From owner-freebsd-hackers Tue Jan 30 3:12:29 2001 Delivered-To: freebsd-hackers@freebsd.org Received: from critter.freebsd.dk (flutter.freebsd.dk [212.242.40.147]) by hub.freebsd.org (Postfix) with ESMTP id ECCD437B4EC for ; Tue, 30 Jan 2001 03:12:00 -0800 (PST) Received: from critter (localhost [127.0.0.1]) by critter.freebsd.dk (8.11.1/8.11.1) with ESMTP id f0UBAPK30259; Tue, 30 Jan 2001 12:11:40 +0100 (CET) (envelope-from phk@critter.freebsd.dk) To: thomas@hentschel.net Cc: Peter Wemm , Mark Huizer , freebsd-hackers@FreeBSD.ORG Subject: Re: Clustering FreeBSD In-Reply-To: Your message of "Tue, 30 Jan 2001 03:03:40 PST." <200101301103.f0UB3f144218@falcon.home.hentschel.net> Date: Tue, 30 Jan 2001 12:10:25 +0100 Message-ID: <30257.980853025@critter> From: Poul-Henning Kamp Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG In message <200101301103.f0UB3f144218@falcon.home.hentschel.net>, thomas@hentschel.net writes: >>> What am I doing wrong? Given a diameter of appr. 7cm, I'd come at appr >>> 0.7Mach. Does that mean that within a few years my machine will go >>> KABOOM when booting? >> >> I have a 15K rpm drive if you want to do a recalculation. I think that >> is 1.05Mach, depending on whether you rounded or not. ;-) > >Hang on, there's a bug here somewhere: > >7cm = .07m, >.07m x 3.14... = .22m (per rotation) >.22m *15000/60 = 55m/s or ~ 195km/h or 123 mph, not even close to a fast car. > >We should expect breaking the sound barrier with >75krpm drives >(depending on your altitude and air pressure) That is overlooking that the air rotates in mostly laminar fashion with the platters, isn't it ? -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 phk@FreeBSD.ORG | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message