The wide variety of Internet information systems leads to a number of cases where objects should not be cached. In the absence of a standard for specifying TTLs in objects themselves, the Harvest cache chooses not to cache a number of types of objects. For example, objects that are password protected are not cached. Rather, the cache acts as an application gateway and discards the retrieved object as soon as it has been delivered. The cache similarly discards URL's whose name implies the object is not cacheable (e.g. https://www.xyz.com/cgi-bin/query.cgi). for details about cacheable objects.). It is possible to limit the size of the largest cacheable object, so that a few large FTP objects do not purge ten thousand smaller objects from the cache.