From mboxrd@z Thu Jan 1 00:00:00 1970 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on polar.synack.me X-Spam-Level: X-Spam-Status: No, score=-1.9 required=5.0 tests=BAYES_00 autolearn=ham autolearn_force=no version=3.4.4 X-Google-Language: ENGLISH,ASCII-7-bit X-Google-Thread: 103376,c6c96fe0302f04f X-Google-Attributes: gid103376,public X-Google-ArrivalTime: 2002-08-27 11:23:25 PST Path: archiver1.google.com!postnews1.google.com!not-for-mail From: ada@polarhome.com (Anatoly Chernyshev) Newsgroups: comp.lang.ada Subject: Re: POLL: Would you use Ada more if... Date: 27 Aug 2002 11:23:24 -0700 Organization: http://groups.google.com/ Message-ID: <2a038d0e.0208271023.6b0fc44e@posting.google.com> References: <3d5cfe91.17985251@news.demon.co.uk> NNTP-Posting-Host: 147.126.101.90 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8bit X-Trace: posting.google.com 1030472605 6017 127.0.0.1 (27 Aug 2002 18:23:25 GMT) X-Complaints-To: groups-abuse@google.com NNTP-Posting-Date: 27 Aug 2002 18:23:25 GMT Xref: archiver1.google.com comp.lang.ada:28450 Date: 2002-08-27T18:23:25+00:00 List-Id: Dmitry A.Kazakov wrote in message news:... > Robert A Duff wrote: > > > That reminds me of a talk I heard some years ago, given by a guy from > > NASA. He was talking about the software for the Apollo program. They > > had weight budgets for all the pieces of the rocket -- obviously you > > want to make the thing as light as possible if you're launching it into > > space. So the manager asked the software guy how much the software > > would weigh. He said software doesn't weigh anything. The manager said > > come on, these weight budgets are very important, even if it's not much, > > every ounce counts. The software guy tried in vain to convince the > > manager that the weight of software really is zero. Eventually the > > software guy showed the manager a deck of punch cards, and said, See the > > holes? That's the software. Then the manager understood. > > (:-)) > > [OT] I have almost forgot physics, but I suppose that the weights of > RAM/ROM bits set to 0 and 1 should slightly differ. So same CPU may weigh a > pair picogramms (?) more or less depending on the software version. >From the Brillouin's theorem: Increase in information is equal to the decrease in entropy: dI = -dS As soon as dS is in J/(mole*K), the intrinsic energetic part of S depends on the fraction of the matter by which 1 bit is coded, and, of course, on the temperature too. If the bit is coded by, let's say, the spin state of single electron then mole fraction is equal to 1/NA (Avogadro's number = 6.02e23) = 1.66E-24 moles Another example, when the bit is coded by an abacus stone maden of quartz, then molar fraction is going to be mass of the stone (take it for 5g)/molar mass of quartz (60) = 8.00E-02 moles The difference in energy for 0 and 1 states for these devices at 298 K (1*mole*T) will be respectively 4.95E-22 J and 2.38E+01 J. >From E=mc**2 we now obtain the mass difference between 0 and 1 bits for these cases: 5.50E-39 kg and 2.65E-16 kg. If the length of program is 1Mb which is 8388608 bits (we do not consider the domination of 1 states over 0 states because they do not complement each other, since one has to always spent some energy to keep both states ordered) then the mass difference between bulk support (CD, abacus, etc) will be 4.61E-32 kg in the first case or 2.22E-09 kg in the second case (if one was dare enough to code 1Mb program in abacus). This is just an estimation made for fun, so I may be totally wrong. Regards, Anatoly