Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.2 9/12/84; site desint.UUCP Path: utzoo!watmath!clyde!bonnie!akgua!sdcsvax!sdcrdcf!trwrb!desint!geoff From: geoff@desint.UUCP (Geoff Kuenning) Newsgroups: net.micro Subject: Re: addresses larger than 32 bits Message-ID: <277@desint.UUCP> Date: Sat, 22-Dec-84 04:15:28 EST Article-I.D.: desint.277 Posted: Sat Dec 22 04:15:28 1984 Date-Received: Mon, 24-Dec-84 02:46:47 EST References:<280@oakhill.UUCP> <1258@orca.UUCP> Organization: his home computer, Manhattan Beach, CA Lines: 20 In article <1258@orca.UUCP> andrew@orca.UUCP (Andrew Klossner) writes: >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. I think you were thinking 10**48, Andy. 2**48 is only 256x10**12. This is an easily achievable number. Terabit memories have been available for over 15 years; you only need 256 of them to use up 48 bits. Another way to think of this is that 2**48 is 2**32 times 2**16. 2**32 is 4 gigabytes, or about 8 Eagles. So you need 65536*8, or 2**16x2**3, or 512K Eagles to hold 2**48 bits. That's probably more than the number of Eagles that will ever be manufactured, but clearly it is a number that will be achievable in the next decade or two. -- Geoff Kuenning ...!ihnp4!trwrb!desint!geoff