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From: Peter Dufault <dufault@hda.com>
Message-Id: <199607281708.NAA01613@hda.com>
Subject: Re: Setting disk sector size?
To: grog@freefall.freebsd.org (Greg Lehey)
Date: Sun, 28 Jul 1996 13:08:46 -0400 (EDT)
Cc: scsi@freefall.freebsd.org
In-Reply-To: <199607281545.IAA27303@freefall.freebsd.org> from "Greg Lehey" at Jul 28, 96 08:45:13 am
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> 
> Yes, we have this option too (with a Tandem box, of course), and if
> things get too hard I'll do just that.  But I didn't want to give up
> without a fight :-)
> 

See if something like this works.  You'll have to remove the final
"echo".  I haven't tried it - I don't have a disk I'm willing to
change the sector size on right now.

#!/bin/sh

if [ "$#" != "2" ]
	then
	echo "Usage: blocksize ctl-device-name new-block-size"
	exit
fi

CTL=$1
NEWSIZE=$2

# Print out the device we're about to destroy:
scsi -f $CTL -c "12 0 0 0 v 0" 96 -i 96 "s8 z8 z16 z4"

# Read in page 4.  Actually, we only read the block descriptor.
set `scsi -f $CTL \
-c "1A 0 4 0 C 0" \
-i 0xc "{Mode data length} i1 \
{Medium type} i1 \
{Device Specific Parameter} i1 \
{Block descriptor length} i1 \
{Density code} i1 \
{Number of blocks} i3 \
{Reserved} i1 \
{Block length} i3"`

echo "Current block size is: $8"

# Corresponding mode select:

echo scsi -f $CTL -c "15 0 4 0 C 0" \
-o 0xc "i1 i1 i1 i1 i1 i3 i1 i3" $1 $2 $3 $4 $5 $6 $7 $NEWSIZE

-- 
Peter Dufault               Real-Time Machine Control and Simulation
HD Associates, Inc.         Voice: 508 433 6936
dufault@hda.com             Fax:   508 433 5267