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Xref: sserve comp.windows.x.i386unix:1560 comp.os.386bsd.questions:2448 Path: sserve!newshost.anu.edu.au!munnari.oz.au!news.Hawaii.Edu!ames!elroy.jpl.nasa.gov!usc!howland.reston.ans.net!zaphod.mps.ohio-state.edu!caen!hellgate.utah.edu!cc.usu.edu!ivie From: ivie@cc.usu.edu Newsgroups: comp.windows.x.i386unix,comp.os.386bsd.questions Subject: Re: XFree1-2 + 386BSD performance Message-ID: <1993May12.211743.67745@cc.usu.edu> Date: 12 May 93 21:17:43 MDT References: <1993May12.025731.29769@latcs1.lat.oz.au> <1993May12.144311.14744@sifon.cc.mcgill.ca> <1993May12.182849.29379@cm.cf.ac.uk> Organization: Utah State University Lines: 18 In article <1993May12.182849.29379@cm.cf.ac.uk>, paul@isl.cf.ac.uk (Paul) writes: > When doing compiles that access disk a lot my system hangs until the > disk activity stops. I think what's happening is that disk interrupts are > crowding out everything else. Is there some way of preventing this, it > would make it a lot easier to run background compiles. At the moment > it's like running a single tasking system because when the disk is being > accessed nothing else happens. > > Incidentally, my drive is an IDE, I get the feeling that this doesn't > happen with SCSI which is why not everyone sees it. Welcome to the wonderful world of IDE! That's right, IDE _doesn't_ do DMA; the CPU has to block-transfer the data to and from the data register. Why? Because on the stock 6 MHz AT, the block output instruction is significantly faster than 16-bit DMA (the DMA controller runs at _3_ MHz, you see). Roger Ivie ivie@cc.usu.edu