From owner-freebsd-chat Mon Dec 13 21:34:22 1999 Delivered-To: freebsd-chat@freebsd.org Received: from lariat.lariat.org (lariat.lariat.org [206.100.185.2]) by hub.freebsd.org (Postfix) with ESMTP id 6FC43152D3 for ; Mon, 13 Dec 1999 21:34:18 -0800 (PST) (envelope-from brett@lariat.org) Received: from mustang (IDENT:ppp0.lariat.org@lariat.lariat.org [206.100.185.2]) by lariat.lariat.org (8.9.3/8.9.3) with ESMTP id WAA19082; Mon, 13 Dec 1999 22:34:09 -0700 (MST) Message-Id: <4.2.0.58.19991213222107.00c7fc20@localhost> X-Sender: brett@localhost X-Mailer: QUALCOMM Windows Eudora Pro Version 4.2.0.58 Date: Mon, 13 Dec 1999 22:33:42 -0700 To: Olaf Hoyer , chat@FreeBSD.ORG From: Brett Glass Subject: Re: dual 400 -> dual 600 worth it? In-Reply-To: <4.1.19991214051944.00c08e80@mail.rz.fh-wilhelmshaven.de> References: <4.2.0.58.19991213200556.0473c1e0@localhost> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Sender: owner-freebsd-chat@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.org 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