From owner-freebsd-hardware Fri Aug 11 12:58:15 2000 Delivered-To: freebsd-hardware@freebsd.org Received: from alpha.shianet.org (alpha.shianet.org [216.40.132.245]) by hub.freebsd.org (Postfix) with ESMTP id 159F237B7FA for ; Fri, 11 Aug 2000 12:57:58 -0700 (PDT) (envelope-from wrath@shianet.org) Received: from wrath01 (port45.owosso04.tir.com [216.40.133.46]) by alpha.shianet.org (8.9.1/8.9.1) with SMTP id PAA11118 for ; Fri, 11 Aug 2000 15:57:22 -0400 (EDT) Message-ID: <011a01c003ce$6d48ae80$c8026b83@wrath01> From: "Brian" To: References: <00d301c003b9$2d425990$b8209fc0@marlowe> Subject: Re: Best behaved drives for FreeBSD? Date: Fri, 11 Aug 2000 15:57:46 -0400 MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 5.00.2919.6600 X-MimeOLE: Produced By Microsoft MimeOLE V5.00.2919.6600 Sender: owner-freebsd-hardware@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.org All of them run to ground through your board, to the power supply, out the cable, into the receptacle, down the line, through the breaker panel, and down to a ten foot ground rod in the ground. Of course there's dozens of ways of grounding, but more than likely it goes to a ground rod or to the STREET side of your water pipe from the city. It won't do you much good if you're one of those people that cut off the grounding terminal on your power supply cord to fit your pre-1970's receptacle. If you sat there with your ohmmeter you'd probably find that all those wires (40 of them) go to one of the many ground wires on the cable. It's a great idea to use ground shielding to _help_ eliminate crosstalk, but whoever decided to use 24 gauge (I've even seen 30 gauge) wire with even thinner PVC coating (to keep the already giant ribbon from growing to fill your 1U case) should be hung from their toes. until they get a hillbilly electrician on the standards committee, it's going to get worse. next thing you'll know they'll start using solid aluminum wire. Brian St.John brian@wrath.com "the only eighteen year old nerd that doesn't run eunicks at home" ----- Original Message ----- From: "Shawn Barnhart" To: "FreeBSD Hardware List" Sent: Friday, August 11, 2000 1:25 PM Subject: Re: Best behaved drives for FreeBSD? > Can someone explain to me the technical advantages of tying all the > ground lines together at the cable connectors ("40 pin compatibility") > but breaking them off seperately for the rest of the cable ("80 wire > cable")? > > It strikes me that if you're doing ground isolation to keep noise at bay > that tying the grounds together anywhere along the cable run would > defeat the purpose. > > To me this makes no sense, but I'm not an eletrical engineer, either. > > > > > To Unsubscribe: send mail to majordomo@FreeBSD.org > with "unsubscribe freebsd-hardware" in the body of the message > To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hardware" in the body of the message