Xref: utzoo comp.arch:17655 comp.databases:6797 Path: utzoo!utgpu!news-server.csri.toronto.edu!mailrus!cs.utexas.edu!uwm.edu!rutgers!rochester!pt.cs.cmu.edu!dsl.pitt.edu!pitt!amanue!oglvee!jr From: jr@oglvee.UUCP (Jim Rosenberg) Newsgroups: comp.arch,comp.databases Subject: Re: Extremely Fast Filesystems Keywords: addressing,fractions,floating-point,caches Message-ID: <587@oglvee.UUCP> Date: 10 Aug 90 22:18:43 GMT References: <5539@darkstar.ucsc.edu> <13285@yunexus.YorkU.CA> <30728@super.ORG> <13667@cbmvax.commodore.com> <13578@yunexus.YorkU.CA> Organization: Oglevee Computer Systems, Connellsville, Pa Lines: 26 In rbw00@ccc.amdahl.com ( 213 Richard Wilmot) writes: >I still think it is time to stop trying to use integers for addressing. >They always break down and probably always will. Many computers today have >floating point units. I would like to see floating point used for addressing. Excuse me? You're proposing that addressing be based on *INEXACT* arithmetic?? Sure sounds like a can of worms to me! In scientific programming one has to be careful to test floating point numbers for difference within some epsilon rather than for absolute equality. Not being able to test addresses for exact equality seems like a fatal weakness, IMHO. You could get around this problem by just using the fraction and exponent as "keys" to the address, stripped of their floating point semantic content. But all this does is give you an integer with as many bits as the fraction + the exponent could be. To be assured you could always interpose something between two addressed entities you *need* floating point semantics. And in fact you obviously want them. How are you proposing this would work??? (Alas, this discussion may not belong in comp.databases ...) -- Jim Rosenberg #include --cgh!amanue!oglvee!jr Oglevee Computer Systems / / 151 Oglevee Lane, Connellsville, PA 15425 pitt! ditka! INTERNET: cgh!amanue!oglvee!jr@dsi.com / /