static protected function isExecAvailable() {
		if (self::$_execAvailable === null) {
			$disabled = explode(',', ini_get('disable_functions'));
			$disabled = array_map('trim', $disabled);
			
			self::$_execAvailable = ! in_array('exec', $disabled, true);
		}
		
		return self::$_execAvailable;
	}