From mboxrd@z Thu Jan 1 00:00:00 1970 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on inbox.vuxu.org X-Spam-Level: X-Spam-Status: No, score=-0.8 required=5.0 tests=DKIM_INVALID,DKIM_SIGNED, MAILING_LIST_MULTI,RCVD_IN_DNSWL_NONE autolearn=ham autolearn_force=no version=3.4.4 Received: (qmail 3857 invoked from network); 23 Aug 2020 09:09:18 -0000 Received: from minnie.tuhs.org (45.79.103.53) by inbox.vuxu.org with ESMTPUTF8; 23 Aug 2020 09:09:18 -0000 Received: by minnie.tuhs.org (Postfix, from userid 112) id 877819CA54; Sun, 23 Aug 2020 19:09:13 +1000 (AEST) Received: from minnie.tuhs.org (localhost [127.0.0.1]) by minnie.tuhs.org (Postfix) with ESMTP id 0F0A49CA47; Sun, 23 Aug 2020 19:08:41 +1000 (AEST) Authentication-Results: minnie.tuhs.org; dkim=fail reason="signature verification failed" (2048-bit key; secure) header.d=hamartun.priv.no header.i=@hamartun.priv.no header.b="mA/E4viD"; dkim-atps=neutral Received: by minnie.tuhs.org (Postfix, from userid 112) id 34F7E93D64; Sun, 23 Aug 2020 19:08:22 +1000 (AEST) X-Greylist: delayed 593 seconds by postgrey-1.36 at minnie.tuhs.org; Sun, 23 Aug 2020 19:08:19 AEST Received: from barsoom.hamartun.priv.no (barsoom.hamartun.priv.no [193.71.27.8]) by minnie.tuhs.org (Postfix) with ESMTPS id C44EE93D61; Sun, 23 Aug 2020 19:08:19 +1000 (AEST) Received: from thuvia.hamartun.priv.no (thuvia.hamartun.priv.no [IPv6:2001:8c0:c904:10::7]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)) (No client certificate requested) by barsoom.hamartun.priv.no (Postfix) with ESMTPS id 4BZ8L704zkzG2dD; Sun, 23 Aug 2020 10:58:22 +0200 (CEST) Authentication-Results: barsoom.hamartun.priv.no; arc=none smtp.remote-ip=2001:8c0:c904:10::7 ARC-Seal: i=1; a=rsa-sha256; d=hamartun.priv.no; s=barsoom; t=1598173103; cv=none; b=PZyzy8Kq4iSiiwicsrnKJPOuY9dTwpUL65NsCncuUIpk1Oj8+MfcHBcwqiMiuI4iupClhGn/SIaheq6zNpmSMkjYRZxtGTuv25Pj2O19XjPSPuM6yl5jM/FUnjk4DbVtmSyC8PfJZ2e9QBZmWFGdTHCpTdfzuZQSEKZipAYrnxE= ARC-Message-Signature: i=1; a=rsa-sha256; d=hamartun.priv.no; s=barsoom; t=1598173103; c=relaxed/simple; bh=iztZ5hPR+ZJXa2nYHzyRlweK8lw9b7Mw6/1ie2XO/G4=; h=DKIM-Signature:Received:From:To:Cc:Subject:References:Date: In-Reply-To:Message-ID:User-Agent:MIME-Version:Content-Type; b=vsOF+zAnrEK1NcvntqOOEuBaKgQiz+UbqB2qlRnkE04fE1/6LyLyf/kQvd0xpDOpH/LYmzsFwv/6yr+3RrjTbs9BFMHs6Xw1/dIrKB0n7OIOCbwFez7ibE6AKMEFJG4n4gDIhUCVW+j67S27J2dRyBccfECd2rpDC/Acf/sx+SM= ARC-Authentication-Results: i=1; barsoom.hamartun.priv.no DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=hamartun.priv.no; s=20200727; t=1598173103; bh=iztZ5hPR+ZJXa2nYHzyRlweK8lw9b7Mw6/1ie2XO/G4=; h=From:To:Cc:Subject:References:Date:In-Reply-To; b=mA/E4viDtUnhKsoKgosjYJvPmDED76mz4hE6GEgCokLdZejoqc2pp+NmNQmw0bhcK PbN/RYEYMIy0UckJcIxkQCc6iFbo181VoH0MpVeW7AzjbC6BjRDgEe8IZEhgN98KsI rYM07KX0UBaB7KG6AIC3KGKhSFLkYSEiSsVwzWiTNItJzrMQEicw6tMR7Lil+JadoP zjKgnOdWEs7IQWE+C1X/DcoxCo5E3x3Jqb0GawXx5e3UXe8sjMP2NILI3Upr2qjiY/ 9c7SKgUe+fE3P5MF42rCPsqtPezh0IWXnkoqsweLmYYbq49pLNxr7K1wvPMa58i7AD qjSXKL38Ur25g== Received: by thuvia.hamartun.priv.no (Postfix, from userid 501) id 2997E4DED5; Sun, 23 Aug 2020 10:58:20 +0200 (CEST) To: Robert Clausecker References: <20200711203020.GA1884@minnie.tuhs.org> <202007120222.06C2MtdJ140032@tahoe.cs.Dartmouth.EDU> <738ab925-586b-4921-b891-a4ec20348d4c@localhost> <20200712145822.GA72854@fuz.su> Date: Sun, 23 Aug 2020 10:58:19 +0200 In-Reply-To: <20200712145822.GA72854@fuz.su> (Robert Clausecker's message of "Sun, 12 Jul 2020 16:58:22 +0200") Message-ID: User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/25.3 (berkeley-unix) MIME-Version: 1.0 Content-Type: text/plain Subject: Re: [TUHS] Monitoring by loudspeaker X-BeenThere: tuhs@minnie.tuhs.org X-Mailman-Version: 2.1.26 Precedence: list List-Id: The Unix Heritage Society mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , From: Tom Ivar Helbekkmo via TUHS Reply-To: Tom Ivar Helbekkmo Cc: coff@tuhs.org, TUHS@tuhs.org Errors-To: tuhs-bounces@minnie.tuhs.org Sender: "TUHS" Robert Clausecker writes: > When the computer is in a tight endless loop, the accumulator takes the > same series of values every time it's in the loop. Thus, instead of > white noise you get a sound whose frequency is the clock frequency of > the machine divided by the number of cycles spent by one loop iteration. A buddy and I did something somewhat related back in the early eighties, when we were teaching ourselves programming, using, among other things, his Tandy TRS-80 home computer. We discovered that a cheap "transistor radio", sitting close to the computer, would be affected by the noise generated by it, and then we figured out that if we didn't tune it to a radio station, we'd get only the noise. Leaving that on as we worked on a program, we got familiar with the sound of the code, and became able to follow the execution by the changing patterns -- and if it did get stuck in a loop somewhere, we'd not only hear it, but we would also have a pretty good idea where it happened. -tih -- Most people who graduate with CS degrees don't understand the significance of Lisp. Lisp is the most important idea in computer science. --Alan Kay