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Path: sserve!newshost.anu.edu.au!munnari.oz.au!constellation!osuunx.ucc.okstate.edu!moe.ksu.ksu.edu!vixen.cso.uiuc.edu!sdd.hp.com!caen!hellgate.utah.edu!fcom.cc.utah.edu!u.cc.utah.edu!cs.weber.edu!terry From: terry@cs.weber.edu (A Wizard of Earth C) Newsgroups: comp.os.386bsd.questions Subject: Re: CDROM support Date: 4 Jan 1994 18:44:45 GMT Organization: Weber State University, Ogden, UT Lines: 17 Message-ID: <2gcdet$bkk@u.cc.utah.edu> References: <2g5qaq$ng0@u.cc.utah.edu> <DykkFc3w165w@oasys.pc.my> NNTP-Posting-Host: cs.weber.edu In article <DykkFc3w165w@oasys.pc.my> othman@oasys.pc.my (Othman Ahmad) writes: [ ... ] >Beware though that direct memory read can be faster than any DMA given the >right processor. Only true if you bought the wrong bus or the wrong board. The primary utility of bus-mastering DMA is that the main processer can keep doing whatever it needs to do as long as it does it in cache -- a minor case of parallel processing. A machine that can do two things at once is generally faster than a machine that can only do one thing at a time. Terry Lambert terry@cs.weber.edu --- Any opinions in this posting are my own and not those of my present or previous employers.