From owner-freebsd-arch@FreeBSD.ORG Fri Aug 31 13:18:40 2007 Return-Path: Delivered-To: arch@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 49E5216A419 for ; Fri, 31 Aug 2007 13:18:40 +0000 (UTC) (envelope-from rnsanchez@wait4.org) Received: from sumo.dreamhost.com (sumo.dreamhost.com [66.33.216.29]) by mx1.freebsd.org (Postfix) with ESMTP id 33EC213C465 for ; Fri, 31 Aug 2007 13:18:40 +0000 (UTC) (envelope-from rnsanchez@wait4.org) Received: from spunkymail-a16.dreamhost.com (sd-green-bigip-83.dreamhost.com [208.97.132.83]) by sumo.dreamhost.com (Postfix) with ESMTP id D43C717C0D6 for ; Fri, 31 Aug 2007 05:47:28 -0700 (PDT) Received: from sauron.lan.box (201-34-83-58.paemt701.dsl.brasiltelecom.net.br [201.34.83.58]) by spunkymail-a16.dreamhost.com (Postfix) with ESMTP id 2245E7CF5C; Fri, 31 Aug 2007 05:46:56 -0700 (PDT) Date: Fri, 31 Aug 2007 09:46:52 -0300 From: Ricardo Nabinger Sanchez To: Poul-Henning Kamp Message-Id: <20070831094652.0cf1f3a8.rnsanchez@wait4.org> In-Reply-To: <8412.1188553371@critter.freebsd.dk> References: <8412.1188553371@critter.freebsd.dk> Organization: SYS_WAIT4 X-Mailer: Sylpheed 2.4.4 (GTK+ 2.10.14; i386-unknown-freebsd6.1) Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Cc: arch@freebsd.org Subject: Re: Proof of concept: soundcard as console device X-BeenThere: freebsd-arch@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Discussion related to FreeBSD architecture List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 31 Aug 2007 13:18:40 -0000 On Fri, 31 Aug 2007 09:42:51 +0000 Poul-Henning Kamp wrote: > What's left to do: >=20 > * optimize transmission schema. >=20 > This can be done with two computers, a jack-jack cable > and a bit of C-coding. >=20 > The difference in sample rate between the two machines > causes off-by-one errors. I don't know of a peak > detector which interpolates can resolve this, of if we need use > oversampling in the receiver. >=20 > The two pulses can have two different polarities each, > so we can transmit two bits just that way, this could > speed up transmission by a factor of four, if we can find a way > to synchronize properly. >=20 > The two stereo channels can be used independently, > offering a doubling in speed. Sounds like a synchronization pattern could be used here, like the one used for E1 channels (resync at every 512 bits), or any other scheme for plesiochronous channels. Or taking one channel to signal when data is ready. This is simply =FCber-cool. :) --=20 Ricardo Nabinger Sanchez rnsanchez@wait4.org Powered by FreeBSD "Left to themselves, things tend to go from bad to worse."