From: Dan Cross <crossd@gmail.com>
To: "Michael Kjörling" <michael@kjorling.se>
Cc: Computer Old Farts Followers <coff@tuhs.org>,
The Eunuchs Hysterical Society <tuhs@tuhs.org>
Subject: Re: [TUHS] Monitoring by loudspeaker (was: BTL pranks)
Date: Sun, 12 Jul 2020 09:25:34 -0400 [thread overview]
Message-ID: <CAEoi9W4HFdhO9cStrBbLaB2kiAXFZVJ7NOpjDjzZiaNAcEA_vQ@mail.gmail.com> (raw)
In-Reply-To: <738ab925-586b-4921-b891-a4ec20348d4c@localhost>
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On Sun, Jul 12, 2020 at 7:59 AM Michael Kjörling <michael@kjorling.se>
wrote:
> (This should probably be on COFF because I don't think this has much
> to do with UNIX.)
>
>
> On 11 Jul 2020 22:22 -0400, from doug@cs.dartmouth.edu (Doug McIlroy):
> > a loudspeaker hooked to the low-order bit of the accumulator played
> > gentle white noise in the background. The noise would turn into a
> > shriek when the computer got into a tight loop,
>
> How did that work? I can see how tying the low-order bit of the
> accumulator to a loudspeaker would generate white noise as the
> computer is doing work; but I fail to see how doing so would even
> somewhat reliably generate a shrieking sound when the computer is in a
> tight loop. Please, enlighten me. :-)
>
I would imagine a cap as a low-pass filter and a transistor as a poor-man's
analog comparator triggering a tape player on loop.
- Dan C.
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next prev parent reply other threads:[~2020-07-12 13:27 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-11 1:08 [TUHS] AT&T Research John P. Linderman
2020-07-11 1:32 ` Larry McVoy
2020-07-11 1:51 ` John P. Linderman
2020-07-11 15:36 ` Clem Cole
2020-07-11 20:30 ` Warren Toomey
2020-07-11 20:36 ` Jon Steinhart
2020-07-11 21:58 ` Rob Pike
2020-07-11 22:29 ` Larry McVoy
2020-07-12 7:55 ` Ed Bradford
2020-07-12 2:22 ` [TUHS] BTL pranks [was AT&T Research] Doug McIlroy
2020-07-12 11:58 ` [TUHS] Monitoring by loudspeaker (was: BTL pranks) Michael Kjörling
2020-07-12 13:25 ` Dan Cross [this message]
2020-07-12 14:58 ` Robert Clausecker
2020-07-12 16:09 ` [TUHS] Monitoring by loudspeaker Al Kossow
2020-07-12 20:10 ` [TUHS] Fwd: " Rich Morin
2020-08-23 8:58 ` [TUHS] " Tom Ivar Helbekkmo via TUHS
2020-07-23 4:13 ` [TUHS] AT&T Research scj
2020-07-23 6:02 ` [TUHS] Technical decisions based on political considerations [was Re: AT&T Research] arnold
2020-07-23 14:42 ` Larry McVoy
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