Path: utzoo!utgpu!watmath!att!tut.cis.ohio-state.edu!cs.utexas.edu!uunet!wuarchive!texbell!nuchat!steve From: steve@nuchat.UUCP (Steve Nuchia) Newsgroups: news.software.b Subject: Re: NNTP vs Cnews (was: Re: Cnews is not for me) Message-ID: <13705@nuchat.UUCP> Date: 17 Aug 89 13:28:23 GMT References: <2828@ndsuvax.UUCP> <1989Aug12.221624.12153@utstat.uucp> <1894@ucsd.EDU> <1989Aug13.071802.5187@utzoo.uucp> <527@logicon.arpa> <9636@b-tech.ann-arbor.mi.us> <1989Aug16.182527.24840@utzoo.uucp> Reply-To: steve@nuchat.sccsi.com (Steve Nuchia) Organization: Houston Public Access Lines: 38 In article <1989Aug16.182527.24840@utzoo.uucp> henry@utzoo.uucp (Henry Spencer) writes: [re: relaynews as a daemon] >You have to think about when caches get flushed: other things rely on the >disk being fairly up to date, and flushing everything out is a non-trivial >part of the current startup/shutdown overhead. And there are some thorny >locking issues involved. In an nntp environment, which is what I think we should all be planning future development work for, the disk files cease to be so significant. There are good low-overhead ways to implement single-process database software (record management library level), e.g. paper from decwrl for which I don't have a handy citation. >One aspect of it is quite fundamental: there >can only be one relaynews running at a time if file updating is to be This is one very good reason to make it a daemon. It is also desirable to have only one copy to ensure that real users can get a cycle in edgewise. >done properly, and so you need a way to feed that process from multiple >sources -- this is very hard to do portably. Very hard? It is nontrivial only if you want it to be simultaniously portable, low latency, and high throughput. My usual trick is to write for a simple message passing interface and provide implementations for sysV IPC, sockets, and named pipes -- and plain files if necessary. The multiple sources then just need to all use the right library. >Could be done, but it's not quite as simple as it looks. Is anything ever as simple as it looks? If one goes looking for complexity in a system one will find some. I still think a long-running daemon is the way to go. -- Steve Nuchia South Coast Computing Services uunet!nuchat!steve POB 890952 Houston, Texas 77289 (713) 964 2462 Consultation & Systems, Support for PD Software.