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 acheap 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