On Mon, 15 Mar 2004 16:17, [EMAIL PROTECTED] wrote:
> Hi there,
>
> On Thu, 11 Mar 2004, Rocky Zhang wrote:
> > I connected 4 USB floppy drives into my computer running redhat9. The
> > logical device is /dev/sda, /dev/sdb, /dev/sdc, /dev/sdd. I can see
> > /proc/bus/usb/deivces USB device information(include bus number and
> > port number), but it do not display logical device. How can use
> > command or other ways to find physicl location(Bus number and port
> > number) of /dev/sda?
>
> I think this is a lot easier with 2.6 kernels than with 2.4.
>
> 73,
> Ged.

In 2.6 it's now possible to identify which device has just been plugged
in terms of its numerical SCSI /dev/sg[0123...] device.  But if you're using
traditional /dev/sd[abc...] you still need some way of getting from /dev/sgN
to /dev/sdX.   For those not familiar with the problem: the sequence 
allocated in the /dev/sg[0123...] doesn't necessarily stay in alignment 
with the sequence allocated being allocated with /dev/sd[abc...] - so 
given /dev/sgN there's no simple way to figure out what /dev/sdX should be.  

I replied to this before - but I was having a bad day and stuffed
up the posting.  It was a short posting so I'll repeat it here:

As far as I can tell, the only way to do this is to use sg_map from sg3_utils 
( http://www.torque.net/sg/u_index.html ).  I use it in my own usb desktop 
integration scripts, see http://users.actrix.co.nz/michael/usbmount.html
Basically in bash:

function scsiDevFromHostNumber {
    local n=$1
    local scsiDiskDev=`sg_map -sd -a -x | awk --assign n=$n '$2 == n && NF == 7 { 
print $7 }'`
    if [ -z "$scsiDiskDev" ]; then
        scsiDiskDev="UNKNOWN"
    fi
    echo $scsiDiskDev
}



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