From owner-freebsd-scsi  Sun May 26 05:17:04 1996
Return-Path: owner-freebsd-scsi
Received: (from root@localhost)
          by freefall.freebsd.org (8.7.5/8.7.3) id FAA22118
          for freebsd-scsi-outgoing; Sun, 26 May 1996 05:17:04 -0700 (PDT)
Received: from linux4nn.gn.iaf.nl (root@linux4nn.gn.iaf.nl [193.67.144.34])
          by freefall.freebsd.org (8.7.5/8.7.3) with SMTP id FAA22109;
          Sun, 26 May 1996 05:16:58 -0700 (PDT)
Received: from uni4nn.iaf.nl (root@uni4nn.iaf.nl [193.67.144.33]) by linux4nn.gn.iaf.nl (8.6.9/8.6.9) with SMTP id OAA02324; Sun, 26 May 1996 14:17:48 +0200
Received: by uni4nn.iaf.nl with UUCP id AA27331
  (5.67b/IDA-1.5); Sun, 26 May 1996 14:16:27 +0200
Received: by iafnl.es.iaf.nl with UUCP id AA08761
  (5.67b/IDA-1.5); Sun, 26 May 1996 13:41:33 +0200
Received: (from wilko@localhost) by yedi.iaf.nl (8.6.12/8.6.6) id NAA09113; Sun, 26 May 1996 13:15:58 +0200
From: Wilko Bulte <wilko@yedi.iaf.nl>
Message-Id: <199605261115.NAA09113@yedi.iaf.nl>
X-Organisation: Private FreeBSD site - Arnhem - The Netherlands
Subject: Re: dump and 32blocks limit
To: joerg_wunsch@uriah.heep.sax.de
Date: Sun, 26 May 1996 13:15:58 +0200 (MET DST)
Cc: andreas@knobel.gun.de, freebsd-scsi@freebsd.org, davidg@freebsd.org,
        dyson@freebsd.org
In-Reply-To: <199605252037.WAA27101@uriah.heep.sax.de> from "J Wunsch" at May 25, 96 10:37:47 pm
X-Mailer: ELM [version 2.4 PL23]
Mime-Version: 1.0
Content-Type: text/plain; charset=ISO-8859-1
Content-Transfer-Encoding: 7bit
Sender: owner-freebsd-scsi@freebsd.org
X-Loop: FreeBSD.org
Precedence: bulk

As J Wunsch wrote...

> 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...

Ah (again ;-) This is of course in line with my observation of multiple
drive types never being bothered by 64 Kbyte.

> 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).

Yep. Makes my DLT quicker also :)

Wilko
_     __________________________________________________________________________
 |   / o / /  _   Wilko Bulte             email: wilko@yedi.iaf.nl
 |/|/ / / /( (_)  Private FreeBSD site  - Arnhem - The Netherlands
--------------------------------------------------------------------------------