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=-1.1 required=5.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FROM,MAILING_LIST_MULTI,RCVD_IN_DNSWL_NONE autolearn=ham autolearn_force=no version=3.4.4 Received: (qmail 25840 invoked from network); 21 Sep 2020 18:40:35 -0000 Received: from minnie.tuhs.org (45.79.103.53) by inbox.vuxu.org with ESMTPUTF8; 21 Sep 2020 18:40:35 -0000 Received: by minnie.tuhs.org (Postfix, from userid 112) id B586E9CBFE; Tue, 22 Sep 2020 04:40:29 +1000 (AEST) Received: from minnie.tuhs.org (localhost [127.0.0.1]) by minnie.tuhs.org (Postfix) with ESMTP id EEF0693D33; Tue, 22 Sep 2020 04:40:14 +1000 (AEST) Authentication-Results: minnie.tuhs.org; dkim=pass (2048-bit key; unprotected) header.d=gmail.com header.i=@gmail.com header.b="k+m9xE81"; dkim-atps=neutral Received: by minnie.tuhs.org (Postfix, from userid 112) id 3C98F93D33; Tue, 22 Sep 2020 04:40:13 +1000 (AEST) Received: from mail-vs1-f43.google.com (mail-vs1-f43.google.com [209.85.217.43]) by minnie.tuhs.org (Postfix) with ESMTPS id A68BB93D06 for ; Tue, 22 Sep 2020 04:40:12 +1000 (AEST) Received: by mail-vs1-f43.google.com with SMTP id y194so8737718vsc.4 for ; Mon, 21 Sep 2020 11:40:12 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:in-reply-to:references:from:date:message-id:subject:to; bh=Us94IoSeQC1MeVKtqAYBhh69+8dD6j5fH+4TrbIu+eA=; b=k+m9xE81x0AX/CQqP1GOV+zTCf5gAKeYX4+aAUm3hlxwbpiz2JhloX2uSkdalvCxLR TdQUG89yv0mOMFNXE8aXljPwGPwPu0h5JvXdB4Rvj1XVfQqIORHyVptRuEkCZHBc+reM PJwxaA4brtmLwfSeJzph+4dEJXzO0Pt8ZcaMwa8j4r7doxfgYaIycpJvtIoZCTui/0/h IYRTpjTP7eFnDkU5SwR6xFnjJYtKK0Zfpmj9y5vqLms4bHaU4gFeLBB+aG7reKBrPEsi ML98r3o5cuipW6IRGV/Jf7Dg4hXD03xT+PfSlXifp/bmfk6qJK+XHuxyiL5Bhk9JyhTC xtSw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:in-reply-to:references:from:date :message-id:subject:to; bh=Us94IoSeQC1MeVKtqAYBhh69+8dD6j5fH+4TrbIu+eA=; b=CQITfApBviEr0gUqA6Ib0SiFDFG8pcXVG3LYBx2i+DCDNmH34zudsOMM6VMNjIDJdM mzh53f+5kItkyX48PHZiY1hC7HwJl2Qrei5tKqgl6I9M50XevnK3hhZUGyQKkgo5XqAS +/VWKkTxWaXbHVuWDU8v+6j6hhXtBGdtSYiaQ16kgPbavldle117DL/1g21Wk+mj/zMQ wZDDkREpKlL0u6JDBlpS0Ew9HqlVCI2+6r7R06IBLFt6/njH9VtXFKfYc55dSEhBTnfx SsBeLktOsyhRL5q3DAClkoswDY6QZVs4tnitz+i+60XI6fhRTCPjTu7MaLY8nFjg+oJY EriQ== X-Gm-Message-State: AOAM533vqjUWMsP9PLKQlidSjm5pBcueHr0piYVOM1AYCHWg3fLfJajZ 9jDRz1MeGm6G3ht1fFUfnS73vWeiY2PLreISu2DrT05QUx4= X-Google-Smtp-Source: ABdhPJxSstsuzVcMRbu0ssdpR5OLNyF8QfCRYXNEhiIrT2NenaH1MzUXpLJH1Zh3xiIZsgMFV3AqmnvPifB4PQyIC3M= X-Received: by 2002:a67:2f0a:: with SMTP id v10mr1173861vsv.7.1600713611396; Mon, 21 Sep 2020 11:40:11 -0700 (PDT) MIME-Version: 1.0 Received: by 2002:ab0:6258:0:0:0:0:0 with HTTP; Mon, 21 Sep 2020 11:40:10 -0700 (PDT) In-Reply-To: References: <20200920230057.C5D1A4422E@lignose.oclsc.org> From: Paul Winalski Date: Mon, 21 Sep 2020 14:40:10 -0400 Message-ID: To: The Eunuchs Hysterical Society Content-Type: text/plain; charset="UTF-8" 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" VAX/VMS was the first operating system I encountered where 0 was not a valid program address. As was mentioned previously, address space on early machines was too precious to throw away a whole page of it just to catch bad null pointer references. I once saw a C program that depended on 0 being a valid pointer address, and on a 0x00 byte being at memory address 0. The program had a bunch of char* pointers that were used in a printf() call, something like: printf("%s%s%s%s\n", a, b, c, d); If you didn't want, say, the third string printed, you assigned NULL to variable c. That caused c to point to location 0, and printf() interpreted the 0 byte as the empty string "". It was hell getting this program to work on the VAX. -Paul W.