Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: utzoo!watmath!clyde!cbatt!ucbvax!sdcsvax!darrell From: darrell@sdcsvax.UUCP Newsgroups: mod.os Subject: Re: Why no "real" distributed systems? Message-ID: <2694@sdcsvax.UCSD.EDU> Date: Tue, 10-Feb-87 04:30:26 EST Article-I.D.: sdcsvax.2694 Posted: Tue Feb 10 04:30:26 1987 Date-Received: Wed, 11-Feb-87 18:48:11 EST Sender: darrell@sdcsvax.UCSD.EDU Organization: NASA Ames Research Center, Moffett Field, Calif. Lines: 96 Approved: mod-os@sdcsvax.uucp Okay, I'll bite. In the early 1970s, when I started hacking across the ARPAnet, the idea of a dataset (I was in an IBM environment, we did not call them files) existing on a machine and you not caring where that DS was a really neat idea. The thought that a running program might migrate for load balancing or fault-tolerant reasons was also there. Ten years later, I find Dick Watson, working first at SRI and now LLNL, still working on these ideas. The problem of distributed computing is not well defined. DL mentions multiprocessors but does not attempt to define a boundary. Another problem is that putting a lot of heterogeneous stuff together is hard. We have a tendency to solve easy problems and leave the hard stuff as "exercises for the reader ;-)." To put together really heterogeneous systems (and I don't mean VAXen and PDP-11s, but Crays, Suns, Britton-Lee boxes, Evans and Sutherland CT6 systems, etc.) is 1) expensive, 2) hard, 3) lacking in pay-off, appreciation, etc. Why work on it when you can make a buck selling PC sofware (sorry, too cynical). Look at Ethernet: has an incredible number of detractors, but every one is using it. Developing a new network system from hardware to protocols will probably be as difficult as developing new operating systems or programming languages. I wonder how long Boggs/Metcalfe's Ethernet will be around? Modification of a joke I wrote for Usenix 1986 Winter: What type of networking technology will be around for the 22th Century? I don't know, but it will be called Ethernet. . . . I would hope things like Proteon would catch on, but Network Systems and Xerox technology are out there. They exist. People want what exists. It's easy to be a success and get support, and this is only the lowest (hardware) level. I'm glad NCP is basically gone, but it shocks me how entrenched DECnet has become. I also wonder about the bureaucratic minds behind DECnet (not in DEC, but like in NASA's communications schemes at a shall remain nameless Center). The idea that some young scientist (future adminstrator)'s concepts about the use of computing are being formed now with FORTRAN, DECnet, and other things sends shivers up my spine. I can see him decreeing something solely because it was in "his experience" not because he studied the issues. James Martin in his infinite wisdom (sic) noted somewhere that there needs to be at least two more layers over the ISO model: I think they were Accounting, and Administration. Real network people gawked. "Real" world people noded "Yes." Oh, back to Dick. He has a neat diagram of the problems: Communications / \ / \ / \ / \ Operating Systems -------- Programming Languages These three communities don't talk to one another. He harps that the OS people are too infatuated with Unix (with relatively poor network support, brewed, too early on too small a machine), the PL people are infatuated with Ada, and the networking people, well, they have not been around as either community. But is communications all there is to distributed systems? I would hope not. But so long as we get bogged down in things like character set mapping, byte and bit order, word size, and instruction set, reliability, we won't see the light at the end of the tunnel. Note: Standards alone, won't help. (as a Standard's person) More experimental work is needed in all areas. Another antecdote: There are two ways to a mistake in building a computer communiations net: The first mistake is to build it such that it looks like a computer: this is SNA. It's when computer people try to build a communications network without really understanding communications. The second mistake is to build it such that it looks like a phone system: this is X.25. It's when phone people try to build a communications network without really understanding computers. Marty Fouts, John Mashey, others, want to add any thing? >From the Rock of Ages Home for Retired Hackers: --eugene miya NASA Ames Research Center eugene@ames-aurora.ARPA "You trust the `reply' command with all those different mailers out there?" "Send mail, avoid follow-ups. If enough, I'll summarize." {hplabs,hao,nike,ihnp4,decwrl,allegra,tektronix,menlo70}!ames!aurora!eugene Ethernet is a trademark of Xerox Corp. DECnet is a trademark of Digital Equip. Corp. Ada is a trademark of the US DOD AJPO. and Star Wars is a trademark of Lucasfilm, Ltd.