From owner-freebsd-hackers Wed May 22 02:44:11 1996 Return-Path: owner-hackers Received: (from root@localhost) by freefall.freebsd.org (8.7.3/8.7.3) id CAA07703 for hackers-outgoing; Wed, 22 May 1996 02:44:11 -0700 (PDT) Received: from fire.dkrz.de (fire.dkrz.de [136.172.110.250]) by freefall.freebsd.org (8.7.3/8.7.3) with ESMTP id CAA07263 for ; Wed, 22 May 1996 02:40:42 -0700 (PDT) Received: from racer.dkrz.de (racer.dkrz.de [136.172.110.55]) by fire.dkrz.de (8.7.5/8.7.3) with ESMTP id LAA10584 for ; Wed, 22 May 1996 11:40:07 +0200 (MET DST) Received: (from gwk@localhost) by racer.dkrz.de (8.7.4/8.7.3) id LAA01849; Wed, 22 May 1996 11:39:09 +0200 (MET DST) Date: Wed, 22 May 1996 11:39:09 +0200 (MET DST) Message-Id: <199605220939.LAA01849@racer.dkrz.de> From: "Georg-W. Koltermann" To: freebsd-hackers@freebsd.org Subject: 960501-SNAP: data corruption reading /dev/rwt0 (Wangtek) X-Attribution: gwk Reply-to: gwk@cray.com Sender: owner-hackers@freebsd.org X-Loop: FreeBSD.org Precedence: bulk The details are still a bit fuzzy, but maybe someone has seen this already and can give me a hint before I spend countless hours of hunting. Here is what I see: I got an old Wangtek QIC-150 tape device a couple of weeks ago, while still running 2.1.0-RELEASE on my old (386DX/40, 8MB) machine. It seemed to work flawlessly. One week ago I got a new PC (586/100, 32MB, ASUS T2P4), and tried to install 960501-SNAP from tape. Turned out most of the files read from tape were corrupted, so the installation would abort after unpacking one or two files of the first dist. I switched to the shell on VT4 and tried to untar the tape manually, then cat | zcat | cpio -itv to check if I could read the pieces. The tar finished without an error indication, but typically the zcat would abort readily, so I could only list a few files from the archive. I untarred the same tape a couple of times, trying different block sizes on the tar command. Eventually (using a blocking count of 16) I could read the tape without corruption, and could install the snap. Now with the snap loaded and running flawlessly, I want to read my backups from tape (cpio -H crc format), but again I am getting data corruption. When I look at the files extracted, they look fine up to a certain point where they just contain binary zeroes. I have again played with different block sizes for reading the tape, but this time I cannot find a block size that works. Different block sizes do move the point of corruption within the archive, however, so I can be quite sure the tape was written o. k.. Any ideas? Georg