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Path: sserve!newshost.anu.edu.au!harbinger.cc.monash.edu.au!msuinfo!gmi!srvr1.flint.umich.edu!newsxfer.itd.umich.edu!zip.eecs.umich.edu!yeshua.marcam.com!news.mathworks.com!news.alpha.net!uwm.edu!math.ohio-state.edu!hobbes.physics.uiowa.edu!newsrelay.iastate.edu!news.iastate.edu!news.iastate.edu!michaelv From: michaelv@MindBender.HeadCandy.com (Michael L. VanLoon) Newsgroups: comp.unix.bsd Subject: Re: HELP: installing netbsd+64mb RAM+adaptec Date: 11 Nov 1994 20:30:02 GMT Organization: HeadCandy Associates... Sweets for the lobes. Lines: 40 Message-ID: <MICHAELV.94Nov11143004@MindBender.HeadCandy.com> References: <1994Nov11.071053.26169@slate.mines.colorado.edu> <1994Nov11.071527.130451@slate.mines.colorado.edu> <39vogs$78p@dagny.galt.com> NNTP-Posting-Host: mindbender.headcandy.iastate.edu In-reply-to: alex@pc.cc.cmu.edu's message of 11 Nov 1994 12:36:43 GMT In article <39vogs$78p@dagny.galt.com> alex@pc.cc.cmu.edu (alex wetmore) writes: Ade Barkah (mbarkah@slate.mines.colorado.edu) wrote: > I'm trying to install NetBSD 1.0 via floppies to my system. > This machine is a DECpc 486 class machine, 64 megabytes > of memory, with a 1 gigabyte SCSI drive attached an > Adaptec SCSI host adapter (1542 series.) NetBSD doesn't support DMA transfers on the ISA bus on machines with more ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ than 16 megs. You can use a VLB or EISA based SCSI controller (in 32-bit ^^^^^^^^^^^^ mode) and things should work. Just a quick point of clarification. It's the ISA bus itself that can't do DMA past 16MB of RAM. This is a physical limitation of the brain-dead bus, not of NetBSD. EISA, VLB and PCI don't have this limitation. FreeBSD has bounce buffers which solve the problem. You get a slight performance hit, but it will work on your system. FreeBSD-2.0-ALPHA just came out yesterday. What FreeBSD has is a hack to fix the ISA bus behavior. A necessary hack because of the Neanderthal design of the ISA bus. But a hack, regardless. This hack will also make its way into NetBSD post-1.0, but doesn't currently live in NetBSD-1.0. Your options are to buy a better SCSI card that uses PCI, EISA, or VLB (recommended, just for sheer performance and usability reasons, whether you use NetBSD or FreeBSD [or Linux]). Or, to use FreeBSD. I believe FreeBSD-1.1.5 has the bounce-buffer code for ISA DMA. -- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Michael L. VanLoon michaelv@HeadCandy.com michaelv@iastate.edu Free your mind and your machine -- NetBSD free un*x for PC/Mac/Amiga/etc. Working NetBSD ports: 386+PC, Mac, Amiga, HP300, Sun3, Sun4c, PC532 In progress: DEC pmax (MIPS R2k/3k), VAX, Sun4m - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -