Path: csiph.com!v102.xanadu-bbs.net!xanadu-bbs.net!feeder.erje.net!eu.feeder.erje.net!eternal-september.org!feeder.eternal-september.org!news.eternal-september.org!.POSTED!not-for-mail From: Eric Sosman Newsgroups: comp.lang.java.programmer Subject: Future of computing [Was: Re: error discription and solution] Date: Thu, 06 Mar 2014 12:03:46 -0500 Organization: A noiseless patient Spider Lines: 46 Message-ID: References: <7ad4a15c-7e35-4d08-a61f-4d673f5d4ef0@googlegroups.com> <081fg9thirl4u17mdbeq8q3oocgtbakr7t@4ax.com> <97SdnYwVB7SC1onOnZ2dnUVZ8gednZ2d@bt.com> <140f3bv3kst7.7zenor3r2v2k.dlg@40tude.net> <5ujw21gfmtzd$.1jtrdvdlsnf4y.dlg@40tude.net> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Injection-Date: Thu, 6 Mar 2014 17:03:45 +0000 (UTC) Injection-Info: mx05.eternal-september.org; posting-host="bd4e1cba8d8592bec5d5ed9e4537fbfd"; logging-data="23338"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX18X1oPckwFk/2++hc5KLqYX" User-Agent: Mozilla/5.0 (Windows NT 5.1; rv:24.0) Gecko/20100101 Thunderbird/24.3.0 In-Reply-To: Cancel-Lock: sha1:8Q1zpLOZp2mdQJBISi6mo5EeKT8= Xref: csiph.com comp.lang.java.programmer:27694 On 3/6/2014 10:25 AM, Chris Uppal wrote: > Eric Sosman wrote: > >> The interesting question, I think, is What Happens Tomorrow? >> Will quantum computers or thought-directed computing or positronic >> brains change things as fundamentally as they have changed since >> Mel? Will the Best Practices we promote today be dismissed as just >> so much primitive bunkum? Naturally, I don't know -- but I wouldn't >> bet against it ... > > Nor I, but also I think the process has already started, in a small way, and > has largely been missed. No, I'm not talking about multi-core processing (or > variants on that theme). The pendulum has swung back, and efficiency /should/ > now be of first-tier interest -- not so much for saving time, but for saving > /energy/. Only desktop machines can ignore their energy use; servers and > "devices" are (in their very different ways) much more sensitive to power > consumption. (Topic drift severe enough to be called "topic lurch"): Hadn't thought of that, specifically, but you may be right about energy expenditure changing the whole face of computing. Years ago I read an article (in Scientific American, maybe?) about thermodynamically efficient computers, in which the authors maintained that such computers would have to be reversible: Apply a positive bias voltage to the components and the computation runs forward, apply a negative bias and it runs backward. (The article presupposed that information-theoretic "entropy" a la Shannon was equivalent to the thermodynamic "entropy" of Carnot et al. I wasn't the least bit sure of the equivalence, but later read a transcript of an address by Richard Feynman in which he seemed to take it as axiomatic. Feynman's Nobel Prize collection is larger than my own, so I'm inclined to take his word for it.) Anyhow, if efficient computation has to be reversible, what can we deduce about an efficient programming language? One immediate consequence: NO ASSIGNMENT OPERATOR, because such an operation wipes out the former contents of the target and is thus not reversible. Start thinking about programming entirely with exchange operators, and today's Best Practices start to look somewhat beside the point ... -- Eric Sosman esosman@comcast-dot-net.invalid