From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on inbox.vuxu.org X-Spam-Level: X-Spam-Status: No, score=-0.8 required=5.0 tests=DKIM_ADSP_CUSTOM_MED, DKIM_INVALID,DKIM_SIGNED,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,HTML_MESSAGE,MAILING_LIST_MULTI autolearn=ham autolearn_force=no version=3.4.4 Received: from minnie.tuhs.org (minnie.tuhs.org [50.116.15.146]) by inbox.vuxu.org (Postfix) with ESMTP id 84B2E2007B for ; Thu, 5 Dec 2024 18:22:24 +0100 (CET) Received: from minnie.tuhs.org (localhost [IPv6:::1]) by minnie.tuhs.org (Postfix) with ESMTP id 16AA943E10; Fri, 6 Dec 2024 03:22:20 +1000 (AEST) Received: from mail-pj1-x1034.google.com (mail-pj1-x1034.google.com [IPv6:2607:f8b0:4864:20::1034]) by minnie.tuhs.org (Postfix) with ESMTPS id 69F7843E0E for ; Fri, 6 Dec 2024 03:22:16 +1000 (AEST) Received: by mail-pj1-x1034.google.com with SMTP id 98e67ed59e1d1-2ee86a1a92dso883852a91.1 for ; Thu, 05 Dec 2024 09:22:16 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1733419335; x=1734024135; darn=tuhs.org; h=to:subject:message-id:date:from:in-reply-to:references:mime-version :from:to:cc:subject:date:message-id:reply-to; bh=56fqDnB9YaTbyWA3N3l8kFcAB26lixBK/Qgg1hSpEZU=; b=hCaa9MUDquMmkFn+kCg2twkRv+/aF4DJ1ySLh058kFByDezpB5SMQ78KuyuBPGrXqz Ng2crR9YUVHa7yL0rzfck2VnfWX7VMA7TVdkTd30KW85wPiYzuHeH6mvve4HVZSaw/9v 43zWWoU/0W5XoPiaA+6bcnut3JHzLEeF314yREQDZ1rygGV9yLZxCOU+GWMCCsb/7Bzi N58X3FZjPM5XNDkGJZlf+hp7pLqLBgcjRmMU1di51CrAgkTqaQGWYaSlIRZT+qOtPlof xgAoDAxlP63Kdq9gGixWHM/qtCh5vwGGW4LY99xSJTdr1KWtBcwTyLTocOKy+Oq387uf fwFw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1733419335; x=1734024135; h=to:subject:message-id:date:from:in-reply-to:references:mime-version :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=56fqDnB9YaTbyWA3N3l8kFcAB26lixBK/Qgg1hSpEZU=; b=vqX9uXt5x6owFnwwJl7cnEN0WscBNYyttNO9HqZ1ENC4lJcG2+fCDvwDxYj94hlTWq jDjLCAgiHpMsYCICK30sBwvWhtHcJzmSXNgwLSsG1vsm2v7kOVzwOYgPHezF2cbvaVYu XuU33OaFTIj4LnSlJH03pPT1ABxAx8a9dX3AmNnt9mP+VuxsZT/kyDmFx94IX9WI4aYx s8X6nT2cFkIS0cmpSs+FI+8hzweEm9p/VX6bMFsCqNpWZNql5em48nyCRpVzCoUSb79c R37HA8AUE8apyAEEC1q2G1NV8xOGvcVWvm4yVfcRfE6n3URXmjMbDRy1daDdoNSeq4fA OtFw== X-Gm-Message-State: AOJu0YwTj3RJDcL9rxDHyMG2ZX4aQ9QJ3/ZgB4Qc/0N2tg7DCaMXO5YD +64pq+fJX3w8IKRQsHU+TdaCEvUocl4VNFQXygO0zOWqWIRujLACZjU1UJnSCwa8lmRccc2qp3+ vQZBICcxaF2IeJFt6iIg9XcbXkalbnw== X-Gm-Gg: ASbGncsAWKxGD9258MwgzCZxTRhhboNx/JNqsZrWqA9wavhwy562rspzRgUF0wzBL4v 9IqV/c0cph5Us/SYof8x3PXdTt3JhVPh98w== X-Google-Smtp-Source: AGHT+IFnJ+7xy0YDsmf/nW2smSahI7x0LeSkcNsfq/G9K69lvQBQtdcSlcrfQ4YGanQw4lGvXwt83gUEtPFjquY7xF8= X-Received: by 2002:a17:90b:52c4:b0:2ee:8e75:4aeb with SMTP id 98e67ed59e1d1-2ef0121357amr17579907a91.17.1733419335594; Thu, 05 Dec 2024 09:22:15 -0800 (PST) MIME-Version: 1.0 References: <568FD44F-01FB-441B-846B-7D42C3A8E1FB@canb.auug.org.au> <20241205030843.8552FAB1EDA5@ary.qy> <32bf4263-277d-8c8b-6bf7-e33df04a2c3c@taugh.com> In-Reply-To: From: Paul Winalski Date: Thu, 5 Dec 2024 12:22:05 -0500 Message-ID: To: tuhs@tuhs.org Content-Type: multipart/alternative; boundary="000000000000bebb700628892372" Message-ID-Hash: H6INV2A2DUMYYEI2IXEWVUJOGRSIWGDV X-Message-ID-Hash: H6INV2A2DUMYYEI2IXEWVUJOGRSIWGDV X-MailFrom: paul.winalski@gmail.com X-Mailman-Rule-Misses: dmarc-mitigation; no-senders; approved; emergency; loop; banned-address; member-moderation; header-match-tuhs.tuhs.org-0; nonmember-moderation; administrivia; implicit-dest; max-recipients; max-size; news-moderation; no-subject; digests; suspicious-header X-Mailman-Version: 3.3.6b1 Precedence: list Subject: [TUHS] Re: Pipes (was Re: After 50 years, what has the Impact of Unix been?) List-Id: The Unix Heritage Society mailing list Archived-At: List-Archive: List-Help: List-Owner: List-Post: List-Subscribe: List-Unsubscribe: --000000000000bebb700628892372 Content-Type: text/plain; charset="UTF-8" Regarding pipes and pipe-like interprocess communications facilities in other operating systems, VMS has always had a pipe-like communications pseudo-devices called mailboxes. The main difference between Unix pipes and VMS mailboxes is that pipes have distinct read-only and write-only file descriptors. Mailboxes do not--channels (VMS-speak for file descriptors) assigned to a mailbox can be used for both reading and writing. This means that it is not possible to do "broken pipe"-type detection on a mailbox. This very much restricts the usefulness of mailboxes. I wrote a true pipe device driver for VMS as part of the DEC Shell product (a port of the Unix Bourne shell to VMS). -Paul W. --000000000000bebb700628892372 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable
Regarding pipes and pipe-like interprocess communicat= ions facilities in other operating systems, VMS has always had a pipe-like = communications pseudo-devices called mailboxes.=C2=A0 The main difference b= etween Unix pipes and VMS mailboxes is that pipes have distinct read-only a= nd write-only file descriptors.=C2=A0 Mailboxes do not--channels (VMS-speak= for file descriptors) assigned to a mailbox can be used for both reading a= nd writing.=C2=A0 This means that it is not possible to do "broken pip= e"-type detection on a mailbox.=C2=A0 This very much restricts the use= fulness of mailboxes.

I wrote a true pipe devi= ce driver for VMS as part of the DEC Shell product (a port of the Unix Bour= ne shell to VMS).

-Paul W.

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