From owner-freebsd-hackers Fri Mar 6 17:06:18 1998 Return-Path: Received: (from majordom@localhost) by hub.freebsd.org (8.8.8/8.8.8) id RAA23507 for freebsd-hackers-outgoing; Fri, 6 Mar 1998 17:06:18 -0800 (PST) (envelope-from owner-freebsd-hackers@FreeBSD.ORG) Received: from sendero.simon-shapiro.org (sendero-fddi.Simon-Shapiro.ORG [206.190.148.2]) by hub.freebsd.org (8.8.8/8.8.8) with SMTP id RAA23427 for ; Fri, 6 Mar 1998 17:06:09 -0800 (PST) (envelope-from shimon@sendero-fxp0.simon-shapiro.org) Received: (qmail 20804 invoked by uid 1000); 7 Mar 1998 01:14:27 -0000 Message-ID: X-Mailer: XFMail 1.3-alpha-021598 [p0] on FreeBSD X-Priority: 3 (Normal) Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 8bit MIME-Version: 1.0 In-Reply-To: Date: Fri, 06 Mar 1998 17:14:27 -0800 (PST) Reply-To: shimon@simon-shapiro.org Organization: The Simon Shapiro Foundation From: Simon Shapiro To: Bob Bishop Subject: Re: SCSI Bus redundancy... Cc: dmlb@ragnet.demon.co.uk, wilko@yedi.iaf.nl, julian@whistle.com, hackers@FreeBSD.ORG, (marino.ladavac@siemens.at) Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG On 06-Mar-98 Bob Bishop wrote: > At 6:02 pm +0000 6/3/98, Simon Shapiro wrote: >>Wrong again. Diesel generators have a 15-180 seconds switch over time. > > True. It's also not widely realised that they aren't awfully reliable. > They > fail to start one time in N, regardless of how often you start them. N > used > to be about 15 last time I had anything much to do with them. I used to run a military radio station (along with telephony stuff, etc.) Somewhere in the Sinai deserts some time ago. Needless to say, we tended to want to keep electricity flowing regularly into our equipment. As the power company was not disposed to run lines to our part of the desert and the enemy (of that time) tended to cut any lines they could see, we used generators. We actually used diesels (from 5KW up to 200MW), but they were arranged as a non-stop. They charged BIG batteries. The microwave people used AC. We never had our radios out. They did. Our system cost 1/5 of theirs. AC is great for many things, but they tend to disappear within 2ms of disconnect from the power generator. BTW, 48VDC P/S for a PC is about $50.00, where an AC one is $15.00. ---------- Sincerely Yours, Simon Shapiro Shimon@Simon-Shapiro.ORG Voice: 503.799.2313 To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message