Abstract: A system for controlling contention between conflicting transactions in a transactional memory system. During operation, the system receives a request to access a cache line and then determines if the cache line is already in use by an existing transaction in a cache state that is incompatible with the request. If so, the system determines if the request is from a processor which is in a polite mode. If this is true, the system denies the request to access the cache line and continues executing the existing transaction.

Abstract: A computer system implementing transient blocking synchronization allows a memory location leased by a first process to be read-accessible to another process. In other words, more than one thread may have read-only type leases on a given memory location at a given time. Such “shared” leases expire when respective lease periods of the shared leases elapse.

Abstract: A computer system uses transient blocking synchronization for performing operations on shared memory. When performing operations on more than one memory location, the computer system obtains transient exclusive access to a first memory location. The computer system then obtains transient exclusive access to a second memory location, where the transient exclusive access to the second memory location does not expire prior to an expiration of the transient exclusive access to the first memory location or until explicitly unleased.

Abstract: A system and methods that provide compatibility across multiple versions of a software system, such as an execution engine or run-time system, are disclosed. The software system is structured so that it includes a master module, and one or more helper modules, each helper module being capable of processing applets (i.e., programs or content) that require a particular version of the software system. Each time an applet is to be processed by the software system, the master module determines which helper module should be used to process the applet, and starts the selected helper module if necessary. Compatibility with additional versions can be provided by providing additional helper modules. Because numerous helper modules may be executed simultaneously, applets that require different versions of the software system may be processed simultaneously.