From owner-freebsd-scsi Sat May 25 13:46:10 1996 Return-Path: owner-freebsd-scsi Received: (from root@localhost) by freefall.freebsd.org (8.7.5/8.7.3) id NAA13568 for freebsd-scsi-outgoing; Sat, 25 May 1996 13:46:10 -0700 (PDT) Received: from irz301.inf.tu-dresden.de (irz301.inf.tu-dresden.de [141.76.1.11]) by freefall.freebsd.org (8.7.5/8.7.3) with SMTP id NAA13538; Sat, 25 May 1996 13:45:52 -0700 (PDT) Received: from sax.sax.de by irz301.inf.tu-dresden.de (8.6.12/8.6.12-s1) with ESMTP id WAA14087; Sat, 25 May 1996 22:45:47 +0200 Received: by sax.sax.de (8.6.12/8.6.12-s1) with UUCP id WAA08275; Sat, 25 May 1996 22:45:47 +0200 Received: (from j@localhost) by uriah.heep.sax.de (8.7.5/8.6.9) id WAA27101; Sat, 25 May 1996 22:37:48 +0200 (MET DST) From: J Wunsch Message-Id: <199605252037.WAA27101@uriah.heep.sax.de> Subject: Re: dump and 32blocks limit To: andreas@knobel.gun.de (Andreas Klemm) Date: Sat, 25 May 1996 22:37:47 +0200 (MET DST) Cc: wilko@yedi.iaf.nl, joerg_wunsch@uriah.heep.sax.de, freebsd-scsi@FreeBSD.org, davidg@FreeBSD.org, dyson@FreeBSD.org Reply-To: joerg_wunsch@uriah.heep.sax.de (Joerg Wunsch) In-Reply-To: from Andreas Klemm at "May 25, 96 10:57:17 am" X-Phone: +49-351-2012 669 X-PGP-Fingerprint: DC 47 E6 E4 FF A6 E9 8F 93 21 E0 7D F9 12 D6 4E X-Mailer: ELM [version 2.4ME+ PL17 (25)] MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-freebsd-scsi@FreeBSD.org X-Loop: FreeBSD.org Precedence: bulk As Andreas Klemm wrote: > Well, sometimes I had a SUN 4mm DAT (Archive Python) at home. > When doing backups with dump everything seemed to be fine. I could > choose blocksizes of about 96 blocks (as it's usual on Sun's). Ah! This raises a flag... you've been using 96 KB blocking. Sigh. Now look at the 64 KB physio limitation: your 96 KB has been accepted by dump(8), but physio(9) split it into one 64 KB block (due to its limit), and one 32 KB block. This gives you a tape with alternate 64/32/64/32 KB blocking, nothing you would really like to have... So we should bump the limit to 64 KB, and explain the limitation of physio in the man page (until it's been fixed -- which should remain a goal, think of importing tapes with > 64 KB blocking). -- cheers, J"org joerg_wunsch@uriah.heep.sax.de -- http://www.sax.de/~joerg/ -- NIC: JW11-RIPE Never trust an operating system you don't have sources for. ;-)