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Xref: sserve comp.unix.bsd.freebsd.misc:2842 comp.periphs.scsi:33981 Path: sserve!newshost.anu.edu.au!harbinger.cc.monash.edu.au!simtel!zombie.ncsc.mil!news.mathworks.com!panix!not-for-mail From: jbrock@panix.com (John Brock) Newsgroups: comp.unix.bsd.freebsd.misc,comp.periphs.scsi Subject: Re: Adaptec 1542C for $125CDN -- comments? Date: 3 Jul 1995 21:36:19 -0400 Organization: Public Access Internet & UNIX Lines: 25 Message-ID: <3ta5uj$614@panix.com> References: <rrwood-2106951636420001@bpci.net3.io.org> <DAy5Et.8uD@watserv1.uwaterloo.ca> <3t01b9$m0i@panix.com> <3t93eo$brd@anshar.shadow.net> NNTP-Posting-Host: panix.com In article <3t93eo$brd@anshar.shadow.net>, Don Whiteside <dwhite@anshar.shadow.net> wrote: >John Brock (jbrock@panix.com) wrote: [...] >: I asked about this a little while ago (prompted by a comment in the >: Linux SCSI HOWTO), and came to the conclusion that this is a phony >: problem. There is a 16MB limit for DMA, but the problem is taken care >: of in the drivers, which is really what you would expect anyway. It >: hardly makes sense that Adaptec or anybody would make a high end SCSI >: card that wouldn't work with a high memory PC. >Phony problem? Well, I guess that depends on how you think of it. If you >mean in the sense that it will still work, sure, it's a phony problem. >If, however, you're one of those unreasonable people like me who thinks >that an expensive card that is supposed to perform at high speed _should_ >perform at high speed, then it _is_ a problem. I was under the impression that the bounce buffers only cost you a few percent in terms of speed, but I could easily be wrong here. Can you give me any idea how much it would reduce the speed of the card if you went from, say, 16MB to 20MB? Would it still be faster than a non-busmastering adapter (and by how much)? -- John Brock jbrock@panix.com