Path: utzoo!attcan!uunet!mcsun!ukc!dcl-cs!aber-cs!odin!pcg From: pcg@odin.cs.aber.ac.uk (Piercarlo Grandi) Newsgroups: comp.arch Subject: Re: 64-bit addresses Message-ID: Date: 4 Mar 90 21:33:16 GMT References: <1786@gannet.cl.cam.ac.uk> <1990Mar2.232735.6071@world.std.com> <780@dgis.dtic.dla.mil> Sender: pcg@aber-cs.UUCP Organization: Coleg Prifysgol Cymru Lines: 17 In-reply-to: jkrueger@dgis.dtic.dla.mil's message of 3 Mar 90 18:33:58 GMT In article <780@dgis.dtic.dla.mil> jkrueger@dgis.dtic.dla.mil (Jon) writes: It should also be noted that good DBMSs avoid i/o's at very reasonable (and these days, affordable) costs in computation and memory. The basic tools are query optimizing, access methods, cacheing, intelligent buffering, indices, readahead, data clustering, deferred writes. Let me disagree. Unfortunately almost all databases for which a mainframe is worth having are so immense that their working set is always much larger than real memory available. You still rate DBMS perofmance in IO operations per transaction; main memory is used essentially only as scratchpad. No clever strategy or architecture is going to change this. -- Piercarlo "Peter" Grandi | ARPA: pcg%cs.aber.ac.uk@nsfnet-relay.ac.uk Dept of CS, UCW Aberystwyth | UUCP: ...!mcvax!ukc!aber-cs!pcg Penglais, Aberystwyth SY23 3BZ, UK | INET: pcg@cs.aber.ac.uk