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Path: sserve!newshost.anu.edu.au!harbinger.cc.monash.edu.au!yeshua.marcam.com!MathWorks.Com!news.duke.edu!news-feed-1.peachnet.edu!emory!swrinde!gatech!news.byu.edu!cwis.isu.edu!u.cc.utah.edu!cs.weber.edu!terry From: terry@cs.weber.edu (Terry Lambert) Newsgroups: comp.os.386bsd.misc Subject: Re: FreeBSD system Date: 27 Apr 1994 20:33:27 GMT Organization: Weber State University, Ogden, UT Lines: 52 Message-ID: <2pmi6n$44k@u.cc.utah.edu> References: <1994Apr20.155710.2992@palantir.p.tvt.se> <5O+tb8n.dysonj@delphi.com> <CotA5p.30u@pegasus.com> NNTP-Posting-Host: cs.weber.edu In article <CotA5p.30u@pegasus.com> richard@pegasus.com (Richard Foulk) writes: ]>>: > The BT545S ISA SCSI controller is good too, but EISA is THE way to go!!!! ]>>: ]>>: EISA is dead, PCI is *the* way to go ?! ]> ]>Well, I am going to suggest the more conservative way to go. PCI is still ]>fairly new and I believe that if someone is asking, then they are not ]>necessarily prepared to "experiment". I agree PCI is in our future, but ]>EISA is solid. ] ]There is also VESA local bus, which is less expensive and much more ]widely available that either of the others. And vastly less reliable than either of the others. o Do you have multiple VESA slots? Which one is a master slot? IS there a master slot on your machine? o Without a master slot, you are not guaranteed cache writeback and/or flush on VESA bus-mastering DMA. Almost all modern disk controllers are capable of bus mastering DMA and almost all modern OS's use it. Your machine will crash if it gets the wrong data because bus mastering DMA is done wrong. o Many VESA cards hold the bus for a relatively long time during transfers. With all VESA slots populated, are you sure that the agregate bus-on time won't screw up you DRAM refresh like it does for almost everyone else with populated slots? You could reduce the bus on time for your disk controller (presumably living in a master slot), but then where is your VESA purchased performance? Seriously, the previous poster was not blowing smoke when they said that EISA is more solid. I expect EISA to have 3-6 months of continued dominance, and that in 6-9 months it will die out in favor of PCI. The main problem with PCI is that people like Gateway have rev'ed to the new Saturn chipset, but still have not updated all their motherboards (the 486 motherboards have been rev'ed, but not their P5-60), so they still can't do cache-writeback correctly (the fix for the old Saturn involved hacking the hardware itself). And you've got to be careful to avoid buying old stock of now-working motherboards (ie: old chipset/workaround) or pay a hefty (~50%) performance penalty. So for right now, EISA is the most consistently reliable high performance bus to get. Terry Lambert terry@cs.weber.edu --- Any opinions in this posting are my own and not those of my present or previous employers.