Abstract: The apparent speed of a connection between a browser at a user station and a proxy or gateway on a network such as the Internet is increased by providing a local proxy at the user station which interacts with a remote proxy. While the remote proxy is retrieving a newly requested World Wide Web page, for example, from the appropriate content provider, it may also be sending to the local proxy a stale cached version of that page. When the new version of the page is finally retrieved, the remote proxy determines the differences between the new version and the stale version, and, assuming the differences do not exceed the new page in size, sends the differences to the local proxy which then reconstructs the new page from the differences and the stale version. The local proxy delivers the new page to the browser, which need not even be aware that a local proxy exists; it is aware only that it received the page it requested.

Abstract: The invention is directed to an automotive light signal which comprise a housing with at least one electric bulb inside. According to the invention, a portion of light emission from the signal is diverted in such a way that the driver can see the same light that is directed outside the vehicle. Thus, a failure-proof end-to-end check of the operability of the signal is accomplished by the driver without resorting to help of another person. The invention is especially important for brake and backing signals, which currently require the driver to request outside help to perform end-to-end checking.

Abstract: A token-based protocol used to prevent conflicts between copies of the same data items residing in different servers of a replicated distributed system is provided. The servers in the system with database replicas are provided with token pointers that are each associated with a token. Token pointers are used to track the current possessor of the token. Whenever a server receives or transfers a token, its corresponding token pointer is updated to reflect which server possesses the token. The use of token pointers advantageously eliminates the need for global cooperation by the servers to regenerate a lost token.

Abstract: A replication protocol which includes associating a database version vector with each copy of the database in the system is provided. Each database version vector keeps track of the total number of updates to any data items in its respective database replica and from which server those updates were originally performed. During replication between two replicas, the database version vectors of the replicas are compared to efficiently determine if update replication is necessary. If the database version vectors are not identical, the server possessing the more recent version of the data items propagates those data items to the server whose replica is older using conventional update propagation techniques. Identical database version vectors indicate that update propagation is not necessary. As such, the protocol avoids examining every data item in the database in order to determine the necessity of update propagation, which is required in conventional replication protocols.