From owner-freebsd-questions@FreeBSD.ORG Thu Oct 21 17:27:46 2010 Return-Path: Delivered-To: freebsd-questions@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 639C510656EC for ; Thu, 21 Oct 2010 17:27:45 +0000 (UTC) (envelope-from henry.olyer@gmail.com) Received: from mail-gy0-f182.google.com (mail-gy0-f182.google.com [209.85.160.182]) by mx1.freebsd.org (Postfix) with ESMTP id 12D178FC13 for ; Thu, 21 Oct 2010 17:27:44 +0000 (UTC) Received: by gya6 with SMTP id 6so50127gya.13 for ; Thu, 21 Oct 2010 10:27:44 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:mime-version:received:received:in-reply-to :references:date:message-id:subject:from:to:cc:content-type; bh=JVwkWTQy1OIy9G5j5wwGN1FH0RaAAAhWJ69Oa97LaKM=; b=vvBld3+LExIjxmEZjQHoS17GROMQ9SGUhGB/2Vd1IfGIJqDPA5UoRCutNhJmDn3g1i m6lnvBwVVExk9ar0XI6rwpuzU3sbvecSt2JePwXtqAcp1vKfF1vP+tkzCZSbwJu4L/+0 HNAgoAuV0h29kwwk4DwxAzc9QTT2CXjXZorWw= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type; b=T7Yx4/OXmMxsC1Wtj5u/q6IeXIo5Qcs9KxADxTO+/jgjTsr1YZ1mExlTkcVi6fIqc1 XIAZWcTGuEQcIp7kXeAH/qIeHkSYoCO5C3qiiVjBQpcm3GMzOHE2DaVOxh1dIsGylCfE QPJ85IDYbM0uEzJEU83d8C2iKFugiAyTHz0qk= MIME-Version: 1.0 Received: by 10.42.30.14 with SMTP id t14mr938032icc.311.1287682064037; Thu, 21 Oct 2010 10:27:44 -0700 (PDT) Received: by 10.229.249.195 with HTTP; Thu, 21 Oct 2010 10:27:43 -0700 (PDT) In-Reply-To: <20101021155724.0eb1c5a1@gumby.homeunix.com> References: <20101017143901.GA71132@current.Sisis.de> <20101019074615.GA2183@current.Sisis.de> <20101020022946.GA23035@thought.org> <20101020052601.GA1977@current.Sisis.de> <4cbe9e9a.3qT7q8JUqJxSD8/V%perryh@pluto.rain.com> <20101020165526.GA25310@thought.org> <4CBF21EB.1080003@tundraware.com> <20101020194605.GA78565@stainmore> <4CBF4CB4.6070902@qeng-ho.org> <20101021133844.235fdc72@gumby.homeunix.com> <4CC040E7.7090404@qeng-ho.org> <20101021155724.0eb1c5a1@gumby.homeunix.com> Date: Thu, 21 Oct 2010 13:27:43 -0400 Message-ID: From: Henry Olyer To: RW Content-Type: text/plain; charset=ISO-8859-1 X-Content-Filtered-By: Mailman/MimeDel 2.1.5 Cc: freebsd-questions@freebsd.org Subject: Re: Greybeards (Re: Netbooks & BSD) X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 21 Oct 2010 17:27:46 -0000 My first machine was an IBM 1620, but hey, at least we had an actual disk. A couple of 2311's. To quote a fellow I used to consult for, two days' I had solved a particularly nasty programming problem for his company, "But what have you done for us lately?" On Thu, Oct 21, 2010 at 10:57 AM, RW wrote: > On Thu, 21 Oct 2010 14:32:23 +0100 > Arthur Chance wrote: > > > On 10/21/10 13:38, RW wrote: > > > On Wed, 20 Oct 2010 21:10:28 +0100 > > > Arthur Chance wrote: > > > > > > > > >> 50s) had the experience of programming microcode on a machine by > > >> inserting brass slugs for 0s and ferrite slugs for 1s on a pin > > >> board. > > > > > > I wonder why it was brass/ferrite rather than brass/empty or > > > ferrite/empty. > > > > Dredging up physics unused for 30+ years, ferrite is ferromagnetic > > and intensifies magnetic fields so a coil of wire with ferrite inside > > is a massively bigger inductor then an empty coil. I vaguely remember > > that brass is slightly diamagnetic, but could be mistaken. If it is, > > then it would have the opposite effect and reduce the inductance, so > > you'd get a better difference in signal between brass/ferrite than > > air/ferrite. > > Possibly. I'm wondering if there might be three states, where the third > state is writable. > > > Air/brass would give very small differences in signal, > > I was thinking in that case it would be open/short circuit. > _______________________________________________ > freebsd-questions@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-questions > To unsubscribe, send any mail to " > freebsd-questions-unsubscribe@freebsd.org" >