Path: utzoo!censor!comspec!lethe!torsqnt!snitor!rmc From: rmc@snitor.UUCP (Russell Crook) Newsgroups: comp.arch Subject: Re: Be Prepared... Message-ID: Date: 15 Feb 91 17:41:22 GMT References: <1991Feb13.160718.25759@visix.com> Sender: usenet@snitor.uucp (nntp news poster) Organization: Siemens Nixdorf Information Systems Ltd. Lines: 51 I tried mailing this to jeff@nsx, but it bounced. Still... > (re: addressing every molecule in your body, and telling grandchildren > about the novelty of an address space extension): > > Now, where's my pedant's hat? Ah, here we go ... :-> > > 64 bits is not enough to address every molecule in your body. > 2**30 is very close to 10**9; hence 2**64 is roughly 2**4 * 10**9 * 10**9 > or 1.6 * 10**19. Since Avogadro's number (number of molecules in one mole) > is a bit more than 6 * 10**23, and one mole of water is 18 grams, then > 2**64 would address about (1.6 * 10**19)/(6 * 10**23) or 2.7 * 10**-5 moles > of water. Since (pant pant pedant pant) the human body is at least half > water (I seem to recall 75%+, but who cares :->), > the address space is insufficient for the alloted task. :-> :-> > > Now, as an exercise for the reader (who, if he/she/it has had any sense > will have given up by this point :->), the following question: > > Assuming the laws of physics won't get in the way (a relatively large > assumption, I must say), and that the current > "4N bytes of memory in three years for the same price as N bytes today" > assumption holds, when will 2**64 bytes be as cheap as 2**20 bytes (i.e., > one megabyte) today? > > Two powers of two every three years, 44 powers to go: 44/2 * 3 = 66 years. > > So, you SHOULD be able to tell this story to your grandchildren... :-> > > Pedant hat off! > Needless to say, I consider my body to be somewhat :-> smaller than the universe as a whole, so 2**64 is certain not to suffice to address the universe. Regards... -- ------------------------------------------------------------------------------ Russell Crook, Siemens Nixdorf Information Systems, Toronto Development Centre 2235 Sheppard Ave. E., Willowdale, Ontario, Canada M2J 5B5 +1 416 496 8510 uunet!{imax,lsuc,mnetor}!nixtdc!rmc, rmc%nixtdc.uucp@{eunet.eu,uunet.uu}.net, rmc.tor@nixdorf.com (in N.A.), rmc.tor@nixpbe.uucp (in Europe) "... technology so advanced, even we don't know what it does." -- ------------------------------------------------------------------------------ Russell Crook, Siemens Nixdorf Information Systems, Toronto Development Centre 2235 Sheppard Ave. E., Willowdale, Ontario, Canada M2J 5B5 +1 416 496 8510 uunet!{imax,lsuc,mnetor}!nixtdc!rmc, rmc%nixtdc.uucp@{eunet.eu,uunet.uu}.net,