Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.2 9/5/84; site ssc-vax.UUCP Path: utzoo!watmath!clyde!burl!ulysses!mhuxr!mhuxn!mhuxj!houxm!vax135!cornell!uw-beaver!ssc-vax!eder From: eder@ssc-vax.UUCP (Dani Eder) Newsgroups: net.micro Subject: Re: addresses larger than 32 bits Message-ID: <291@ssc-vax.UUCP> Date: Fri, 21-Dec-84 11:45:30 EST Article-I.D.: ssc-vax.291 Posted: Fri Dec 21 11:45:30 1984 Date-Received: Sat, 22-Dec-84 03:15:14 EST References:<280@oakhill.UUCP> <1258@orca.UUCP> Organization: Boeing Aerospace Co., Seattle, WA Lines: 20 > In discussing addresses larger than 32 bits, remember that those extra > bits pile up additional memory awfully fast. > > To build a computer with 48-bit addresses and to give it 2**48 memory > cells, you would need more cells than there are atoms in the Earth. > Addresses bigger than 48 bits are probably not worthwhile, unless you > need a discontiguous (sparse) address space. > > -- Andrew Klossner (decvax!tektronix!orca!andrew) [UUCP] > (orca!andrew.tektronix@csnet-relay) [ARPA] 2**48 = 281.475 trillion. If you have 8-bit words, and 1 megabit RAM's, you would need 2,147,483,648 of them. Assuming you need one cubic inch per RAM, they would fit in a box 100x100x125 feet. While this is a very large amount of memory, it is a long way from even the number of grains of sand on a large beach, let alone the atoms in the Earth (about 10**50). Dani Eder / Boeing Aerospace Company / ssc-vax!eder / (206)773-4545