From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Sun, 19 Aug 2001 15:00:00 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Sun, 19 Aug 2001 14:59:50 -0400 Received: from mail.LF.net ([212.9.160.2]:44560 "EHLO mail.LF.net") by vger.kernel.org with ESMTP id ; Sun, 19 Aug 2001 14:59:43 -0400 Message-ID: <3B800CA3.AF9E321F@janglednerves.com> Date: Sun, 19 Aug 2001 20:59:47 +0200 From: Albrecht Jacobs Organization: jangled nerves GmbH X-Mailer: Mozilla 4.51C-SGI [en] (X11; I; IRIX64 6.5 IP30) X-Accept-Language: de, en MIME-Version: 1.0 To: Kai Makisara CC: "(Martin Jacobs)" <100.179370@germanynet.de>, linux-kernel@vger.kernel.org Subject: Re: Q: 2.4.[37]-XFS: /dev/nst0m: cannot allocate memory In-Reply-To: Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Kai Makisara wrote: > > On Fri, 17 Aug 2001, (Martin Jacobs) wrote: > > > Hi all, > > > > I cannot read anything from my tape (Tandberg DLT8000, LVD > > interface, ID=5) connected to an aic7899 or an sym53c895 using > > kernel 2.4.3-XFS or 2.4.7-XFS. (Everything works fine on > > 2.2.16.) Loading of st.o works. stinit works. mt (status, tape > > positioning) works. But when I try to read the amanda header > > from the tape (dd if=/dev/nst0m bs=32k count=1) I get the > > error > > > > dd: reading `/dev/nst0m': Cannot allocate memory > > > ... > > Nearly the same for tar (with default block size of 512 byte). > > > > BUT: if I use bs=64k it works!!? > > > In variable block mode in 2.4, you get ENOMEM if the block on the tape is > larger than the byte count in the read(). 2.2 just returned what you asked > for and silentlry threw away the rest of the block. If the byte count is > larger than the block size, then the block is returned. > > I.e., the first block on your tape is larger than 32 kB. > > Kai If I understand you right this is a FEATURE, not a bug! I find it quite irritating when using a tape device. Shouldn't I get some error message about wrong block size? Forgive me but I am some sort of end user (admin) and not a kernel hacker. BTW, where can I get documentation about this 'feature'? Thanks anyway! -- albrecht jacobs jangled nerves gmbh hallstrasse 25 d-70376 stuttgart fon: +49 711 550375-44 fax: +49 711 550375-22 mailto:albrecht.jacobs@janglednerves.com http://www.janglednerves.com/