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=DKIM_SIGNED,DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS,HTML_MESSAGE,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 9545a32b for ; Fri, 25 Oct 2019 22:55:17 +0000 (UTC) Received: by minnie.tuhs.org (Postfix, from userid 112) id 3730B9B629; Sat, 26 Oct 2019 08:55:16 +1000 (AEST) Received: from minnie.tuhs.org (localhost [127.0.0.1]) by minnie.tuhs.org (Postfix) with ESMTP id 5949C93D2D; Sat, 26 Oct 2019 08:54:59 +1000 (AEST) Authentication-Results: minnie.tuhs.org; dkim=pass (2048-bit key; unprotected) header.d=bsdimp-com.20150623.gappssmtp.com header.i=@bsdimp-com.20150623.gappssmtp.com header.b="mqtK19VU"; dkim-atps=neutral Received: by minnie.tuhs.org (Postfix, from userid 112) id 20E3C93D2D; Sat, 26 Oct 2019 08:54:57 +1000 (AEST) Received: from mail-qt1-f195.google.com (mail-qt1-f195.google.com [209.85.160.195]) by minnie.tuhs.org (Postfix) with ESMTPS id 6B5C393D1B for ; Sat, 26 Oct 2019 08:54:56 +1000 (AEST) Received: by mail-qt1-f195.google.com with SMTP id t8so5692211qtc.6 for ; Fri, 25 Oct 2019 15:54:56 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bsdimp-com.20150623.gappssmtp.com; s=20150623; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=1wIuGoX7K9dqVAjGJWuWizWY5CuKcHVKEOTt5Q+1SyY=; b=mqtK19VUytpg7Lyuc0MZQc56T8Rt2tX4oONTOreEv3oNbxmPGG7bc8W0dXxPIBTZhR O8WsAVxO3JoG/7aUDziPMQP4GiaZZyxLOUr5XV+alVUJBuAyN62oSjuYEAEcLnJJWgo7 TQKqQS/Jrk8uRXH3Tg+QD4UcKRHU/7luYD6aPCvlQUflXGnQ7ZnU4zlVlOAvyJpNdOXi tfOBWh8fjWDPOqcGj/b5OmkeOVTYYzgLvQQag3RYYB5AuMmcEEi/ohZk7LO7OCbBE2w5 f47N2DTOKBYIhQX+b+/I2i8+EWYW/9z2OKvohJmyGenNgvm3+CzTTeZ48bjSVsu2DqcX JKJA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=1wIuGoX7K9dqVAjGJWuWizWY5CuKcHVKEOTt5Q+1SyY=; b=pRWoVgB80QqtQT7jHLmhG6qjSQoTBA5TZ7X7+kq2WkATOoe2lvfh7AKpglkuLpyeUB 0rnAp9VFIv8eRkWw0Ek1M1wrZ/t2SLepG6eqr5QDfShs/ConrDalISrbreKYZ6XK2vKC toesjJVgagI4sv+hETiZbrVg2Vo8lUEjzxOPm/fbW2AE2krO19bxHDlnqguSLbRBIcBq kEVm9VG5dq9sMdaiBO1m0gzz0UG1VplNbe1BXnLEdbAd13IEJe6NivlOWWuHUmAHWhP8 vSeeeqNPNPEfAqRzN5HWxN1bxHdMdO+Hb7rY6cN5X1IEXJ9XmbebEsBa02y+hjh3DbiV BpmQ== X-Gm-Message-State: APjAAAUGmBcYLLkqkx2Lw1wpB1EA1WyzKQG9T5g9E7sfrmqNb1FWM/ui +JK2RzYXH6Pt7FIJVMReSlwkymhB/UQPp7C8qaWhUbHTx+U= X-Google-Smtp-Source: APXvYqxfsiHq+n/m7qD5x0CtPYxGuhsmDMB8o9Z249+1C2ZAUaFYF4hL8gvol8UQX6tUG6phCDdxRBlkfm6ubSvLwZ8= X-Received: by 2002:aed:3be9:: with SMTP id s38mr5680115qte.175.1572044095424; Fri, 25 Oct 2019 15:54:55 -0700 (PDT) MIME-Version: 1.0 References: <20191021062242.GA91599@indra.papnet.eu> <20191022180705.GD51849@server.rulingia.com> <7455e361-b2fd-96b3-b9cd-37730f9aeed7@mhorton.net> <9f77f0d4cba8e6bc1f6fb9b5e26e883a@firemail.de> <496001dc0ab086a1e2d6d3a5f47dc5f1@bl.org> In-Reply-To: From: Warner Losh Date: Fri, 25 Oct 2019 16:54:43 -0600 Message-ID: To: Arthur Krewat Content-Type: multipart/alternative; boundary="000000000000e120f80595c40957" Subject: Re: [TUHS] PDP-7 UNIX filesystem 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: , Cc: TUHS main list Errors-To: tuhs-bounces@minnie.tuhs.org Sender: "TUHS" --000000000000e120f80595c40957 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable On Fri, Oct 25, 2019, 3:35 PM Arthur Krewat wrote: > On 10/25/2019 5:08 PM, Michael Kj=C3=B6rling wrote: > > The only thing resembling "deprecation" of dd that I'm aware of is the > > recommendation I saw many years ago to not use it to copy potentially > > problematic storage media (for data recovery), but to use ddrescue for > > that purpose instead. The reason for this is that with conv=3Dnoerror > > (without which it'd simply abort if it encounters an I/O error), dd > > would simply skip past data in the input that it can't read, but not > > adjust any offsets in the output, which wreaks havoc with anything > > where offsets matter (such as in file system metadata). > > Which is where conv=3Dsync,noerror comes in. Of course, I have no freakin= ' > idea what version of UNIX that came into being. ;) > Ddrescue tries multiple times with different sizes, which dd doesn't do. Warner art k. > > > --000000000000e120f80595c40957 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable


On Fri, Oct 25, 2019, 3:35 PM Arthur Krewat <krewat@kilonet.net> wrote:
=
On 10/25/2019 5:08 PM, Michael Kj=C3=B6rling= wrote:
> The only thing resembling "deprecation" of dd that I'm a= ware of is the
> recommendation I saw many years ago to not use it to copy potentially<= br> > problematic storage media (for data recovery), but to use ddrescue for=
> that purpose instead. The reason for this is that with conv=3Dnoerror<= br> > (without which it'd simply abort if it encounters an I/O error), d= d
> would simply skip past data in the input that it can't read, but n= ot
> adjust any offsets in the output, which wreaks havoc with anything
> where offsets matter (such as in file system metadata).

Which is where conv=3Dsync,noerror comes in. Of course, I have no freakin&#= 39;
idea what version of UNIX that came into being. ;)

Ddrescue tries multiple t= imes with different sizes, which dd doesn't do.
=
Warner=C2=A0

<= div dir=3D"auto">
art k.


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