protected function _determineI5()
    {
        // first us the compiled flag.
        $this->_isI5 = (php_uname('s') == 'OS400') ? true : false;

        // if this is set, then us it
        if (isset($this->_config['os'])){
            if (strtolower($this->_config['os']) === 'i5') {
                $this->_isI5 = true;
            } else {
                // any other value passed in, its null
                $this->_isI5 = false;
            }
        }

    }