public function checkFilesystem()
    {
        $results = array(
            $this->checkPermissions(GC_FILE_CONFIG_COMPILED)
        );

        if (file_exists(GC_FILE_CONFIG_COMPILED_OVERRIDE)) {
            $results[] = $this->checkPermissions(GC_FILE_CONFIG_COMPILED_OVERRIDE);
        }

        $filtered = array_filter($results, 'is_string');
        return empty($filtered) ? true : $filtered;
    }