Path: utzoo!mnetor!tmsoft!torsqnt!news-server.csri.toronto.edu!cs.utexas.edu!sdd.hp.com!spool.mu.edu!news.cs.indiana.edu!news.nd.edu!mentor.cc.purdue.edu!pop.stat.purdue.edu!hrubin From: hrubin@pop.stat.purdue.edu (Herman Rubin) Newsgroups: comp.arch Subject: Re: Be Prepared... Message-ID: <6095@mentor.cc.purdue.edu> Date: 17 Feb 91 18:08:24 GMT References: <1991Feb13.160718.25759@visix.com> <3206@crdos1.crd.ge.COM> Sender: news@mentor.cc.purdue.edu Lines: 28 In article , mccalpin@perelandra.cms.udel.edu (John D. McCalpin) writes: > In article <3206@crdos1.crd.ge.COM>, davidsen@crdos1.crd.ge.COM writes > about a program which fills a 64-bit address space: > > > Assuming that you have a 1 gigaBYTE bus on that memory, it will take > > 316 years (almost 317) to swap a program in. > > On 16 Feb 91 14:25:46 GMT, hrubin@pop.stat.purdue.edu (Herman Rubin) replied: > > Herman> [...] I see no way to get your pessimistic result. > > Herman probably did not understand what Davidsen was saying. > I get a slightly different number from the following calculation: I agree that I did not understand what Davidsen was saying. Now I do, and I wonder why he was saying it. Is he saying that the full address space must be fillable by the technology of today or the near future? Having seen the development of computers, a problem has arisen every time the number of address bits made possible by architectural advances has exceeded the space provided for in the current architecture. Various kludges have to be adopted. We are now reaching the stage where 32 bits for address are not enough. For good reasons, having word size a power of 2 has come in. So we go to 64 bits for address space, and maybe we can go a few decades without changing it. -- Herman Rubin, Dept. of Statistics, Purdue Univ., West Lafayette IN47907-1399 Phone: (317)494-6054 hrubin@l.cc.purdue.edu (Internet, bitnet) {purdue,pur-ee}!l.cc!hrubin(UUCP)