From mboxrd@z Thu Jan 1 00:00:00 1970 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=DKIM_INVALID,DKIM_SIGNED, MAILING_LIST_MULTI,RCVD_IN_DNSWL_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.2 Received: (qmail 28571 invoked from network); 3 Apr 2020 18:34:07 -0000 Received-SPF: pass (minnie.tuhs.org: domain of minnie.tuhs.org designates 45.79.103.53 as permitted sender) receiver=inbox.vuxu.org; client-ip=45.79.103.53 envelope-from= Received: from minnie.tuhs.org (45.79.103.53) by inbox.vuxu.org with UTF8ESMTPZ; 3 Apr 2020 18:34:07 -0000 Received: by minnie.tuhs.org (Postfix, from userid 112) id 2879F9D97B; Sat, 4 Apr 2020 04:33:56 +1000 (AEST) Received: from minnie.tuhs.org (localhost [127.0.0.1]) by minnie.tuhs.org (Postfix) with ESMTP id C8CFA9D958; Sat, 4 Apr 2020 04:33:25 +1000 (AEST) Authentication-Results: minnie.tuhs.org; dkim=fail reason="signature verification failed" (1024-bit key; unprotected) header.d=planet.nl header.i=@planet.nl header.b="CJKTyk1q"; dkim-atps=neutral Received: by minnie.tuhs.org (Postfix, from userid 112) id 1674F9D710; Sat, 4 Apr 2020 04:33:23 +1000 (AEST) Received: from cpsmtpb-ews01.kpnxchange.com (cpsmtpb-ews01.kpnxchange.com [213.75.39.4]) by minnie.tuhs.org (Postfix) with ESMTP id 9F3589D58E for ; Sat, 4 Apr 2020 04:33:18 +1000 (AEST) Received: from cpsps-ews16.kpnxchange.com ([10.94.84.197]) by cpsmtpb-ews01.kpnxchange.com with Microsoft SMTPSVC(8.5.9600.16384); Fri, 3 Apr 2020 20:33:16 +0200 X-Brand: 7abm2Q== X-KPN-SpamVerdict: e1=0;e2=0;e3=0;e4=(e1=10;e3=10;e2=11;e4=10);EVW:Whi te;BM:NotScanned;FinalVerdict:Clean X-CMAE-Analysis: v=2.3 cv=WNfkokkR c=1 sm=1 tr=0 cx=a_idp_e a=dZ5u/0G9QtS9WKCcNUBnHQ==:117 a=soxbC+bCkqwFbqeW/W/r+Q==:17 a=x1i13A_MHe4A:10 a=IkcTkHD0fZMA:10 a=cl8xLZFz6L8A:10 a=-RmiO33T0h8pSxjr70oA:9 a=4LHA2JW1_8s1K6pY:21 a=nieuh2UQD4s6ARrB:21 a=QEXdDO2ut3YA:10 X-CM-AcctID: kpn@feedback.cloudmark.com Received: from smtp.kpnmail.nl ([195.121.84.13]) by cpsps-ews16.kpnxchange.com over TLS secured channel with Microsoft SMTPSVC(8.5.9600.16384); Fri, 3 Apr 2020 20:33:16 +0200 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=planet.nl; s=planet01; h=to:date:message-id:subject:mime-version:content-type:from; bh=32QZE8p+d4GG5PlmvkpPDz1umyXeWL1HWBM31z3hB+0=; b=CJKTyk1qQ+IfD1vTGEdogvRBCvpcBTbzndSUhtejuot9/nYA3EJJrpS0sQ7s/p87q4Xxfe/8IGPLw lA0YcO/h1jBMLfi3uPhLe035+QHQJSCHZKW0RuodCWvoRhKYaGvQHe2KhequamdHzJz8EGE1RdC0w2 irUe6e1Elev67htc= X-KPN-VerifiedSender: Yes X-CMASSUN: 33|Iel/RSDbWwQxvTB34sb7xuXFTNWKIOGv5/O6wQbF25hd1DglpdkeobHE0hq+12D zyZB86+JjqyEAwSME2hEiNg== X-Originating-IP: 80.101.112.122 Received: from mba2.fritz.box (sqlite.xs4all.nl [80.101.112.122]) by smtp.kpnmail.nl (Halon) with ESMTPSA id 95244db1-75d9-11ea-a1a6-005056998788; Fri, 03 Apr 2020 20:33:16 +0200 (CEST) From: Paul Ruizendaal Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Mime-Version: 1.0 (Mac OS X Mail 12.4 \(3445.104.11\)) Message-Id: <1088CB8E-C53F-474B-9831-9890F75E5882@planet.nl> Date: Fri, 3 Apr 2020 20:33:15 +0200 To: TUHS main list X-Mailer: Apple Mail (2.3445.104.11) X-OriginalArrivalTime: 03 Apr 2020 18:33:16.0341 (UTC) FILETIME=[57288650:01D609E6] X-RcptDomain: minnie.tuhs.org Subject: [TUHS] Research PBX legacy 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" About a year ago the Research telephone switch came up on this list. Rob Pike wrote: "But the PBX story is correct. To demonstrate how message passing was a = good model for a switching system, in particular to make a point to the switching systems division of Bell Labs/AT&T, Ken and Joe bought a commercial PBX and swapped out its processor for a PDP-11/23 (I think), = and programmed it up. It was just before I arrived there but I was given the impression it had the desired strategic influence on Indian Hill. The feature we all loved it for was that instead of ringing the phone in the Unix room when you got a call, it would announce your name through = the voice synthesizer: "Phone call for Ken." "Phone call for Joe". One = rapidly stopped even hearing the announcement if it didn't end with your = name.=E2=80=9D I=E2=80=99ve been having an off list discussion with Bill Marshall and = this PBX was influential in another way as well. First of all, Bill can confirm that it indeed was a 11/23, the same = racks were used for Datakit switches. He also remembered that the = software for this PDP-11 went by the nickname of =E2=80=9CTPC=E2=80=9D - = for Tiny Phone Company. Lee McMahon was on the team writing TPC. The first software for the Datakit switch was written by Greg Chesson = and was called =E2=80=9CCMC=E2=80=9D (for =E2=80=98Common Control=E2=80=99= ). There are still some references to CMC in the 8th Edition source = code. This first software was later replaced by new code designed by Lee = McMahon that was modelled after TPC. This new code was named =E2=80=9CTDK=E2= =80=9D. This, too, can be seen in the 8th Edition source. The TDK = protocols for building and releasing a Datakit virtual circuit appear to = have been in use into the 1990=E2=80=99s.