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Newsgroups: comp.os.386bsd.development Path: sserve!newshost.anu.edu.au!munnari.oz.au!news.Hawaii.Edu!ames!elroy.jpl.nasa.gov!decwrl!netcomsv!netcom.com!jmonroy From: jmonroy@netcom.com (Jesus Monroy Jr) Subject: Re: [FreeBSD 1.0R] DMA Problems? Message-ID: <jmonroyCIHJA2.oy@netcom.com> Organization: NETCOM On-line Communication Services (408 241-9760 guest) X-Newsreader: TIN [version 1.2 PL1] References: <CI9EC4.AoB@genesis.nred.ma.us> <jmonroyCIB20s.FF8@netcom.com> <2f8kjq$ft2@u.cc.utah.edu> Date: Thu, 23 Dec 1993 11:15:38 GMT Lines: 27 A Wizard of Earth C (terry@cs.weber.edu) wrote: : In article <jmonroyCIB20s.FF8@netcom.com> jmonroy@netcom.com (Jesus Monroy Jr) writes: : [ ... DMA in FDC driver ... ] : > Previously I had stated that the problem stemmed from the : > possibility that the "RAM refresh" process had priority : > over the "FDC transfer". If this is true then (I beleive) : > there is no way around this problem (except by new hardware). : No. No way. Not a chance. : No to what?.... I mentioned three things... no to what? : The main interaction between memory refresh and DMA is that you can : kill memory off and parity error yourself to death by holding the bus : so long that refreshes get skipped. Dynamic RAM gets pissy when you : skip its refresh. 8-). : my information says that you can skip a few "RAM refresh" cycles... what are you saying? -- Jesus Monroy Jr jmonroy@netcom.com Zebra Research /386BSD/device-drivers /fd /qic /clock /documentation ___________________________________________________________________________