protected function _getVirtualizationSystem()
    {
        $sSystemType = '';

        if ($this->isExecAllowed()) {
            //VMWare
            @$sDeviceList = $this->_getDeviceList('vmware');
            if ($sDeviceList) {
                $sSystemType = 'VMWare';
                unset($sDeviceList);
            }

            //VirtualBox
            @$sDeviceList = $this->_getDeviceList('VirtualBox');
            if ($sDeviceList) {
                $sSystemType = 'VirtualBox';
                unset($sDeviceList);
            }
        }

        return $sSystemType;
    }