parenthetically, I should say that we've found that the IBIS
distributed file mechanisms from Purdue can provide a  cheap way
to share news between 4.2BSD machines across a TCP/IP network.  The
general news database (spool files, active file, etc.) can be kept on a
single 4.2BSD using the straight news (2.10.2) release.  Users on other
machines (suns, vaxen, pyramids) can read news (using either readnews
or rn) by replacing the local spool directory and active files with
cross machine symbolic link (supported by the IBIS package.)  Some gain
in efficiency occurs if you change the names directly in news system .h
files rather than relying on the symbolic links.  I believe that other
user news functions can also be made to work at trivial coding
expense.

At present, the mechanism relys on the user having accounts on both the
reading machine and on the machine with the news directory but a very
simple change to create a specail "news" IBIS can eliminate that
restriction.  There is considerable expense in processing overhead
associated with the mechanism since IBIS works by replacing many IO
related UNIX system calls with replacement routines (in a library
invoked before libc.a) which analyze parameters and perform appropriate
cross net handshaking when necessary.  Since the processing underlying
news reading is largely system calls of this kind the overhead goes
up.  It seems likely that this extra overhead will exist in any cross
system approach that doesn't rely on operating system changes.

				Jim Madden madden@sdcsvax