librenms-librenms/includes/discovery/os/ibmtl.inc.php

<?php
/*
* LibreNMS
*
* Copyright (c) 2015 Søren Friis Rosiak <sorenrosiak@gmail.com>
* This program is free software: you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the
* Free Software Foundation, either version 3 of the License, or (at your
* option) any later version.  Please see LICENSE.txt at the top level of
* the source code distribution for details.
*/

$ibmtl_snmpget = snmp_get($device, 'SML-MIB::product-Name.0', '-Oqv', '');

if (str_contains($ibmtl_snmpget, 'IBM System Storage TS3500 Tape Library', true)) {
    $os = 'ibmtl';
}