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=-1.0 required=5.0 tests=HTML_MESSAGE, MAILING_LIST_MULTI,RCVD_IN_DNSWL_NONE autolearn=ham autolearn_force=no version=3.4.4 Received: (qmail 11446 invoked from network); 12 Jul 2020 20:11:22 -0000 Received: from minnie.tuhs.org (45.79.103.53) by inbox.vuxu.org with ESMTPUTF8; 12 Jul 2020 20:11:22 -0000 Received: by minnie.tuhs.org (Postfix, from userid 112) id 7A97D9C1D4; Mon, 13 Jul 2020 06:11:17 +1000 (AEST) Received: from minnie.tuhs.org (localhost [127.0.0.1]) by minnie.tuhs.org (Postfix) with ESMTP id 581D89C17A; Mon, 13 Jul 2020 06:10:21 +1000 (AEST) Received: by minnie.tuhs.org (Postfix, from userid 112) id F0CF09C17A; Mon, 13 Jul 2020 06:10:17 +1000 (AEST) Received: from cfcl.com (cpepool4cmts2-144.sanbrunocable.com [24.143.248.144]) by minnie.tuhs.org (Postfix) with ESMTP id 98D3994585 for ; Mon, 13 Jul 2020 06:10:17 +1000 (AEST) Received: from spot.local (spot.local [IPv6:fe80::108f:61b6:e9ea:e7ae]) by cfcl.com (Postfix) with ESMTP id D648A113FB23 for ; Sun, 12 Jul 2020 13:10:16 -0700 (PDT) From: Rich Morin Content-Type: multipart/alternative; boundary="Apple-Mail=_D3B68DAE-1499-4BAB-AE19-C4E45D173AEA" Mime-Version: 1.0 (Mac OS X Mail 13.0 \(3608.40.2.2.4\)) Message-Id: <58A78A18-4CD1-4338-A49F-CA2140070328@cfcl.com> References: <8cf76d2d-c598-9c5c-3bcc-8b3e0518e313@bitsavers.org> To: TUHS main list Date: Sun, 12 Jul 2020 13:10:15 -0700 X-Mailer: Apple Mail (2.3608.40.2.2.4) Subject: [TUHS] Fwd: 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: , Errors-To: tuhs-bounces@minnie.tuhs.org Sender: "TUHS" --Apple-Mail=_D3B68DAE-1499-4BAB-AE19-C4E45D173AEA Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=us-ascii On the CDC 3800, the top three bits of the accumulator were scaled and = summed by a set of three resistors, then fed into the console speaker. = Generally, this produced noise of very little interest (except to = indicate that the machine was running). However, when I ran my Shellsort = (https://en.wikipedia.org/wiki/Shellsort = ), the speaker made a very = distinctive sound. It was a series of rising tones whose durations got = shorter and shorter. Something like Vwooooooooooop, Vwooooooop, = Vwooooop, Vroop, ... -r --Apple-Mail=_D3B68DAE-1499-4BAB-AE19-C4E45D173AEA Content-Transfer-Encoding: 7bit Content-Type: text/html; charset=us-ascii On the CDC 3800, the top three bits of the accumulator were scaled and summed by a set of three resistors, then fed into the console speaker.  Generally, this produced noise of very little interest (except to indicate that the machine was running).

However, when I ran my Shellsort (https://en.wikipedia.org/wiki/Shellsort), the speaker made a very distinctive sound.  It was a series of rising tones whose durations got shorter and shorter.   Something like Vwooooooooooop, Vwooooooop, Vwooooop, Vroop, ...

-r

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