SUMMARY: Solaris 2.5 tape device numbering

From: Marc S. Gibian (gibian@drizzle)
Date: Fri Aug 16 1996 - 13:34:08 CDT


Tape devices are added in the order they are recognized, starting with
/dev/rmt/0. This is independent of the SCSI target of the drive UNLESS it
affects the recognition order. boot -r does not remove device files for tape
drives no longer present on the system and existing associations between a drive
number and a given SCSI controller/device id are not modified once they are
created.

A few people provided suggestions as to how to get a set of devices in /dev/rmt
that reflect only the actual tape devices on a machine:

Possibly the simplest fix would be to edit
/etc/init.d/devlinks and execute rm -f /dev/rmt/* before
/usr/sbin/tapes is run.

and:

rm /dev/rmt/*; touch /reconfigure; /usr/sbin/reboot

Many thanks to:
js@cctechnol.com (Johnie Stafford)
djohnson@nbserv2.dseg.ti.com (Danny Johnson 0172547)
Tommy Williams <tommy@vumclib.mc.vanderbilt.edu>
Glenn.Satchell@uniq.com.au (Glenn Satchell)
nobroin@esoc.esa.de (Niall O Broin - Gray Wizard)
Robert.Gillespie@waii.com (Robert.Gillespie@waii.com)
rtrzaska@uk.mdis.com (Ray Trzaska)
"Robert Tommaselli" <Robert.Tommaselli@ska.com>
Jacques Samson <samson@CCG.RNCan.gc.ca>
fpardo@mail.tisny.com (Frank Pardo)

Marc S. Gibian
Telos Consulting Services phone: (617) 377-6350
PRISM/TFS email: gibian@stars1.hanscom.af.mil

attached mail follows:


My customer is building a software product that includes various mechanisms to
write and read data from tape. The software uses a file to configure the tape
drive device file to use. Given the customer for this product, it is very
important that this file not have to be manually maintained by the product's
users, so...

HOW does Solaris 2.5 assign tape device numbers?

I thought I had it figured out... the first tape drive encountered by a boot -r
is assigned /dev/rmt/0, the second 1, etc... but then I found machines that have
in the past had tape drives, have none right now, but still have rmt devices. I
also found machines with single drives, but with the device number of
/dev/rmt/1...

So, what is going on here? I am guessing that my original conclusion is correct,
and that the boot -r is just never removing device files. But shouldn't a boot
reconfigure, which is recognizing and configuring for the SCSI devices currently
attached, remove device files for devices that are NOT detected???

TIA,

Marc S. Gibian
Telos Consulting Services phone: (617) 377-6350
PRISM/TFS email: gibian@stars1.hanscom.af.mil



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