From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on inbox.vuxu.org X-Spam-Level: X-Spam-Status: No, score=-0.8 required=5.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,RCVD_IN_DNSWL_NONE autolearn=ham autolearn_force=no version=3.4.2 Received: from minnie.tuhs.org (minnie.tuhs.org [45.79.103.53]) by inbox.vuxu.org (OpenSMTPD) with ESMTP id 3d1e8a67 for ; Wed, 15 Jan 2020 07:12:16 +0000 (UTC) Received: by minnie.tuhs.org (Postfix, from userid 112) id 816079BFEA; Wed, 15 Jan 2020 17:12:15 +1000 (AEST) Received: from minnie.tuhs.org (localhost [127.0.0.1]) by minnie.tuhs.org (Postfix) with ESMTP id 258679B898; Wed, 15 Jan 2020 17:11:02 +1000 (AEST) Received: by minnie.tuhs.org (Postfix, from userid 112) id D013C9B898; Wed, 15 Jan 2020 17:10:59 +1000 (AEST) Received: from fourwinds.com (fourwinds.com [63.64.179.162]) by minnie.tuhs.org (Postfix) with ESMTPS id 212E293D06 for ; Wed, 15 Jan 2020 17:10:55 +1000 (AEST) Received: from darkstar.fourwinds.com (localhost [127.0.0.1]) by fourwinds.com (8.15.2/8.15.2) with ESMTPS id 00F7Asg41716617 (version=TLSv1.3 cipher=TLS_AES_256_GCM_SHA384 bits=256 verify=NOT) for ; Tue, 14 Jan 2020 23:10:54 -0800 Received: from darkstar.fourwinds.com (jon@localhost) by darkstar.fourwinds.com (8.15.2/8.15.2/Submit) with ESMTP id 00F7AsFQ1716609 for ; Tue, 14 Jan 2020 23:10:54 -0800 Message-Id: <202001150710.00F7AsFQ1716609@darkstar.fourwinds.com> From: Jon Steinhart To: TUHS@minnie.tuhs.org In-reply-to: References: <7wsgkhgs5l.fsf@junk.nocrew.org> Comments: In-reply-to Earl Baugh message dated "Wed, 15 Jan 2020 01:34:29 -0500." MIME-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-ID: <1716550.1579072232.1@darkstar.fourwinds.com> Content-Transfer-Encoding: 8bit Date: Tue, 14 Jan 2020 23:10:53 -0800 X-JON-SPAM: local delivery Subject: Re: [TUHS] Spacewar at Bell Labs [ really paper tape readers and tangentially related things ] 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" Earl Baugh writes: > Why not build a variation of this with an Arduino? > https://www.instructables.com/id/DIY-Paper-TapePunch-Card-Maker-and-Reader/. > You could use cardboard rather than wood if it’s just a one time job. ( or scan > the tape into files and process digitally ?) > > Earl I thought that I said earlier that I had a paper tape reader here but don't remember much about it or if it ever worked. If I didn't have a huge project list and it wasn't ski season I could hook it up to a pi. More likely that I'll get to a computer museum sooner. Just to keep this UNIX-related so that Warren doesn't get cranky, I believe that this reader came out of some sort of experimental telephone exchange in our group that was decommissioned. Dave Weller was very supportive of my interests and somehow arranged for me to take much of it home as surplus equipment. Kept me in 7400-series parts and Augat wire-wrap boards for a long time. While there was no way that I could have kept the thing, I wish that I had the magnetic drum memory because it was so cool from an industrial art perspective. Heinz may remember more about this than I do because he actually worked on this project, but our department developed what I believe was the first all-digital telephone exchange that used digital filtering (Hal Alles and Jim Kaiser were in the group). I think that it had a pair of PDP-11/10s in it, and a bigger PDP-11 as a supervisory machine that ran UNIX. I have vague memories of Heinz and Carl poring over huge C program listings. I also remember that there was a bug in the long-distance code where it wasn't sending out the ST tone that ended up taking all of the key pulse senders in the Berkeley Heights telephone exchange that provided the trunk line to our lab off line as they didn't have timeouts and needed to be manually reset. But hey, we were the phone company too so what could they do about it? Oh, I think that the PDP-11/10s were used because we tried to use LSI-11s but those turned out to be useless because of the way that DEC did the DRAM refresh; it wasn't interleaved, they just stopped everything every so many ms and refreshed everything. Non-starter for real-time systems. And another thought, this machine may have been why Heinz wrote MERT. I was gone before this system was completed so I have no idea how it fared and how many of the ideas were incorporated into production systems. Oh, yeah, I think that it was called the SS1 for Slave Switch 1. Jon