From unknown Mon Aug 18 23:56:45 2025 X-Loop: help-debbugs@gnu.org Subject: bug#8171: [dd] bs=blocksize doesn't work as expected Resent-From: =?UTF-8?Q?=D0=A1=D1=82=D0=B0=D0=BD=D0=B8=D1=81=D0=BB=D0=B0=D0=B2?= Original-Sender: debbugs-submit-bounces@debbugs.gnu.org Resent-To: owner@debbugs.gnu.org Resent-CC: bug-coreutils@gnu.org Resent-Date: Fri, 04 Mar 2011 05:07:02 +0000 Resent-Message-ID: Resent-Sender: help-debbugs@gnu.org X-GNU-PR-Message: report 8171 X-GNU-PR-Package: coreutils X-GNU-PR-Keywords: To: 8171@debbugs.gnu.org X-Debbugs-Original-To: bug-coreutils@gnu.org Received: via spool by submit@debbugs.gnu.org id=B.129921517327603 (code B ref -1); Fri, 04 Mar 2011 05:07:02 +0000 Received: (at submit) by debbugs.gnu.org; 4 Mar 2011 05:06:13 +0000 Received: from localhost ([127.0.0.1] helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.69) (envelope-from ) id 1PvNDQ-0007BA-6j for submit@debbugs.gnu.org; Fri, 04 Mar 2011 00:06:12 -0500 Received: from eggs.gnu.org ([140.186.70.92]) by debbugs.gnu.org with esmtp (Exim 4.69) (envelope-from ) id 1PvNAS-000762-0k for submit@debbugs.gnu.org; Fri, 04 Mar 2011 00:03:08 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1PvNAL-0007L4-QA for submit@debbugs.gnu.org; Fri, 04 Mar 2011 00:03:02 -0500 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on eggs.gnu.org X-Spam-Level: X-Spam-Status: No, score=-2.6 required=5.0 tests=BAYES_00,FREEMAIL_FROM, HTML_MESSAGE,RCVD_IN_DNSWL_LOW,T_DKIM_INVALID,T_TO_NO_BRKTS_FREEMAIL autolearn=unavailable version=3.3.1 Received: from lists.gnu.org ([199.232.76.165]:35831) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1PvNAL-0007Kx-Na for submit@debbugs.gnu.org; Fri, 04 Mar 2011 00:03:01 -0500 Received: from [140.186.70.92] (port=34308 helo=eggs.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1PvNAJ-0001Qe-Ox for bug-coreutils@gnu.org; Fri, 04 Mar 2011 00:03:01 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1PvNAH-0007K9-SH for bug-coreutils@gnu.org; Fri, 04 Mar 2011 00:02:59 -0500 Received: from mail-iy0-f169.google.com ([209.85.210.169]:53499) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1PvNAH-0007K2-OZ for bug-coreutils@gnu.org; Fri, 04 Mar 2011 00:02:57 -0500 Received: by iyf13 with SMTP id 13so2144231iyf.0 for ; Thu, 03 Mar 2011 21:02:56 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:mime-version:date:message-id:subject:from:to :content-type; bh=G3YeNPuSRpcLwOL9c90MHAhq7qIt7kVaNmqxxkeeuAs=; b=HqC8nxwZIiIUJ3epfUaWY8h5YUxhenFW2Qsso+qrRF1DKo/Ow94u5RiozCJhxYDAFA 0wSWzP9lLciQMwzQdOA9KaHd/Y7LuZv6AmRj+kgZLKDHdxVC0hGXE8l+Dnp+gb0nsrhl C4cet/78Ca+jgE0E0ZRfZbdnK8ZdAOApht5Js= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:date:message-id:subject:from:to:content-type; b=jjVofJHoyvgreOc9DJsUlefa5ORWR5WzN5c2AOa38wxKzx0SIv1tTWa/sjowrFsG9R ANWqd5T5gwdA599rtEfUc0mK8E5Fq40e+6zryRrE19o7VvwGR8hlCPCboa59uyzIFniH iYTA3/vpCelJcH8JKdgc/7PenjtsCPacBtZHI= MIME-Version: 1.0 Received: by 10.42.173.70 with SMTP id q6mr19029icz.460.1299214976446; Thu, 03 Mar 2011 21:02:56 -0800 (PST) Received: by 10.42.173.129 with HTTP; Thu, 3 Mar 2011 21:02:56 -0800 (PST) Date: Fri, 4 Mar 2011 08:02:56 +0300 Message-ID: From: =?UTF-8?Q?=D0=A1=D1=82=D0=B0=D0=BD=D0=B8=D1=81=D0=BB=D0=B0=D0=B2?= Content-Type: multipart/alternative; boundary=90e6ba6e8cdc287285049da10fa4 X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.6 (newer, 2) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.6 (newer, 2) X-Received-From: 199.232.76.165 X-Spam-Score: -5.9 (-----) X-Mailman-Approved-At: Fri, 04 Mar 2011 00:06:11 -0500 X-BeenThere: debbugs-submit@debbugs.gnu.org X-Mailman-Version: 2.1.11 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: debbugs-submit-bounces@debbugs.gnu.org Errors-To: debbugs-submit-bounces@debbugs.gnu.org X-Spam-Score: -5.9 (-----) --90e6ba6e8cdc287285049da10fa4 Content-Type: text/plain; charset=UTF-8 [dd] bs=blocksize doesn't work as expected, for example: tar -c /somedir | dd bs=256K of=/dev/nst0 In this example backup record will be recorded to a tape with block size = 10K instead of 256K because 10K is default for tar. There is workaround: tar -c /somedir | dd ibs=256K obs=256K of=/dev/nst0 If we set block size for input and output separatly - it works as expected. lucid (utils): The GNU core utilities 7.4-2ubuntu2: amd64 i386 --90e6ba6e8cdc287285049da10fa4 Content-Type: text/html; charset=UTF-8 [dd] bs=blocksize doesn't work as expected, for example:
tar -c /somedir | dd bs=256K of=/dev/nst0
In this example backup record will be recorded to a tape with block size = 10K instead of 256K because 10K is default for tar.
There is workaround:
tar -c /somedir | dd ibs=256K obs=256K of=/dev/nst0
If we set block size for input and output separatly - it works as expected.

lucid (utils): The GNU core utilities
7.4-2ubuntu2: amd64 i386
--90e6ba6e8cdc287285049da10fa4-- From unknown Mon Aug 18 23:56:45 2025 X-Loop: help-debbugs@gnu.org Subject: bug#8171: [dd] bs=blocksize doesn't work as expected Resent-From: Ondrej Vasik Original-Sender: debbugs-submit-bounces@debbugs.gnu.org Resent-To: owner@debbugs.gnu.org Resent-CC: bug-coreutils@gnu.org Resent-Date: Fri, 04 Mar 2011 13:31:02 +0000 Resent-Message-ID: Resent-Sender: help-debbugs@gnu.org X-GNU-PR-Message: followup 8171 X-GNU-PR-Package: coreutils X-GNU-PR-Keywords: To: =?UTF-8?Q?=D0=A1=D1=82=D0=B0=D0=BD=D0=B8=D1=81=D0=BB=D0=B0=D0=B2?= Cc: 8171@debbugs.gnu.org Reply-To: ovasik@redhat.com Received: via spool by 8171-submit@debbugs.gnu.org id=B8171.129924545011237 (code B ref 8171); Fri, 04 Mar 2011 13:31:02 +0000 Received: (at 8171) by debbugs.gnu.org; 4 Mar 2011 13:30:50 +0000 Received: from localhost ([127.0.0.1] helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.69) (envelope-from ) id 1PvV5l-0002vC-MO for submit@debbugs.gnu.org; Fri, 04 Mar 2011 08:30:50 -0500 Received: from mx1.redhat.com ([209.132.183.28]) by debbugs.gnu.org with esmtp (Exim 4.69) (envelope-from ) id 1PvV5j-0002uz-6v for 8171@debbugs.gnu.org; Fri, 04 Mar 2011 08:30:48 -0500 Received: from int-mx10.intmail.prod.int.phx2.redhat.com (int-mx10.intmail.prod.int.phx2.redhat.com [10.5.11.23]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id p24DUeQ4031122 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK); Fri, 4 Mar 2011 08:30:41 -0500 Received: from [10.34.24.196] (dhcp-24-196.brq.redhat.com [10.34.24.196]) by int-mx10.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id p24DUdfv022788; Fri, 4 Mar 2011 08:30:39 -0500 From: Ondrej Vasik In-Reply-To: References: Content-Type: text/plain; charset="UTF-8" Organization: Red Hat, Inc. Date: Fri, 04 Mar 2011 14:30:38 +0100 Message-ID: <1299245438.3033.52.camel@dhcp-24-196.brq.redhat.com> Mime-Version: 1.0 X-Scanned-By: MIMEDefang 2.68 on 10.5.11.23 Content-Transfer-Encoding: quoted-printable X-MIME-Autoconverted: from 8bit to quoted-printable by mx1.redhat.com id p24DUeQ4031122 X-Spam-Score: -9.7 (---------) X-BeenThere: debbugs-submit@debbugs.gnu.org X-Mailman-Version: 2.1.11 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: debbugs-submit-bounces@debbugs.gnu.org Errors-To: debbugs-submit-bounces@debbugs.gnu.org X-Spam-Score: -9.8 (---------) On Fri, 2011-03-04 at 08:02 +0300, =D0=A1=D1=82=D0=B0=D0=BD=D0=B8=D1=81=D0= =BB=D0=B0=D0=B2 wrote: > [dd] bs=3Dblocksize doesn't work as expected, for example: > tar -c /somedir | dd bs=3D256K of=3D/dev/nst0 > In this example backup record will be recorded to a tape with block siz= e =3D > 10K instead of 256K because 10K is default for tar. > There is workaround: > tar -c /somedir | dd ibs=3D256K obs=3D256K of=3D/dev/nst0 > If we set block size for input and output separatly - it works as expec= ted. Even partial block (short read) is a block - especially when you read via pipe. If you want to have only fullblock, dd provides iflag=3Dfullblock for you. See info documentation (or online GNU coreutil= s manual) for details. > lucid (utils): The GNU cor= e > utilities > 7.4-2ubuntu2: amd64 i386 Current version is 8.10, but iflag=3Dfullblock should be present there - added in 7.0 From unknown Mon Aug 18 23:56:45 2025 MIME-Version: 1.0 X-Mailer: MIME-tools 5.427 (Entity 5.427) X-Loop: help-debbugs@gnu.org From: help-debbugs@gnu.org (GNU bug Tracking System) To: =?UTF-8?Q?=D0=A1=D1=82=D0=B0=D0=BD=D0=B8=D1=81=D0=BB=D0=B0=D0=B2?= Subject: bug#8171: closed (Re: bug#8171: [dd] bs=blocksize doesn't work as expected) Message-ID: References: <4D70F0FB.1030102@draigBrady.com> X-Gnu-PR-Message: they-closed 8171 X-Gnu-PR-Package: coreutils Reply-To: 8171@debbugs.gnu.org Date: Fri, 04 Mar 2011 14:04:01 +0000 Content-Type: multipart/mixed; boundary="----------=_1299247441-14017-1" This is a multi-part message in MIME format... ------------=_1299247441-14017-1 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Your bug report #8171: [dd] bs=3Dblocksize doesn't work as expected which was filed against the coreutils package, has been closed. The explanation is attached below, along with your original report. If you require more details, please reply to 8171@debbugs.gnu.org. --=20 8171: http://debbugs.gnu.org/cgi/bugreport.cgi?bug=3D8171 GNU Bug Tracking System Contact help-debbugs@gnu.org with problems ------------=_1299247441-14017-1 Content-Type: message/rfc822 Content-Disposition: inline Content-Transfer-Encoding: 7bit Received: (at 8171-done) by debbugs.gnu.org; 4 Mar 2011 14:03:28 +0000 Received: from localhost ([127.0.0.1] helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.69) (envelope-from ) id 1PvVbL-0003dJ-CG for submit@debbugs.gnu.org; Fri, 04 Mar 2011 09:03:27 -0500 Received: from mail1.slb.deg.dub.stisp.net ([84.203.253.98]) by debbugs.gnu.org with smtp (Exim 4.69) (envelope-from ) id 1PvVbJ-0003d7-M8 for 8171-done@debbugs.gnu.org; Fri, 04 Mar 2011 09:03:26 -0500 Received: (qmail 74279 invoked from network); 4 Mar 2011 14:03:19 -0000 Received: from unknown (HELO ?192.168.2.25?) (84.203.137.218) by mail1.slb.deg.dub.stisp.net with SMTP; 4 Mar 2011 14:03:19 -0000 Message-ID: <4D70F0FB.1030102@draigBrady.com> Date: Fri, 04 Mar 2011 14:02:35 +0000 From: =?UTF-8?B?UMOhZHJhaWcgQnJhZHk=?= User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9.1.8) Gecko/20100227 Thunderbird/3.0.3 MIME-Version: 1.0 To: =?UTF-8?B?0KHRgtCw0L3QuNGB0LvQsNCy?= Subject: Re: bug#8171: [dd] bs=blocksize doesn't work as expected References: In-Reply-To: X-Enigmail-Version: 1.0.1 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-Spam-Score: -2.7 (--) X-Debbugs-Envelope-To: 8171-done Cc: 8171-done@debbugs.gnu.org X-BeenThere: debbugs-submit@debbugs.gnu.org X-Mailman-Version: 2.1.11 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: debbugs-submit-bounces@debbugs.gnu.org Errors-To: debbugs-submit-bounces@debbugs.gnu.org X-Spam-Score: -2.7 (--) On 04/03/11 05:02, Станислав wrote: > [dd] bs=blocksize doesn't work as expected, for example: > tar -c /somedir | dd bs=256K of=/dev/nst0 > In this example backup record will be recorded to a tape with block size = > 10K instead of 256K because 10K is default for tar. > There is workaround: > tar -c /somedir | dd ibs=256K obs=256K of=/dev/nst0 > If we set block size for input and output separatly - it works as expected. This operation is expected and dictated by POSIX. It is surprising though, and I tried to clarify it in the docs: http://git.sv.gnu.org/gitweb/?p=coreutils.git;a=commitdiff;h=d5ab0599 Note also that we're currently considering warning that iflag=fullblock should be used, but only currently in the case were a count is specified, as then you get the wrong amount of data as well as the wrong sized writes. http://debbugs.gnu.org/cgi/bugreport.cgi?bug=7362 cheers, Pádraig. ------------=_1299247441-14017-1 Content-Type: message/rfc822 Content-Disposition: inline Content-Transfer-Encoding: 7bit Received: (at submit) by debbugs.gnu.org; 4 Mar 2011 05:06:13 +0000 Received: from localhost ([127.0.0.1] helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.69) (envelope-from ) id 1PvNDQ-0007BA-6j for submit@debbugs.gnu.org; Fri, 04 Mar 2011 00:06:12 -0500 Received: from eggs.gnu.org ([140.186.70.92]) by debbugs.gnu.org with esmtp (Exim 4.69) (envelope-from ) id 1PvNAS-000762-0k for submit@debbugs.gnu.org; Fri, 04 Mar 2011 00:03:08 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1PvNAL-0007L4-QA for submit@debbugs.gnu.org; Fri, 04 Mar 2011 00:03:02 -0500 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on eggs.gnu.org X-Spam-Level: X-Spam-Status: No, score=-2.6 required=5.0 tests=BAYES_00,FREEMAIL_FROM, HTML_MESSAGE,RCVD_IN_DNSWL_LOW,T_DKIM_INVALID,T_TO_NO_BRKTS_FREEMAIL autolearn=unavailable version=3.3.1 Received: from lists.gnu.org ([199.232.76.165]:35831) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1PvNAL-0007Kx-Na for submit@debbugs.gnu.org; Fri, 04 Mar 2011 00:03:01 -0500 Received: from [140.186.70.92] (port=34308 helo=eggs.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1PvNAJ-0001Qe-Ox for bug-coreutils@gnu.org; Fri, 04 Mar 2011 00:03:01 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1PvNAH-0007K9-SH for bug-coreutils@gnu.org; Fri, 04 Mar 2011 00:02:59 -0500 Received: from mail-iy0-f169.google.com ([209.85.210.169]:53499) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1PvNAH-0007K2-OZ for bug-coreutils@gnu.org; Fri, 04 Mar 2011 00:02:57 -0500 Received: by iyf13 with SMTP id 13so2144231iyf.0 for ; Thu, 03 Mar 2011 21:02:56 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:mime-version:date:message-id:subject:from:to :content-type; bh=G3YeNPuSRpcLwOL9c90MHAhq7qIt7kVaNmqxxkeeuAs=; b=HqC8nxwZIiIUJ3epfUaWY8h5YUxhenFW2Qsso+qrRF1DKo/Ow94u5RiozCJhxYDAFA 0wSWzP9lLciQMwzQdOA9KaHd/Y7LuZv6AmRj+kgZLKDHdxVC0hGXE8l+Dnp+gb0nsrhl C4cet/78Ca+jgE0E0ZRfZbdnK8ZdAOApht5Js= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:date:message-id:subject:from:to:content-type; b=jjVofJHoyvgreOc9DJsUlefa5ORWR5WzN5c2AOa38wxKzx0SIv1tTWa/sjowrFsG9R ANWqd5T5gwdA599rtEfUc0mK8E5Fq40e+6zryRrE19o7VvwGR8hlCPCboa59uyzIFniH iYTA3/vpCelJcH8JKdgc/7PenjtsCPacBtZHI= MIME-Version: 1.0 Received: by 10.42.173.70 with SMTP id q6mr19029icz.460.1299214976446; Thu, 03 Mar 2011 21:02:56 -0800 (PST) Received: by 10.42.173.129 with HTTP; Thu, 3 Mar 2011 21:02:56 -0800 (PST) Date: Fri, 4 Mar 2011 08:02:56 +0300 Message-ID: Subject: [dd] bs=blocksize doesn't work as expected From: =?UTF-8?B?0KHRgtCw0L3QuNGB0LvQsNCy?= To: bug-coreutils@gnu.org Content-Type: multipart/alternative; boundary=90e6ba6e8cdc287285049da10fa4 X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.6 (newer, 2) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.6 (newer, 2) X-Received-From: 199.232.76.165 X-Spam-Score: -5.9 (-----) X-Debbugs-Envelope-To: submit X-Mailman-Approved-At: Fri, 04 Mar 2011 00:06:11 -0500 X-BeenThere: debbugs-submit@debbugs.gnu.org X-Mailman-Version: 2.1.11 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: debbugs-submit-bounces@debbugs.gnu.org Errors-To: debbugs-submit-bounces@debbugs.gnu.org X-Spam-Score: -5.9 (-----) --90e6ba6e8cdc287285049da10fa4 Content-Type: text/plain; charset=UTF-8 [dd] bs=blocksize doesn't work as expected, for example: tar -c /somedir | dd bs=256K of=/dev/nst0 In this example backup record will be recorded to a tape with block size = 10K instead of 256K because 10K is default for tar. There is workaround: tar -c /somedir | dd ibs=256K obs=256K of=/dev/nst0 If we set block size for input and output separatly - it works as expected. lucid (utils): The GNU core utilities 7.4-2ubuntu2: amd64 i386 --90e6ba6e8cdc287285049da10fa4 Content-Type: text/html; charset=UTF-8 [dd] bs=blocksize doesn't work as expected, for example:
tar -c /somedir | dd bs=256K of=/dev/nst0
In this example backup record will be recorded to a tape with block size = 10K instead of 256K because 10K is default for tar.
There is workaround:
tar -c /somedir | dd ibs=256K obs=256K of=/dev/nst0
If we set block size for input and output separatly - it works as expected.

lucid (utils): The GNU core utilities
7.4-2ubuntu2: amd64 i386
--90e6ba6e8cdc287285049da10fa4-- ------------=_1299247441-14017-1-- From unknown Mon Aug 18 23:56:45 2025 X-Loop: help-debbugs@gnu.org Subject: bug#8171: References: In-Reply-To: Resent-From: =?UTF-8?Q?=D0=A1=D1=82=D0=B0=D0=BD=D0=B8=D1=81=D0=BB=D0=B0=D0=B2?= Original-Sender: debbugs-submit-bounces@debbugs.gnu.org Resent-To: owner@debbugs.gnu.org Resent-CC: bug-coreutils@gnu.org Resent-Date: Fri, 04 Mar 2011 15:28:01 +0000 Resent-Message-ID: Resent-Sender: help-debbugs@gnu.org X-GNU-PR-Message: followup 8171 X-GNU-PR-Package: coreutils X-GNU-PR-Keywords: To: 8171@debbugs.gnu.org Received: via spool by 8171-submit@debbugs.gnu.org id=B8171.129925246621462 (code B ref 8171); Fri, 04 Mar 2011 15:28:01 +0000 Received: (at 8171) by debbugs.gnu.org; 4 Mar 2011 15:27:46 +0000 Received: from localhost ([127.0.0.1] helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.69) (envelope-from ) id 1PvWuw-0005a7-CU for submit@debbugs.gnu.org; Fri, 04 Mar 2011 10:27:46 -0500 Received: from mail-iw0-f172.google.com ([209.85.214.172]) by debbugs.gnu.org with esmtp (Exim 4.69) (envelope-from ) id 1PvWuu-0005Zv-0j for 8171@debbugs.gnu.org; Fri, 04 Mar 2011 10:27:44 -0500 Received: by iwl42 with SMTP id 42so1955467iwl.3 for <8171@debbugs.gnu.org>; Fri, 04 Mar 2011 07:27:38 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:mime-version:date:message-id:subject:from:to :content-type; bh=9IVzpNRVgDXK3UMyzFvPyov163lBopxhmXMiG0ZwJAM=; b=EKm2O2d4spZEDoGqSD5wMbF4sWuIRvH0F9UUBiuz1+cfI6sw0Gm0e3YxlG28pgOWks CZ5K4Y2pwp1TwveyNqoe9lqoovHhNz6+fDa9bxgZBKmoySccYbEO0pK9XjbVAxWKSwOl TDnfVY6CnfgLxfrvUosz8YTV2dPRPcgxnMPMM= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:date:message-id:subject:from:to:content-type; b=v7CIY3iifCLITuKHewkudlaO1KjOa5W1IzUVNZrjvwOq36757KIdHHO1n6uTmgV7CC idUgT2uNu3vczBlugvpqKe4beylvMxoWdvWX2H+9EqEtrkH2xnrafZtr4Bv2rVxcASMJ B+RvGt9NJklWnmz6OcBSCKnLVGKvTwgmx3XqU= MIME-Version: 1.0 Received: by 10.43.62.129 with SMTP id xa1mr141764icb.460.1299252458327; Fri, 04 Mar 2011 07:27:38 -0800 (PST) Received: by 10.42.173.129 with HTTP; Fri, 4 Mar 2011 07:27:38 -0800 (PST) Date: Fri, 4 Mar 2011 18:27:38 +0300 Message-ID: From: =?UTF-8?Q?=D0=A1=D1=82=D0=B0=D0=BD=D0=B8=D1=81=D0=BB=D0=B0=D0=B2?= Content-Type: multipart/alternative; boundary=bcaec51a8362408fd9049da9c91a X-Spam-Score: -2.4 (--) X-BeenThere: debbugs-submit@debbugs.gnu.org X-Mailman-Version: 2.1.11 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: debbugs-submit-bounces@debbugs.gnu.org Errors-To: debbugs-submit-bounces@debbugs.gnu.org X-Spam-Score: -1.2 (-) --bcaec51a8362408fd9049da9c91a Content-Type: text/plain; charset=UTF-8 Thanks a lot for clarifying! I also think it would be nice to notice this behaviour clearer in documentation. man dd says almost nothing about. info dd says about 'short reads' but it seems not so easy to understand what it means. 'dd' is populary utility in scripts so many people can bumb into this behaviour. As for me it took two months to catch 'slow' problem with our tape drive. PS: Is it good work around that I mentioned before (I mean 'ibs=256K obs=256K') or it can be changed in future? Best regards, Stanislav --bcaec51a8362408fd9049da9c91a Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Thanks a lot for clarifying!

I also think it would be nice to notice= this behaviour clearer in documentation. man dd says almost nothing about.= info dd says about 'short reads' but it seems not so easy to under= stand what it means. 'dd' is populary utility in scripts so many pe= ople can bumb into this behaviour. As for me it took two months to catch &#= 39;slow' problem with our tape drive.

PS: Is it good work around that I mentioned before (I mean 'ibs=3D2= 56K obs=3D256K') or it can be changed in future?

Best regards,Stanislav
--bcaec51a8362408fd9049da9c91a-- From unknown Mon Aug 18 23:56:45 2025 X-Loop: help-debbugs@gnu.org Subject: bug#8171: Resent-From: Eric Blake Original-Sender: debbugs-submit-bounces@debbugs.gnu.org Resent-To: owner@debbugs.gnu.org Resent-CC: bug-coreutils@gnu.org Resent-Date: Fri, 04 Mar 2011 15:42:01 +0000 Resent-Message-ID: Resent-Sender: help-debbugs@gnu.org X-GNU-PR-Message: followup 8171 X-GNU-PR-Package: coreutils X-GNU-PR-Keywords: To: =?UTF-8?Q?=D0=A1=D1=82=D0=B0=D0=BD=D0=B8=D1=81=D0=BB=D0=B0=D0=B2?= Cc: 8171@debbugs.gnu.org Received: via spool by 8171-submit@debbugs.gnu.org id=B8171.129925330922662 (code B ref 8171); Fri, 04 Mar 2011 15:42:01 +0000 Received: (at 8171) by debbugs.gnu.org; 4 Mar 2011 15:41:49 +0000 Received: from localhost ([127.0.0.1] helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.69) (envelope-from ) id 1PvX8W-0005tT-VE for submit@debbugs.gnu.org; Fri, 04 Mar 2011 10:41:49 -0500 Received: from mx1.redhat.com ([209.132.183.28]) by debbugs.gnu.org with esmtp (Exim 4.69) (envelope-from ) id 1PvX8U-0005tG-Om for 8171@debbugs.gnu.org; Fri, 04 Mar 2011 10:41:47 -0500 Received: from int-mx01.intmail.prod.int.phx2.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id p24FffIl005930 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK); Fri, 4 Mar 2011 10:41:41 -0500 Received: from [10.3.113.122] (ovpn-113-122.phx2.redhat.com [10.3.113.122]) by int-mx01.intmail.prod.int.phx2.redhat.com (8.13.8/8.13.8) with ESMTP id p24FfejT013254; Fri, 4 Mar 2011 10:41:40 -0500 Message-ID: <4D710834.7070005@redhat.com> Date: Fri, 04 Mar 2011 08:41:40 -0700 From: Eric Blake Organization: Red Hat User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.2.13) Gecko/20101209 Fedora/3.1.7-0.35.b3pre.fc14 Lightning/1.0b3pre Mnenhy/0.8.3 Thunderbird/3.1.7 MIME-Version: 1.0 References: In-Reply-To: X-Enigmail-Version: 1.1.2 OpenPGP: url=http://people.redhat.com/eblake/eblake.gpg Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="------------enigA922B600F8BE3EA32C703932" X-Scanned-By: MIMEDefang 2.67 on 10.5.11.11 X-Spam-Score: -10.3 (----------) X-BeenThere: debbugs-submit@debbugs.gnu.org X-Mailman-Version: 2.1.11 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: debbugs-submit-bounces@debbugs.gnu.org Errors-To: debbugs-submit-bounces@debbugs.gnu.org X-Spam-Score: -10.3 (----------) This is an OpenPGP/MIME signed message (RFC 2440 and 3156) --------------enigA922B600F8BE3EA32C703932 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable On 03/04/2011 08:27 AM, =D0=A1=D1=82=D0=B0=D0=BD=D0=B8=D1=81=D0=BB=D0=B0=D0= =B2 wrote: > Thanks a lot for clarifying! >=20 > I also think it would be nice to notice this behaviour clearer in > documentation. man dd says almost nothing about. info dd says about 'sh= ort > reads' but it seems not so easy to understand what it means. 'dd' is > populary utility in scripts so many people can bumb into this behaviour= =2E As > for me it took two months to catch 'slow' problem with our tape drive. >=20 > PS: Is it good work around that I mentioned before (I mean 'ibs=3D256K > obs=3D256K') or it can be changed in future? POSIX requires that 'ibs=3Dn obs=3Dn' behave the way you want; it is _onl= y_ the 'bs=3Dn' behavior where a short read results in surprising behavior. --=20 Eric Blake eblake@redhat.com +1-801-349-2682 Libvirt virtualization library http://libvirt.org --------------enigA922B600F8BE3EA32C703932 Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.11 (GNU/Linux) Comment: Public key at http://people.redhat.com/eblake/eblake.gpg Comment: Using GnuPG with Fedora - http://enigmail.mozdev.org/ iQEcBAEBCAAGBQJNcQg0AAoJEKeha0olJ0NqauEH/2uqgkrs/TZXbtCbPZyVVB3Q RyVz6xCGA+FgtPm793GnzzpzFMU8Wr0O6bTxYyxC+hFQ1MMkTn++LKCaMwX1he0z amR0926FXTik6RzJTQzlvMpRF14hhVpoMSe0D+MLz4UH9ebMckv10KNnnQ20eAlf piiaAUrtw8fiviVfpQ5Bxn2J1MbxANbdrLcTQgiO0m+5sos1K2hEoNB26IQwvHue VioCW+cdSD4Xi8UTvwRMMn3hUlGXg7douu24AD23MtuaKGpGjwvgD9hRg9kWbe6M oU+KH8PogBzXQrrvOeJqoC+dvufrZQIVIH6Ey6yj3i2NdQmyrDAnuJyx4VM8Acw= =z9y0 -----END PGP SIGNATURE----- --------------enigA922B600F8BE3EA32C703932-- From unknown Mon Aug 18 23:56:45 2025 X-Loop: help-debbugs@gnu.org Subject: bug#8171: Resent-From: =?UTF-8?Q?P=C3=A1draig?= Brady Original-Sender: debbugs-submit-bounces@debbugs.gnu.org Resent-To: owner@debbugs.gnu.org Resent-CC: bug-coreutils@gnu.org Resent-Date: Fri, 04 Mar 2011 15:46:01 +0000 Resent-Message-ID: Resent-Sender: help-debbugs@gnu.org X-GNU-PR-Message: followup 8171 X-GNU-PR-Package: coreutils X-GNU-PR-Keywords: To: =?UTF-8?Q?=D0=A1=D1=82=D0=B0=D0=BD=D0=B8=D1=81=D0=BB=D0=B0=D0=B2?= Cc: 8171@debbugs.gnu.org Received: via spool by 8171-submit@debbugs.gnu.org id=B8171.129925355723032 (code B ref 8171); Fri, 04 Mar 2011 15:46:01 +0000 Received: (at 8171) by debbugs.gnu.org; 4 Mar 2011 15:45:57 +0000 Received: from localhost ([127.0.0.1] helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.69) (envelope-from ) id 1PvXCX-0005zR-6M for submit@debbugs.gnu.org; Fri, 04 Mar 2011 10:45:57 -0500 Received: from mail1.slb.deg.dub.stisp.net ([84.203.253.98]) by debbugs.gnu.org with smtp (Exim 4.69) (envelope-from ) id 1PvXCU-0005zC-U0 for 8171@debbugs.gnu.org; Fri, 04 Mar 2011 10:45:55 -0500 Received: (qmail 94083 invoked from network); 4 Mar 2011 15:45:48 -0000 Received: from unknown (HELO ?192.168.2.25?) (84.203.137.218) by mail1.slb.deg.dub.stisp.net with SMTP; 4 Mar 2011 15:45:48 -0000 Message-ID: <4D710900.4050503@draigBrady.com> Date: Fri, 04 Mar 2011 15:45:04 +0000 From: =?UTF-8?Q?P=C3=A1draig?= Brady User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9.1.8) Gecko/20100227 Thunderbird/3.0.3 MIME-Version: 1.0 References: In-Reply-To: X-Enigmail-Version: 1.0.1 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-Spam-Score: -2.7 (--) X-BeenThere: debbugs-submit@debbugs.gnu.org X-Mailman-Version: 2.1.11 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: debbugs-submit-bounces@debbugs.gnu.org Errors-To: debbugs-submit-bounces@debbugs.gnu.org X-Spam-Score: -2.7 (--) On 04/03/11 15:27, Станислав wrote: > Thanks a lot for clarifying! > > I also think it would be nice to notice this behaviour clearer in > documentation. man dd says almost nothing about. info dd says about 'short > reads' but it seems not so easy to understand what it means. 'dd' is > populary utility in scripts so many people can bumb into this behaviour. As > for me it took two months to catch 'slow' problem with our tape drive. I'll think about improving the man page, maybe by doing: - bs=BYTES read and write BYTES bytes at a time (also see ibs=,obs=) + bs=BYTES read and write up to BYTES bytes at a time - ibs=BYTES read BYTES bytes at a time (default: 512) - ibs=BYTES read up to BYTES bytes at a time (default: 512) > PS: Is it good work around that I mentioned before (I mean 'ibs=256K > obs=256K') or it can be changed in future? That behavior will not change and is a valid workaround, that works on all flavors of dd cheers, Pádraig. From unknown Mon Aug 18 23:56:45 2025 X-Loop: help-debbugs@gnu.org Subject: bug#8171: References: In-Reply-To: Resent-From: =?UTF-8?Q?=D0=A1=D1=82=D0=B0=D0=BD=D0=B8=D1=81=D0=BB=D0=B0=D0=B2?= Original-Sender: debbugs-submit-bounces@debbugs.gnu.org Resent-To: owner@debbugs.gnu.org Resent-CC: bug-coreutils@gnu.org Resent-Date: Sat, 05 Mar 2011 08:11:01 +0000 Resent-Message-ID: Resent-Sender: help-debbugs@gnu.org X-GNU-PR-Message: followup 8171 X-GNU-PR-Package: coreutils X-GNU-PR-Keywords: To: 8171@debbugs.gnu.org Received: via spool by 8171-submit@debbugs.gnu.org id=B8171.129931265319399 (code B ref 8171); Sat, 05 Mar 2011 08:11:01 +0000 Received: (at 8171) by debbugs.gnu.org; 5 Mar 2011 08:10:53 +0000 Received: from localhost ([127.0.0.1] helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.69) (envelope-from ) id 1PvmZh-00052q-DW for submit@debbugs.gnu.org; Sat, 05 Mar 2011 03:10:53 -0500 Received: from mail-iy0-f172.google.com ([209.85.210.172]) by debbugs.gnu.org with esmtp (Exim 4.69) (envelope-from ) id 1PvmZg-00052f-EX for 8171@debbugs.gnu.org; Sat, 05 Mar 2011 03:10:52 -0500 Received: by iyj8 with SMTP id 8so2483744iyj.3 for <8171@debbugs.gnu.org>; Sat, 05 Mar 2011 00:10:46 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:mime-version:date:message-id:subject:from:to :content-type; bh=xVMWsSnkRPv1xLfFqmTt7QGsOKKATqqAIlSCFjAa9pA=; b=cKLGgGl+cpHXRNAhDl9HxyMEIz/FZlnuJmJ8952LElCwLVNh6ahEvKq63Uf/dmqnXm hNT4wSlTh1p5YKzyOxcZbNRYkYhJ4urX0tWY4M1tizzmlULXvml+rY37bmvrG0ezRVSx K09kDVHalPDHfHs0fO2Jdu5ZOQTJVdISdqWCU= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:date:message-id:subject:from:to:content-type; b=R18Qo3cNzLrZ5HeuqkpRqBdIbkWaKmdDfR3kcaVNAxxGrZghY9do9lkSxloET5kzUk vzOEYZx7Wrtl0DFQrPKW5cSvFcCoR3KutwHQtoah+2zvAlxBozh2ZJsyyXCA/Ew6eW3Z +0AGvc/lzzaq88Yi2ZYYHYYrElOt5fY9z1uko= MIME-Version: 1.0 Received: by 10.43.50.199 with SMTP id vf7mr1879333icb.125.1299312646779; Sat, 05 Mar 2011 00:10:46 -0800 (PST) Received: by 10.42.173.129 with HTTP; Sat, 5 Mar 2011 00:10:46 -0800 (PST) Date: Sat, 5 Mar 2011 11:10:46 +0300 Message-ID: From: =?UTF-8?Q?=D0=A1=D1=82=D0=B0=D0=BD=D0=B8=D1=81=D0=BB=D0=B0=D0=B2?= Content-Type: multipart/alternative; boundary=bcaec5299ec5c3717e049db7ccfa X-Spam-Score: -0.6 (/) X-BeenThere: debbugs-submit@debbugs.gnu.org X-Mailman-Version: 2.1.11 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: debbugs-submit-bounces@debbugs.gnu.org Errors-To: debbugs-submit-bounces@debbugs.gnu.org X-Spam-Score: -0.3 (/) --bcaec5299ec5c3717e049db7ccfa Content-Type: text/plain; charset=UTF-8 Thank you very much! --bcaec5299ec5c3717e049db7ccfa Content-Type: text/html; charset=UTF-8 Thank you very much!
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