Date: Mon, 13 Dec 1999 22:33:42 -0700 From: Brett Glass <brett@lariat.org> To: Olaf Hoyer <Inferno@nightfire.de>, chat@FreeBSD.ORG Subject: Re: dual 400 -> dual 600 worth it? Message-ID: <4.2.0.58.19991213222107.00c7fc20@localhost> In-Reply-To: <4.1.19991214051944.00c08e80@mail.rz.fh-wilhelmshaven.de> References: <Pine.NEB.3.96.991213220754.55242A-100000@shell-2.enteract. com> <4.2.0.58.19991213200556.0473c1e0@localhost>
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At 09:25 PM 12/13/1999 , Olaf Hoyer wrote: >Hi! > >should be shielded cables, or do I miss something about keeping signals clean? Twisted pairs don't provide the same shielding as coax, but they resist noise surprisingly well. (It's a standard exercise in advanced E&M physics classes to show this.) And twists don't lower the impedance as much as a shield, nor do they require baluns. If you buy a long differential SCSI ribbon cable, you'll find that the pairs are twisted within the ribbon. (The twists stop at the places where the connectors are crimped on, then resume.) >AGP IMHO is some el cheapo implementation of some simple electrical >prolonging of a simple interface for fast vid transfer, like the VESA local >bus design in past days. It is, indeed, a somewhat quick and dirty interface. But it's a good one. It does very fast DMA without involving the CPU, which means good concurrency. In some ways, it's even better suited for hard disks than it is for graphics! >Yes, but if someone really needs, say 20 disks/CD-ROMs attached some meters >away from your box, wouldn't it make sense and be cheaper to put them in a >dedicated file server /server box and attach them via a fast network? That's what I'd do. Inside the box, you could use regular IDE for CD-ROMs or fast interfaces for hard disks. ATAPI is cheap; additional interfaces would probably cost about $5 each. Just a few more chips and connectors on a PC board. Outside the box, you'd use FireWire, SCSI, fast Ethernet, or gigabit Ethernet. --Brett To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-chat" in the body of the message
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