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=MAILING_LIST_MULTI, RCVD_IN_DNSWL_NONE autolearn=ham autolearn_force=no version=3.4.4 Received: (qmail 6818 invoked from network); 25 Sep 2020 14:20:21 -0000 Received: from minnie.tuhs.org (45.79.103.53) by inbox.vuxu.org with ESMTPUTF8; 25 Sep 2020 14:20:20 -0000 Received: by minnie.tuhs.org (Postfix, from userid 112) id 507049CEC7; Sat, 26 Sep 2020 00:20:14 +1000 (AEST) Received: from minnie.tuhs.org (localhost [127.0.0.1]) by minnie.tuhs.org (Postfix) with ESMTP id 4B7C49CEC6; Sat, 26 Sep 2020 00:19:32 +1000 (AEST) Received: by minnie.tuhs.org (Postfix, from userid 112) id A1E0394552; Sat, 26 Sep 2020 00:19:28 +1000 (AEST) Received: from mail.cs.dartmouth.edu (mail.cs.dartmouth.edu [129.170.212.100]) by minnie.tuhs.org (Postfix) with ESMTPS id BC8FB93D65 for ; Sat, 26 Sep 2020 00:19:27 +1000 (AEST) Received: from coolidge.cs.dartmouth.edu (coolidge.cs.dartmouth.edu [129.170.213.217]) by mail.cs.dartmouth.edu (8.15.2/8.15.2) with ESMTPS id 08PEJPbo641930 (version=TLSv1.3 cipher=TLS_AES_256_GCM_SHA384 bits=256 verify=NO) for ; Fri, 25 Sep 2020 10:19:25 -0400 Received: from coolidge.cs.dartmouth.edu (localhost [127.0.0.1]) by coolidge.cs.dartmouth.edu (8.15.2/8.15.2) with ESMTP id 08PEJPwe248912 for ; Fri, 25 Sep 2020 10:19:25 -0400 Received: (from doug@localhost) by coolidge.cs.dartmouth.edu (8.15.2/8.15.2/Submit) id 08PEJPkV248911 for tuhs@tuhs.org; Fri, 25 Sep 2020 10:19:25 -0400 From: Doug McIlroy Message-Id: <202009251419.08PEJPkV248911@coolidge.cs.dartmouth.edu> Date: Fri, 25 Sep 2020 10:19:25 -0400 To: tuhs@tuhs.org User-Agent: Heirloom mailx 12.5 7/5/10 MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Subject: Re: [TUHS] reviving a bit of WWB 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" > Turing save us from 1-complement machines! Users of Whirlwind II were warned about the quirks of -0. We were not warned, though, about integer divide with remainder 0. The result of dividing 6 by 3, for example, was binary 1.111111... - a valid answer when carried to infinity. Unfortunately, the "fractional" part was dropped. Most people used Whirlwind for floating-point computation, and blithely dismissed printed answers like 1.999999 as "roundoff errors". Doug